xref: /petsc/src/ts/interface/ts.c (revision fe998a80077c9ee0917a39496df43fc256e1b478)
1 
2 #include <petsc-private/tsimpl.h>        /*I "petscts.h"  I*/
3 #include <petscdmshell.h>
4 #include <petscdmda.h>
5 #include <petscviewer.h>
6 #include <petscdraw.h>
7 
8 /* Logging support */
9 PetscClassId  TS_CLASSID, DMTS_CLASSID;
10 PetscLogEvent TS_Step, TS_PseudoComputeTimeStep, TS_FunctionEval, TS_JacobianEval;
11 
12 const char *const TSExactFinalTimeOptions[] = {"STEPOVER","INTERPOLATE","MATCHSTEP","TSExactFinalTimeOption","TS_EXACTFINALTIME_",0};
13 
14 #undef __FUNCT__
15 #define __FUNCT__ "TSSetTypeFromOptions"
16 /*
17   TSSetTypeFromOptions - Sets the type of ts from user options.
18 
19   Collective on TS
20 
21   Input Parameter:
22 . ts - The ts
23 
24   Level: intermediate
25 
26 .keywords: TS, set, options, database, type
27 .seealso: TSSetFromOptions(), TSSetType()
28 */
29 static PetscErrorCode TSSetTypeFromOptions(TS ts)
30 {
31   PetscBool      opt;
32   const char     *defaultType;
33   char           typeName[256];
34   PetscErrorCode ierr;
35 
36   PetscFunctionBegin;
37   if (((PetscObject)ts)->type_name) defaultType = ((PetscObject)ts)->type_name;
38   else defaultType = TSEULER;
39 
40   if (!TSRegisterAllCalled) {ierr = TSRegisterAll();CHKERRQ(ierr);}
41   ierr = PetscOptionsFList("-ts_type", "TS method"," TSSetType", TSList, defaultType, typeName, 256, &opt);CHKERRQ(ierr);
42   if (opt) {
43     ierr = TSSetType(ts, typeName);CHKERRQ(ierr);
44   } else {
45     ierr = TSSetType(ts, defaultType);CHKERRQ(ierr);
46   }
47   PetscFunctionReturn(0);
48 }
49 
50 struct _n_TSMonitorDrawCtx {
51   PetscViewer   viewer;
52   PetscDrawAxis axis;
53   Vec           initialsolution;
54   PetscBool     showinitial;
55   PetscInt      howoften;  /* when > 0 uses step % howoften, when negative only final solution plotted */
56   PetscBool     showtimestepandtime;
57   int           color;
58 };
59 
60 #undef __FUNCT__
61 #define __FUNCT__ "TSSetFromOptions"
62 /*@
63    TSSetFromOptions - Sets various TS parameters from user options.
64 
65    Collective on TS
66 
67    Input Parameter:
68 .  ts - the TS context obtained from TSCreate()
69 
70    Options Database Keys:
71 +  -ts_type <type> - TSEULER, TSBEULER, TSSUNDIALS, TSPSEUDO, TSCN, TSRK, TSTHETA, TSGL, TSSSP
72 .  -ts_max_steps maxsteps - maximum number of time-steps to take
73 .  -ts_final_time time - maximum time to compute to
74 .  -ts_dt dt - initial time step
75 .  -ts_exact_final_time <stepover,interpolate,matchstep> whether to stop at the exact given final time and how to compute the solution at that ti,e
76 .  -ts_max_snes_failures <maxfailures> - Maximum number of nonlinear solve failures allowed
77 .  -ts_max_reject <maxrejects> - Maximum number of step rejections before step fails
78 .  -ts_error_if_step_fails <true,false> - Error if no step succeeds
79 .  -ts_rtol <rtol> - relative tolerance for local truncation error
80 .  -ts_atol <atol> Absolute tolerance for local truncation error
81 .  -ts_monitor - print information at each timestep
82 .  -ts_monitor_lg_timestep - Monitor timestep size graphically
83 .  -ts_monitor_lg_solution - Monitor solution graphically
84 .  -ts_monitor_lg_error - Monitor error graphically
85 .  -ts_monitor_lg_snes_iterations - Monitor number nonlinear iterations for each timestep graphically
86 .  -ts_monitor_lg_ksp_iterations - Monitor number nonlinear iterations for each timestep graphically
87 .  -ts_monitor_sp_eig - Monitor eigenvalues of linearized operator graphically
88 .  -ts_monitor_draw_solution - Monitor solution graphically
89 .  -ts_monitor_draw_solution_phase - Monitor solution graphically with phase diagram
90 .  -ts_monitor_draw_error - Monitor error graphically
91 .  -ts_monitor_solution_binary <filename> - Save each solution to a binary file
92 -  -ts_monitor_solution_vtk <filename.vts> - Save each time step to a binary file, use filename-%%03D.vts
93 
94    Developer Note: We should unify all the -ts_monitor options in the way that -xxx_view has been unified
95 
96    Level: beginner
97 
98 .keywords: TS, timestep, set, options, database
99 
100 .seealso: TSGetType()
101 @*/
102 PetscErrorCode  TSSetFromOptions(TS ts)
103 {
104   PetscBool              opt,flg;
105   PetscErrorCode         ierr;
106   PetscViewer            monviewer;
107   char                   monfilename[PETSC_MAX_PATH_LEN];
108   SNES                   snes;
109   TSAdapt                adapt;
110   PetscReal              time_step;
111   TSExactFinalTimeOption eftopt;
112   char                   dir[16];
113 
114   PetscFunctionBegin;
115   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
116   ierr = PetscObjectOptionsBegin((PetscObject)ts);CHKERRQ(ierr);
117   /* Handle TS type options */
118   ierr = TSSetTypeFromOptions(ts);CHKERRQ(ierr);
119 
120   /* Handle generic TS options */
121   ierr = PetscOptionsInt("-ts_max_steps","Maximum number of time steps","TSSetDuration",ts->max_steps,&ts->max_steps,NULL);CHKERRQ(ierr);
122   ierr = PetscOptionsReal("-ts_final_time","Time to run to","TSSetDuration",ts->max_time,&ts->max_time,NULL);CHKERRQ(ierr);
123   ierr = PetscOptionsReal("-ts_init_time","Initial time","TSSetTime",ts->ptime,&ts->ptime,NULL);CHKERRQ(ierr);
124   ierr = PetscOptionsReal("-ts_dt","Initial time step","TSSetTimeStep",ts->time_step,&time_step,&flg);CHKERRQ(ierr);
125   if (flg) {
126     ierr = TSSetTimeStep(ts,time_step);CHKERRQ(ierr);
127   }
128   ierr = PetscOptionsEnum("-ts_exact_final_time","Option for handling of final time step","TSSetExactFinalTime",TSExactFinalTimeOptions,(PetscEnum)ts->exact_final_time,(PetscEnum*)&eftopt,&flg);CHKERRQ(ierr);
129   if (flg) {ierr = TSSetExactFinalTime(ts,eftopt);CHKERRQ(ierr);}
130   ierr = PetscOptionsInt("-ts_max_snes_failures","Maximum number of nonlinear solve failures","TSSetMaxSNESFailures",ts->max_snes_failures,&ts->max_snes_failures,NULL);CHKERRQ(ierr);
131   ierr = PetscOptionsInt("-ts_max_reject","Maximum number of step rejections before step fails","TSSetMaxStepRejections",ts->max_reject,&ts->max_reject,NULL);CHKERRQ(ierr);
132   ierr = PetscOptionsBool("-ts_error_if_step_fails","Error if no step succeeds","TSSetErrorIfStepFails",ts->errorifstepfailed,&ts->errorifstepfailed,NULL);CHKERRQ(ierr);
133   ierr = PetscOptionsReal("-ts_rtol","Relative tolerance for local truncation error","TSSetTolerances",ts->rtol,&ts->rtol,NULL);CHKERRQ(ierr);
134   ierr = PetscOptionsReal("-ts_atol","Absolute tolerance for local truncation error","TSSetTolerances",ts->atol,&ts->atol,NULL);CHKERRQ(ierr);
135 
136 #if defined(PETSC_HAVE_SAWS)
137   {
138   PetscBool set;
139   flg  = PETSC_FALSE;
140   ierr = PetscOptionsBool("-ts_saws_block","Block for SAWs memory snooper at end of TSSolve","PetscObjectSAWsBlock",((PetscObject)ts)->amspublishblock,&flg,&set);CHKERRQ(ierr);
141   if (set) {
142     ierr = PetscObjectSAWsSetBlock((PetscObject)ts,flg);CHKERRQ(ierr);
143   }
144   }
145 #endif
146 
147   /* Monitor options */
148   ierr = PetscOptionsString("-ts_monitor","Monitor timestep size","TSMonitorDefault","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
149   if (flg) {
150     ierr = PetscViewerASCIIOpen(PetscObjectComm((PetscObject)ts),monfilename,&monviewer);CHKERRQ(ierr);
151     ierr = TSMonitorSet(ts,TSMonitorDefault,monviewer,(PetscErrorCode (*)(void**))PetscViewerDestroy);CHKERRQ(ierr);
152   }
153   ierr = PetscOptionsString("-ts_monitor_python","Use Python function","TSMonitorSet",0,monfilename,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
154   if (flg) {ierr = PetscPythonMonitorSet((PetscObject)ts,monfilename);CHKERRQ(ierr);}
155 
156   ierr = PetscOptionsName("-ts_monitor_lg_timestep","Monitor timestep size graphically","TSMonitorLGTimeStep",&opt);CHKERRQ(ierr);
157   if (opt) {
158     TSMonitorLGCtx ctx;
159     PetscInt       howoften = 1;
160 
161     ierr = PetscOptionsInt("-ts_monitor_lg_timestep","Monitor timestep size graphically","TSMonitorLGTimeStep",howoften,&howoften,NULL);CHKERRQ(ierr);
162     ierr = TSMonitorLGCtxCreate(PetscObjectComm((PetscObject)ts),0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,howoften,&ctx);CHKERRQ(ierr);
163     ierr = TSMonitorSet(ts,TSMonitorLGTimeStep,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
164   }
165   ierr = PetscOptionsName("-ts_monitor_lg_solution","Monitor solution graphically","TSMonitorLGSolution",&opt);CHKERRQ(ierr);
166   if (opt) {
167     TSMonitorLGCtx ctx;
168     PetscInt       howoften = 1;
169 
170     ierr = PetscOptionsInt("-ts_monitor_lg_solution","Monitor solution graphically","TSMonitorLGSolution",howoften,&howoften,NULL);CHKERRQ(ierr);
171     ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);CHKERRQ(ierr);
172     ierr = TSMonitorSet(ts,TSMonitorLGSolution,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
173   }
174   ierr = PetscOptionsName("-ts_monitor_lg_error","Monitor error graphically","TSMonitorLGError",&opt);CHKERRQ(ierr);
175   if (opt) {
176     TSMonitorLGCtx ctx;
177     PetscInt       howoften = 1;
178 
179     ierr = PetscOptionsInt("-ts_monitor_lg_error","Monitor error graphically","TSMonitorLGError",howoften,&howoften,NULL);CHKERRQ(ierr);
180     ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);CHKERRQ(ierr);
181     ierr = TSMonitorSet(ts,TSMonitorLGError,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
182   }
183   ierr = PetscOptionsName("-ts_monitor_lg_snes_iterations","Monitor number nonlinear iterations for each timestep graphically","TSMonitorLGSNESIterations",&opt);CHKERRQ(ierr);
184   if (opt) {
185     TSMonitorLGCtx ctx;
186     PetscInt       howoften = 1;
187 
188     ierr = PetscOptionsInt("-ts_monitor_lg_snes_iterations","Monitor number nonlinear iterations for each timestep graphically","TSMonitorLGSNESIterations",howoften,&howoften,NULL);CHKERRQ(ierr);
189     ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,howoften,&ctx);CHKERRQ(ierr);
190     ierr = TSMonitorSet(ts,TSMonitorLGSNESIterations,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
191   }
192   ierr = PetscOptionsName("-ts_monitor_lg_ksp_iterations","Monitor number nonlinear iterations for each timestep graphically","TSMonitorLGKSPIterations",&opt);CHKERRQ(ierr);
193   if (opt) {
194     TSMonitorLGCtx ctx;
195     PetscInt       howoften = 1;
196 
197     ierr = PetscOptionsInt("-ts_monitor_lg_ksp_iterations","Monitor number nonlinear iterations for each timestep graphically","TSMonitorLGKSPIterations",howoften,&howoften,NULL);CHKERRQ(ierr);
198     ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,howoften,&ctx);CHKERRQ(ierr);
199     ierr = TSMonitorSet(ts,TSMonitorLGKSPIterations,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
200   }
201   ierr = PetscOptionsName("-ts_monitor_sp_eig","Monitor eigenvalues of linearized operator graphically","TSMonitorSPEig",&opt);CHKERRQ(ierr);
202   if (opt) {
203     TSMonitorSPEigCtx ctx;
204     PetscInt          howoften = 1;
205 
206     ierr = PetscOptionsInt("-ts_monitor_sp_eig","Monitor eigenvalues of linearized operator graphically","TSMonitorSPEig",howoften,&howoften,NULL);CHKERRQ(ierr);
207     ierr = TSMonitorSPEigCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);CHKERRQ(ierr);
208     ierr = TSMonitorSet(ts,TSMonitorSPEig,ctx,(PetscErrorCode (*)(void**))TSMonitorSPEigCtxDestroy);CHKERRQ(ierr);
209   }
210   opt  = PETSC_FALSE;
211   ierr = PetscOptionsName("-ts_monitor_draw_solution","Monitor solution graphically","TSMonitorDrawSolution",&opt);CHKERRQ(ierr);
212   if (opt) {
213     TSMonitorDrawCtx ctx;
214     PetscInt         howoften = 1;
215 
216     ierr = PetscOptionsInt("-ts_monitor_draw_solution","Monitor solution graphically","TSMonitorDrawSolution",howoften,&howoften,NULL);CHKERRQ(ierr);
217     ierr = TSMonitorDrawCtxCreate(PetscObjectComm((PetscObject)ts),0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);CHKERRQ(ierr);
218     ierr = TSMonitorSet(ts,TSMonitorDrawSolution,ctx,(PetscErrorCode (*)(void**))TSMonitorDrawCtxDestroy);CHKERRQ(ierr);
219   }
220   opt  = PETSC_FALSE;
221   ierr = PetscOptionsName("-ts_monitor_draw_solution_phase","Monitor solution graphically","TSMonitorDrawSolutionPhase",&opt);CHKERRQ(ierr);
222   if (opt) {
223     TSMonitorDrawCtx ctx;
224     PetscReal        bounds[4];
225     PetscInt         n = 4;
226     PetscDraw        draw;
227 
228     ierr = PetscOptionsRealArray("-ts_monitor_draw_solution_phase","Monitor solution graphically","TSMonitorDrawSolutionPhase",bounds,&n,NULL);CHKERRQ(ierr);
229     if (n != 4) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_ARG_WRONG,"Must provide bounding box of phase field");
230     ierr = TSMonitorDrawCtxCreate(PetscObjectComm((PetscObject)ts),0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,1,&ctx);CHKERRQ(ierr);
231     ierr = PetscViewerDrawGetDraw(ctx->viewer,0,&draw);CHKERRQ(ierr);
232     ierr = PetscDrawClear(draw);CHKERRQ(ierr);
233     ierr = PetscDrawAxisCreate(draw,&ctx->axis);CHKERRQ(ierr);
234     ierr = PetscDrawAxisSetLimits(ctx->axis,bounds[0],bounds[2],bounds[1],bounds[3]);CHKERRQ(ierr);
235     ierr = PetscDrawAxisSetLabels(ctx->axis,"Phase Diagram","Variable 1","Variable 2");CHKERRQ(ierr);
236     ierr = PetscDrawAxisDraw(ctx->axis);CHKERRQ(ierr);
237     /* ierr = PetscDrawSetCoordinates(draw,bounds[0],bounds[1],bounds[2],bounds[3]);CHKERRQ(ierr); */
238     ierr = TSMonitorSet(ts,TSMonitorDrawSolutionPhase,ctx,(PetscErrorCode (*)(void**))TSMonitorDrawCtxDestroy);CHKERRQ(ierr);
239   }
240   opt  = PETSC_FALSE;
241   ierr = PetscOptionsName("-ts_monitor_draw_error","Monitor error graphically","TSMonitorDrawError",&opt);CHKERRQ(ierr);
242   if (opt) {
243     TSMonitorDrawCtx ctx;
244     PetscInt         howoften = 1;
245 
246     ierr = PetscOptionsInt("-ts_monitor_draw_error","Monitor error graphically","TSMonitorDrawError",howoften,&howoften,NULL);CHKERRQ(ierr);
247     ierr = TSMonitorDrawCtxCreate(PetscObjectComm((PetscObject)ts),0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);CHKERRQ(ierr);
248     ierr = TSMonitorSet(ts,TSMonitorDrawError,ctx,(PetscErrorCode (*)(void**))TSMonitorDrawCtxDestroy);CHKERRQ(ierr);
249   }
250   opt  = PETSC_FALSE;
251   ierr = PetscOptionsString("-ts_monitor_solution_binary","Save each solution to a binary file","TSMonitorSolutionBinary",0,monfilename,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
252   if (flg) {
253     PetscViewer ctx;
254     if (monfilename[0]) {
255       ierr = PetscViewerBinaryOpen(PetscObjectComm((PetscObject)ts),monfilename,FILE_MODE_WRITE,&ctx);CHKERRQ(ierr);
256       ierr = TSMonitorSet(ts,TSMonitorSolutionBinary,ctx,(PetscErrorCode (*)(void**))PetscViewerDestroy);CHKERRQ(ierr);
257     } else {
258       ctx = PETSC_VIEWER_BINARY_(PetscObjectComm((PetscObject)ts));
259       ierr = TSMonitorSet(ts,TSMonitorSolutionBinary,ctx,(PetscErrorCode (*)(void**))NULL);CHKERRQ(ierr);
260     }
261   }
262   opt  = PETSC_FALSE;
263   ierr = PetscOptionsString("-ts_monitor_solution_vtk","Save each time step to a binary file, use filename-%%03D.vts","TSMonitorSolutionVTK",0,monfilename,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
264   if (flg) {
265     const char *ptr,*ptr2;
266     char       *filetemplate;
267     if (!monfilename[0]) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"-ts_monitor_solution_vtk requires a file template, e.g. filename-%%03D.vts");
268     /* Do some cursory validation of the input. */
269     ierr = PetscStrstr(monfilename,"%",(char**)&ptr);CHKERRQ(ierr);
270     if (!ptr) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"-ts_monitor_solution_vtk requires a file template, e.g. filename-%%03D.vts");
271     for (ptr++; ptr && *ptr; ptr++) {
272       ierr = PetscStrchr("DdiouxX",*ptr,(char**)&ptr2);CHKERRQ(ierr);
273       if (!ptr2 && (*ptr < '0' || '9' < *ptr)) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"Invalid file template argument to -ts_monitor_solution_vtk, should look like filename-%%03D.vts");
274       if (ptr2) break;
275     }
276     ierr = PetscStrallocpy(monfilename,&filetemplate);CHKERRQ(ierr);
277     ierr = TSMonitorSet(ts,TSMonitorSolutionVTK,filetemplate,(PetscErrorCode (*)(void**))TSMonitorSolutionVTKDestroy);CHKERRQ(ierr);
278   }
279 
280   ierr = PetscOptionsString("-ts_monitor_dmda_ray","Display a ray of the solution","None","y=0",dir,16,&flg);CHKERRQ(ierr);
281   if (flg) {
282     TSMonitorDMDARayCtx *rayctx;
283     int                  ray = 0;
284     DMDADirection        ddir;
285     DM                   da;
286     PetscMPIInt          rank;
287 
288     if (dir[1] != '=') SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_ARG_WRONG,"Unknown ray %s",dir);
289     if (dir[0] == 'x') ddir = DMDA_X;
290     else if (dir[0] == 'y') ddir = DMDA_Y;
291     else SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_ARG_WRONG,"Unknown ray %s",dir);
292     sscanf(dir+2,"%d",&ray);
293 
294     ierr = PetscInfo2(((PetscObject)ts),"Displaying DMDA ray %c = %D\n",dir[0],ray);CHKERRQ(ierr);
295     ierr = PetscNew(&rayctx);CHKERRQ(ierr);
296     ierr = TSGetDM(ts,&da);CHKERRQ(ierr);
297     ierr = DMDAGetRay(da,ddir,ray,&rayctx->ray,&rayctx->scatter);CHKERRQ(ierr);
298     ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)ts),&rank);CHKERRQ(ierr);
299     if (!rank) {
300       ierr = PetscViewerDrawOpen(PETSC_COMM_SELF,0,0,0,0,600,300,&rayctx->viewer);CHKERRQ(ierr);
301     }
302     rayctx->lgctx = NULL;
303     ierr = TSMonitorSet(ts,TSMonitorDMDARay,rayctx,TSMonitorDMDARayDestroy);CHKERRQ(ierr);
304   }
305   ierr = PetscOptionsString("-ts_monitor_lg_dmda_ray","Display a ray of the solution","None","x=0",dir,16,&flg);CHKERRQ(ierr);
306   if (flg) {
307     TSMonitorDMDARayCtx *rayctx;
308     int                 ray = 0;
309     DMDADirection       ddir;
310     DM                  da;
311     PetscInt            howoften = 1;
312 
313     if (dir[1] != '=') SETERRQ1(PetscObjectComm((PetscObject) ts), PETSC_ERR_ARG_WRONG, "Malformed ray %s", dir);
314     if      (dir[0] == 'x') ddir = DMDA_X;
315     else if (dir[0] == 'y') ddir = DMDA_Y;
316     else SETERRQ1(PetscObjectComm((PetscObject) ts), PETSC_ERR_ARG_WRONG, "Unknown ray direction %s", dir);
317     sscanf(dir+2, "%d", &ray);
318 
319     ierr = PetscInfo2(((PetscObject) ts),"Displaying LG DMDA ray %c = %D\n", dir[0], ray);CHKERRQ(ierr);
320     ierr = PetscNew(&rayctx);CHKERRQ(ierr);
321     ierr = TSGetDM(ts, &da);CHKERRQ(ierr);
322     ierr = DMDAGetRay(da, ddir, ray, &rayctx->ray, &rayctx->scatter);CHKERRQ(ierr);
323     ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&rayctx->lgctx);CHKERRQ(ierr);
324     ierr = TSMonitorSet(ts, TSMonitorLGDMDARay, rayctx, TSMonitorDMDARayDestroy);CHKERRQ(ierr);
325   }
326 
327   /*
328      This code is all wrong. One is creating objects inside the TSSetFromOptions() so if run with the options gui
329      will bleed memory. Also one is using a PetscOptionsBegin() inside a PetscOptionsBegin()
330   */
331   ierr = TSGetAdapt(ts,&adapt);CHKERRQ(ierr);
332   ierr = TSAdaptSetFromOptions(adapt);CHKERRQ(ierr);
333 
334   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
335   if (ts->problem_type == TS_LINEAR) {ierr = SNESSetType(snes,SNESKSPONLY);CHKERRQ(ierr);}
336 
337   /* Handle specific TS options */
338   if (ts->ops->setfromoptions) {
339     ierr = (*ts->ops->setfromoptions)(ts);CHKERRQ(ierr);
340   }
341 
342   /* process any options handlers added with PetscObjectAddOptionsHandler() */
343   ierr = PetscObjectProcessOptionsHandlers((PetscObject)ts);CHKERRQ(ierr);
344   ierr = PetscOptionsEnd();CHKERRQ(ierr);
345   PetscFunctionReturn(0);
346 }
347 
348 #undef __FUNCT__
349 #undef __FUNCT__
350 #define __FUNCT__ "TSComputeRHSJacobian"
351 /*@
352    TSComputeRHSJacobian - Computes the Jacobian matrix that has been
353       set with TSSetRHSJacobian().
354 
355    Collective on TS and Vec
356 
357    Input Parameters:
358 +  ts - the TS context
359 .  t - current timestep
360 -  U - input vector
361 
362    Output Parameters:
363 +  A - Jacobian matrix
364 .  B - optional preconditioning matrix
365 -  flag - flag indicating matrix structure
366 
367    Notes:
368    Most users should not need to explicitly call this routine, as it
369    is used internally within the nonlinear solvers.
370 
371    See KSPSetOperators() for important information about setting the
372    flag parameter.
373 
374    Level: developer
375 
376 .keywords: SNES, compute, Jacobian, matrix
377 
378 .seealso:  TSSetRHSJacobian(), KSPSetOperators()
379 @*/
380 PetscErrorCode  TSComputeRHSJacobian(TS ts,PetscReal t,Vec U,Mat A,Mat B)
381 {
382   PetscErrorCode ierr;
383   PetscObjectState Ustate;
384   DM             dm;
385   DMTS           tsdm;
386   TSRHSJacobian  rhsjacobianfunc;
387   void           *ctx;
388   TSIJacobian    ijacobianfunc;
389 
390   PetscFunctionBegin;
391   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
392   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
393   PetscCheckSameComm(ts,1,U,3);
394   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
395   ierr = DMGetDMTS(dm,&tsdm);CHKERRQ(ierr);
396   ierr = DMTSGetRHSJacobian(dm,&rhsjacobianfunc,&ctx);CHKERRQ(ierr);
397   ierr = DMTSGetIJacobian(dm,&ijacobianfunc,NULL);CHKERRQ(ierr);
398   ierr = PetscObjectStateGet((PetscObject)U,&Ustate);CHKERRQ(ierr);
399   if (ts->rhsjacobian.time == t && (ts->problem_type == TS_LINEAR || (ts->rhsjacobian.X == U && ts->rhsjacobian.Xstate == Ustate))) {
400     PetscFunctionReturn(0);
401   }
402 
403   if (!rhsjacobianfunc && !ijacobianfunc) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"Must call TSSetRHSJacobian() and / or TSSetIJacobian()");
404 
405   if (ts->rhsjacobian.reuse) {
406     ierr = MatShift(A,-ts->rhsjacobian.shift);CHKERRQ(ierr);
407     ierr = MatScale(A,1./ts->rhsjacobian.scale);CHKERRQ(ierr);
408     if (A != B) {
409       ierr = MatShift(B,-ts->rhsjacobian.shift);CHKERRQ(ierr);
410       ierr = MatScale(B,1./ts->rhsjacobian.scale);CHKERRQ(ierr);
411     }
412     ts->rhsjacobian.shift = 0;
413     ts->rhsjacobian.scale = 1.;
414   }
415 
416   if (rhsjacobianfunc) {
417     ierr = PetscLogEventBegin(TS_JacobianEval,ts,U,A,B);CHKERRQ(ierr);
418     PetscStackPush("TS user Jacobian function");
419     ierr = (*rhsjacobianfunc)(ts,t,U,A,B,ctx);CHKERRQ(ierr);
420     PetscStackPop;
421     ierr = PetscLogEventEnd(TS_JacobianEval,ts,U,A,B);CHKERRQ(ierr);
422     /* make sure user returned a correct Jacobian and preconditioner */
423     PetscValidHeaderSpecific(A,MAT_CLASSID,4);
424     PetscValidHeaderSpecific(B,MAT_CLASSID,5);
425   } else {
426     ierr = MatZeroEntries(A);CHKERRQ(ierr);
427     if (A != B) {ierr = MatZeroEntries(B);CHKERRQ(ierr);}
428   }
429   ts->rhsjacobian.time       = t;
430   ts->rhsjacobian.X          = U;
431   ierr                       = PetscObjectStateGet((PetscObject)U,&ts->rhsjacobian.Xstate);CHKERRQ(ierr);
432   PetscFunctionReturn(0);
433 }
434 
435 #undef __FUNCT__
436 #define __FUNCT__ "TSComputeRHSFunction"
437 /*@
438    TSComputeRHSFunction - Evaluates the right-hand-side function.
439 
440    Collective on TS and Vec
441 
442    Input Parameters:
443 +  ts - the TS context
444 .  t - current time
445 -  U - state vector
446 
447    Output Parameter:
448 .  y - right hand side
449 
450    Note:
451    Most users should not need to explicitly call this routine, as it
452    is used internally within the nonlinear solvers.
453 
454    Level: developer
455 
456 .keywords: TS, compute
457 
458 .seealso: TSSetRHSFunction(), TSComputeIFunction()
459 @*/
460 PetscErrorCode TSComputeRHSFunction(TS ts,PetscReal t,Vec U,Vec y)
461 {
462   PetscErrorCode ierr;
463   TSRHSFunction  rhsfunction;
464   TSIFunction    ifunction;
465   void           *ctx;
466   DM             dm;
467 
468   PetscFunctionBegin;
469   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
470   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
471   PetscValidHeaderSpecific(y,VEC_CLASSID,4);
472   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
473   ierr = DMTSGetRHSFunction(dm,&rhsfunction,&ctx);CHKERRQ(ierr);
474   ierr = DMTSGetIFunction(dm,&ifunction,NULL);CHKERRQ(ierr);
475 
476   if (!rhsfunction && !ifunction) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"Must call TSSetRHSFunction() and / or TSSetIFunction()");
477 
478   ierr = PetscLogEventBegin(TS_FunctionEval,ts,U,y,0);CHKERRQ(ierr);
479   if (rhsfunction) {
480     PetscStackPush("TS user right-hand-side function");
481     ierr = (*rhsfunction)(ts,t,U,y,ctx);CHKERRQ(ierr);
482     PetscStackPop;
483   } else {
484     ierr = VecZeroEntries(y);CHKERRQ(ierr);
485   }
486 
487   ierr = PetscLogEventEnd(TS_FunctionEval,ts,U,y,0);CHKERRQ(ierr);
488   PetscFunctionReturn(0);
489 }
490 
491 #undef __FUNCT__
492 #define __FUNCT__ "TSComputeSolutionFunction"
493 /*@
494    TSComputeSolutionFunction - Evaluates the solution function.
495 
496    Collective on TS and Vec
497 
498    Input Parameters:
499 +  ts - the TS context
500 -  t - current time
501 
502    Output Parameter:
503 .  U - the solution
504 
505    Note:
506    Most users should not need to explicitly call this routine, as it
507    is used internally within the nonlinear solvers.
508 
509    Level: developer
510 
511 .keywords: TS, compute
512 
513 .seealso: TSSetSolutionFunction(), TSSetRHSFunction(), TSComputeIFunction()
514 @*/
515 PetscErrorCode TSComputeSolutionFunction(TS ts,PetscReal t,Vec U)
516 {
517   PetscErrorCode     ierr;
518   TSSolutionFunction solutionfunction;
519   void               *ctx;
520   DM                 dm;
521 
522   PetscFunctionBegin;
523   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
524   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
525   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
526   ierr = DMTSGetSolutionFunction(dm,&solutionfunction,&ctx);CHKERRQ(ierr);
527 
528   if (solutionfunction) {
529     PetscStackPush("TS user solution function");
530     ierr = (*solutionfunction)(ts,t,U,ctx);CHKERRQ(ierr);
531     PetscStackPop;
532   }
533   PetscFunctionReturn(0);
534 }
535 #undef __FUNCT__
536 #define __FUNCT__ "TSComputeForcingFunction"
537 /*@
538    TSComputeForcingFunction - Evaluates the forcing function.
539 
540    Collective on TS and Vec
541 
542    Input Parameters:
543 +  ts - the TS context
544 -  t - current time
545 
546    Output Parameter:
547 .  U - the function value
548 
549    Note:
550    Most users should not need to explicitly call this routine, as it
551    is used internally within the nonlinear solvers.
552 
553    Level: developer
554 
555 .keywords: TS, compute
556 
557 .seealso: TSSetSolutionFunction(), TSSetRHSFunction(), TSComputeIFunction()
558 @*/
559 PetscErrorCode TSComputeForcingFunction(TS ts,PetscReal t,Vec U)
560 {
561   PetscErrorCode     ierr, (*forcing)(TS,PetscReal,Vec,void*);
562   void               *ctx;
563   DM                 dm;
564 
565   PetscFunctionBegin;
566   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
567   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
568   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
569   ierr = DMTSGetForcingFunction(dm,&forcing,&ctx);CHKERRQ(ierr);
570 
571   if (forcing) {
572     PetscStackPush("TS user forcing function");
573     ierr = (*forcing)(ts,t,U,ctx);CHKERRQ(ierr);
574     PetscStackPop;
575   }
576   PetscFunctionReturn(0);
577 }
578 
579 #undef __FUNCT__
580 #define __FUNCT__ "TSGetRHSVec_Private"
581 static PetscErrorCode TSGetRHSVec_Private(TS ts,Vec *Frhs)
582 {
583   Vec            F;
584   PetscErrorCode ierr;
585 
586   PetscFunctionBegin;
587   *Frhs = NULL;
588   ierr  = TSGetIFunction(ts,&F,NULL,NULL);CHKERRQ(ierr);
589   if (!ts->Frhs) {
590     ierr = VecDuplicate(F,&ts->Frhs);CHKERRQ(ierr);
591   }
592   *Frhs = ts->Frhs;
593   PetscFunctionReturn(0);
594 }
595 
596 #undef __FUNCT__
597 #define __FUNCT__ "TSGetRHSMats_Private"
598 static PetscErrorCode TSGetRHSMats_Private(TS ts,Mat *Arhs,Mat *Brhs)
599 {
600   Mat            A,B;
601   PetscErrorCode ierr;
602 
603   PetscFunctionBegin;
604   if (Arhs) *Arhs = NULL;
605   if (Brhs) *Brhs = NULL;
606   ierr = TSGetIJacobian(ts,&A,&B,NULL,NULL);CHKERRQ(ierr);
607   if (Arhs) {
608     if (!ts->Arhs) {
609       ierr = MatDuplicate(A,MAT_DO_NOT_COPY_VALUES,&ts->Arhs);CHKERRQ(ierr);
610     }
611     *Arhs = ts->Arhs;
612   }
613   if (Brhs) {
614     if (!ts->Brhs) {
615       if (A != B) {
616         ierr = MatDuplicate(B,MAT_DO_NOT_COPY_VALUES,&ts->Brhs);CHKERRQ(ierr);
617       } else {
618         ts->Brhs = ts->Arhs;
619         ierr = PetscObjectReference((PetscObject)ts->Arhs);CHKERRQ(ierr);
620       }
621     }
622     *Brhs = ts->Brhs;
623   }
624   PetscFunctionReturn(0);
625 }
626 
627 #undef __FUNCT__
628 #define __FUNCT__ "TSComputeIFunction"
629 /*@
630    TSComputeIFunction - Evaluates the DAE residual written in implicit form F(t,U,Udot)=0
631 
632    Collective on TS and Vec
633 
634    Input Parameters:
635 +  ts - the TS context
636 .  t - current time
637 .  U - state vector
638 .  Udot - time derivative of state vector
639 -  imex - flag indicates if the method is IMEX so that the RHSFunction should be kept separate
640 
641    Output Parameter:
642 .  Y - right hand side
643 
644    Note:
645    Most users should not need to explicitly call this routine, as it
646    is used internally within the nonlinear solvers.
647 
648    If the user did did not write their equations in implicit form, this
649    function recasts them in implicit form.
650 
651    Level: developer
652 
653 .keywords: TS, compute
654 
655 .seealso: TSSetIFunction(), TSComputeRHSFunction()
656 @*/
657 PetscErrorCode TSComputeIFunction(TS ts,PetscReal t,Vec U,Vec Udot,Vec Y,PetscBool imex)
658 {
659   PetscErrorCode ierr;
660   TSIFunction    ifunction;
661   TSRHSFunction  rhsfunction;
662   void           *ctx;
663   DM             dm;
664 
665   PetscFunctionBegin;
666   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
667   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
668   PetscValidHeaderSpecific(Udot,VEC_CLASSID,4);
669   PetscValidHeaderSpecific(Y,VEC_CLASSID,5);
670 
671   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
672   ierr = DMTSGetIFunction(dm,&ifunction,&ctx);CHKERRQ(ierr);
673   ierr = DMTSGetRHSFunction(dm,&rhsfunction,NULL);CHKERRQ(ierr);
674 
675   if (!rhsfunction && !ifunction) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"Must call TSSetRHSFunction() and / or TSSetIFunction()");
676 
677   ierr = PetscLogEventBegin(TS_FunctionEval,ts,U,Udot,Y);CHKERRQ(ierr);
678   if (ifunction) {
679     PetscStackPush("TS user implicit function");
680     ierr = (*ifunction)(ts,t,U,Udot,Y,ctx);CHKERRQ(ierr);
681     PetscStackPop;
682   }
683   if (imex) {
684     if (!ifunction) {
685       ierr = VecCopy(Udot,Y);CHKERRQ(ierr);
686     }
687   } else if (rhsfunction) {
688     if (ifunction) {
689       Vec Frhs;
690       ierr = TSGetRHSVec_Private(ts,&Frhs);CHKERRQ(ierr);
691       ierr = TSComputeRHSFunction(ts,t,U,Frhs);CHKERRQ(ierr);
692       ierr = VecAXPY(Y,-1,Frhs);CHKERRQ(ierr);
693     } else {
694       ierr = TSComputeRHSFunction(ts,t,U,Y);CHKERRQ(ierr);
695       ierr = VecAYPX(Y,-1,Udot);CHKERRQ(ierr);
696     }
697   }
698   ierr = PetscLogEventEnd(TS_FunctionEval,ts,U,Udot,Y);CHKERRQ(ierr);
699   PetscFunctionReturn(0);
700 }
701 
702 #undef __FUNCT__
703 #define __FUNCT__ "TSComputeIJacobian"
704 /*@
705    TSComputeIJacobian - Evaluates the Jacobian of the DAE
706 
707    Collective on TS and Vec
708 
709    Input
710       Input Parameters:
711 +  ts - the TS context
712 .  t - current timestep
713 .  U - state vector
714 .  Udot - time derivative of state vector
715 .  shift - shift to apply, see note below
716 -  imex - flag indicates if the method is IMEX so that the RHSJacobian should be kept separate
717 
718    Output Parameters:
719 +  A - Jacobian matrix
720 .  B - optional preconditioning matrix
721 -  flag - flag indicating matrix structure
722 
723    Notes:
724    If F(t,U,Udot)=0 is the DAE, the required Jacobian is
725 
726    dF/dU + shift*dF/dUdot
727 
728    Most users should not need to explicitly call this routine, as it
729    is used internally within the nonlinear solvers.
730 
731    Level: developer
732 
733 .keywords: TS, compute, Jacobian, matrix
734 
735 .seealso:  TSSetIJacobian()
736 @*/
737 PetscErrorCode TSComputeIJacobian(TS ts,PetscReal t,Vec U,Vec Udot,PetscReal shift,Mat A,Mat B,PetscBool imex)
738 {
739   PetscErrorCode ierr;
740   TSIJacobian    ijacobian;
741   TSRHSJacobian  rhsjacobian;
742   DM             dm;
743   void           *ctx;
744 
745   PetscFunctionBegin;
746   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
747   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
748   PetscValidHeaderSpecific(Udot,VEC_CLASSID,4);
749   PetscValidPointer(A,6);
750   PetscValidHeaderSpecific(A,MAT_CLASSID,6);
751   PetscValidPointer(B,7);
752   PetscValidHeaderSpecific(B,MAT_CLASSID,7);
753 
754   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
755   ierr = DMTSGetIJacobian(dm,&ijacobian,&ctx);CHKERRQ(ierr);
756   ierr = DMTSGetRHSJacobian(dm,&rhsjacobian,NULL);CHKERRQ(ierr);
757 
758   if (!rhsjacobian && !ijacobian) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"Must call TSSetRHSJacobian() and / or TSSetIJacobian()");
759 
760   ierr = PetscLogEventBegin(TS_JacobianEval,ts,U,A,B);CHKERRQ(ierr);
761   if (ijacobian) {
762     PetscStackPush("TS user implicit Jacobian");
763     ierr = (*ijacobian)(ts,t,U,Udot,shift,A,B,ctx);CHKERRQ(ierr);
764     PetscStackPop;
765     /* make sure user returned a correct Jacobian and preconditioner */
766     PetscValidHeaderSpecific(A,MAT_CLASSID,4);
767     PetscValidHeaderSpecific(B,MAT_CLASSID,5);
768   }
769   if (imex) {
770     if (!ijacobian) {  /* system was written as Udot = G(t,U) */
771       ierr = MatZeroEntries(A);CHKERRQ(ierr);
772       ierr = MatShift(A,shift);CHKERRQ(ierr);
773       if (A != B) {
774         ierr = MatZeroEntries(B);CHKERRQ(ierr);
775         ierr = MatShift(B,shift);CHKERRQ(ierr);
776       }
777     }
778   } else {
779     Mat Arhs = NULL,Brhs = NULL;
780     if (rhsjacobian) {
781       if (ijacobian) {
782         ierr = TSGetRHSMats_Private(ts,&Arhs,&Brhs);CHKERRQ(ierr);
783       } else {
784         ierr = TSGetIJacobian(ts,&Arhs,&Brhs,NULL,NULL);CHKERRQ(ierr);
785       }
786       ierr = TSComputeRHSJacobian(ts,t,U,Arhs,Brhs);CHKERRQ(ierr);
787     }
788     if (Arhs == A) {           /* No IJacobian, so we only have the RHS matrix */
789       ts->rhsjacobian.scale = -1;
790       ts->rhsjacobian.shift = shift;
791       ierr = MatScale(A,-1);CHKERRQ(ierr);
792       ierr = MatShift(A,shift);CHKERRQ(ierr);
793       if (A != B) {
794         ierr = MatScale(B,-1);CHKERRQ(ierr);
795         ierr = MatShift(B,shift);CHKERRQ(ierr);
796       }
797     } else if (Arhs) {          /* Both IJacobian and RHSJacobian */
798       MatStructure axpy = DIFFERENT_NONZERO_PATTERN;
799       if (!ijacobian) {         /* No IJacobian provided, but we have a separate RHS matrix */
800         ierr = MatZeroEntries(A);CHKERRQ(ierr);
801         ierr = MatShift(A,shift);CHKERRQ(ierr);
802         if (A != B) {
803           ierr = MatZeroEntries(B);CHKERRQ(ierr);
804           ierr = MatShift(B,shift);CHKERRQ(ierr);
805         }
806       }
807       ierr = MatAXPY(A,-1,Arhs,axpy);CHKERRQ(ierr);
808       if (A != B) {
809         ierr = MatAXPY(B,-1,Brhs,axpy);CHKERRQ(ierr);
810       }
811     }
812   }
813   ierr = PetscLogEventEnd(TS_JacobianEval,ts,U,A,B);CHKERRQ(ierr);
814   PetscFunctionReturn(0);
815 }
816 
817 #undef __FUNCT__
818 #define __FUNCT__ "TSSetRHSFunction"
819 /*@C
820     TSSetRHSFunction - Sets the routine for evaluating the function,
821     where U_t = G(t,u).
822 
823     Logically Collective on TS
824 
825     Input Parameters:
826 +   ts - the TS context obtained from TSCreate()
827 .   r - vector to put the computed right hand side (or NULL to have it created)
828 .   f - routine for evaluating the right-hand-side function
829 -   ctx - [optional] user-defined context for private data for the
830           function evaluation routine (may be NULL)
831 
832     Calling sequence of func:
833 $     func (TS ts,PetscReal t,Vec u,Vec F,void *ctx);
834 
835 +   t - current timestep
836 .   u - input vector
837 .   F - function vector
838 -   ctx - [optional] user-defined function context
839 
840     Level: beginner
841 
842 .keywords: TS, timestep, set, right-hand-side, function
843 
844 .seealso: TSSetRHSJacobian(), TSSetIJacobian(), TSSetIFunction()
845 @*/
846 PetscErrorCode  TSSetRHSFunction(TS ts,Vec r,PetscErrorCode (*f)(TS,PetscReal,Vec,Vec,void*),void *ctx)
847 {
848   PetscErrorCode ierr;
849   SNES           snes;
850   Vec            ralloc = NULL;
851   DM             dm;
852 
853   PetscFunctionBegin;
854   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
855   if (r) PetscValidHeaderSpecific(r,VEC_CLASSID,2);
856 
857   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
858   ierr = DMTSSetRHSFunction(dm,f,ctx);CHKERRQ(ierr);
859   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
860   if (!r && !ts->dm && ts->vec_sol) {
861     ierr = VecDuplicate(ts->vec_sol,&ralloc);CHKERRQ(ierr);
862     r    = ralloc;
863   }
864   ierr = SNESSetFunction(snes,r,SNESTSFormFunction,ts);CHKERRQ(ierr);
865   ierr = VecDestroy(&ralloc);CHKERRQ(ierr);
866   PetscFunctionReturn(0);
867 }
868 
869 #undef __FUNCT__
870 #define __FUNCT__ "TSSetSolutionFunction"
871 /*@C
872     TSSetSolutionFunction - Provide a function that computes the solution of the ODE or DAE
873 
874     Logically Collective on TS
875 
876     Input Parameters:
877 +   ts - the TS context obtained from TSCreate()
878 .   f - routine for evaluating the solution
879 -   ctx - [optional] user-defined context for private data for the
880           function evaluation routine (may be NULL)
881 
882     Calling sequence of func:
883 $     func (TS ts,PetscReal t,Vec u,void *ctx);
884 
885 +   t - current timestep
886 .   u - output vector
887 -   ctx - [optional] user-defined function context
888 
889     Notes:
890     This routine is used for testing accuracy of time integration schemes when you already know the solution.
891     If analytic solutions are not known for your system, consider using the Method of Manufactured Solutions to
892     create closed-form solutions with non-physical forcing terms.
893 
894     For low-dimensional problems solved in serial, such as small discrete systems, TSMonitorLGError() can be used to monitor the error history.
895 
896     Level: beginner
897 
898 .keywords: TS, timestep, set, right-hand-side, function
899 
900 .seealso: TSSetRHSJacobian(), TSSetIJacobian(), TSComputeSolutionFunction(), TSSetForcingFunction()
901 @*/
902 PetscErrorCode  TSSetSolutionFunction(TS ts,PetscErrorCode (*f)(TS,PetscReal,Vec,void*),void *ctx)
903 {
904   PetscErrorCode ierr;
905   DM             dm;
906 
907   PetscFunctionBegin;
908   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
909   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
910   ierr = DMTSSetSolutionFunction(dm,f,ctx);CHKERRQ(ierr);
911   PetscFunctionReturn(0);
912 }
913 
914 #undef __FUNCT__
915 #define __FUNCT__ "TSSetForcingFunction"
916 /*@C
917     TSSetForcingFunction - Provide a function that computes a forcing term for a ODE or PDE
918 
919     Logically Collective on TS
920 
921     Input Parameters:
922 +   ts - the TS context obtained from TSCreate()
923 .   f - routine for evaluating the forcing function
924 -   ctx - [optional] user-defined context for private data for the
925           function evaluation routine (may be NULL)
926 
927     Calling sequence of func:
928 $     func (TS ts,PetscReal t,Vec u,void *ctx);
929 
930 +   t - current timestep
931 .   u - output vector
932 -   ctx - [optional] user-defined function context
933 
934     Notes:
935     This routine is useful for testing accuracy of time integration schemes when using the Method of Manufactured Solutions to
936     create closed-form solutions with a non-physical forcing term.
937 
938     For low-dimensional problems solved in serial, such as small discrete systems, TSMonitorLGError() can be used to monitor the error history.
939 
940     Level: beginner
941 
942 .keywords: TS, timestep, set, right-hand-side, function
943 
944 .seealso: TSSetRHSJacobian(), TSSetIJacobian(), TSComputeSolutionFunction(), TSSetSolutionFunction()
945 @*/
946 PetscErrorCode  TSSetForcingFunction(TS ts,PetscErrorCode (*f)(TS,PetscReal,Vec,void*),void *ctx)
947 {
948   PetscErrorCode ierr;
949   DM             dm;
950 
951   PetscFunctionBegin;
952   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
953   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
954   ierr = DMTSSetForcingFunction(dm,f,ctx);CHKERRQ(ierr);
955   PetscFunctionReturn(0);
956 }
957 
958 #undef __FUNCT__
959 #define __FUNCT__ "TSSetRHSJacobian"
960 /*@C
961    TSSetRHSJacobian - Sets the function to compute the Jacobian of F,
962    where U_t = G(U,t), as well as the location to store the matrix.
963 
964    Logically Collective on TS
965 
966    Input Parameters:
967 +  ts  - the TS context obtained from TSCreate()
968 .  Amat - (approximate) Jacobian matrix
969 .  Pmat - matrix from which preconditioner is to be constructed (usually the same as Amat)
970 .  f   - the Jacobian evaluation routine
971 -  ctx - [optional] user-defined context for private data for the
972          Jacobian evaluation routine (may be NULL)
973 
974    Calling sequence of func:
975 $     func (TS ts,PetscReal t,Vec u,Mat A,Mat B,void *ctx);
976 
977 +  t - current timestep
978 .  u - input vector
979 .  Amat - (approximate) Jacobian matrix
980 .  Pmat - matrix from which preconditioner is to be constructed (usually the same as Amat)
981 -  ctx - [optional] user-defined context for matrix evaluation routine
982 
983 
984    Level: beginner
985 
986 .keywords: TS, timestep, set, right-hand-side, Jacobian
987 
988 .seealso: SNESComputeJacobianDefaultColor(), TSSetRHSFunction(), TSRHSJacobianSetReuse(), TSSetIJacobian()
989 
990 @*/
991 PetscErrorCode  TSSetRHSJacobian(TS ts,Mat Amat,Mat Pmat,TSRHSJacobian f,void *ctx)
992 {
993   PetscErrorCode ierr;
994   SNES           snes;
995   DM             dm;
996   TSIJacobian    ijacobian;
997 
998   PetscFunctionBegin;
999   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1000   if (Amat) PetscValidHeaderSpecific(Amat,MAT_CLASSID,2);
1001   if (Pmat) PetscValidHeaderSpecific(Pmat,MAT_CLASSID,3);
1002   if (Amat) PetscCheckSameComm(ts,1,Amat,2);
1003   if (Pmat) PetscCheckSameComm(ts,1,Pmat,3);
1004 
1005   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1006   ierr = DMTSSetRHSJacobian(dm,f,ctx);CHKERRQ(ierr);
1007   if (f == TSComputeRHSJacobianConstant) {
1008     /* Handle this case automatically for the user; otherwise user should call themselves. */
1009     ierr = TSRHSJacobianSetReuse(ts,PETSC_TRUE);CHKERRQ(ierr);
1010   }
1011   ierr = DMTSGetIJacobian(dm,&ijacobian,NULL);CHKERRQ(ierr);
1012   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1013   if (!ijacobian) {
1014     ierr = SNESSetJacobian(snes,Amat,Pmat,SNESTSFormJacobian,ts);CHKERRQ(ierr);
1015   }
1016   if (Amat) {
1017     ierr = PetscObjectReference((PetscObject)Amat);CHKERRQ(ierr);
1018     ierr = MatDestroy(&ts->Arhs);CHKERRQ(ierr);
1019 
1020     ts->Arhs = Amat;
1021   }
1022   if (Pmat) {
1023     ierr = PetscObjectReference((PetscObject)Pmat);CHKERRQ(ierr);
1024     ierr = MatDestroy(&ts->Brhs);CHKERRQ(ierr);
1025 
1026     ts->Brhs = Pmat;
1027   }
1028   PetscFunctionReturn(0);
1029 }
1030 
1031 
1032 #undef __FUNCT__
1033 #define __FUNCT__ "TSSetIFunction"
1034 /*@C
1035    TSSetIFunction - Set the function to compute F(t,U,U_t) where F() = 0 is the DAE to be solved.
1036 
1037    Logically Collective on TS
1038 
1039    Input Parameters:
1040 +  ts  - the TS context obtained from TSCreate()
1041 .  r   - vector to hold the residual (or NULL to have it created internally)
1042 .  f   - the function evaluation routine
1043 -  ctx - user-defined context for private data for the function evaluation routine (may be NULL)
1044 
1045    Calling sequence of f:
1046 $  f(TS ts,PetscReal t,Vec u,Vec u_t,Vec F,ctx);
1047 
1048 +  t   - time at step/stage being solved
1049 .  u   - state vector
1050 .  u_t - time derivative of state vector
1051 .  F   - function vector
1052 -  ctx - [optional] user-defined context for matrix evaluation routine
1053 
1054    Important:
1055    The user MUST call either this routine, TSSetRHSFunction().  This routine must be used when not solving an ODE, for example a DAE.
1056 
1057    Level: beginner
1058 
1059 .keywords: TS, timestep, set, DAE, Jacobian
1060 
1061 .seealso: TSSetRHSJacobian(), TSSetRHSFunction(), TSSetIJacobian()
1062 @*/
1063 PetscErrorCode  TSSetIFunction(TS ts,Vec res,TSIFunction f,void *ctx)
1064 {
1065   PetscErrorCode ierr;
1066   SNES           snes;
1067   Vec            resalloc = NULL;
1068   DM             dm;
1069 
1070   PetscFunctionBegin;
1071   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1072   if (res) PetscValidHeaderSpecific(res,VEC_CLASSID,2);
1073 
1074   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1075   ierr = DMTSSetIFunction(dm,f,ctx);CHKERRQ(ierr);
1076 
1077   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1078   if (!res && !ts->dm && ts->vec_sol) {
1079     ierr = VecDuplicate(ts->vec_sol,&resalloc);CHKERRQ(ierr);
1080     res  = resalloc;
1081   }
1082   ierr = SNESSetFunction(snes,res,SNESTSFormFunction,ts);CHKERRQ(ierr);
1083   ierr = VecDestroy(&resalloc);CHKERRQ(ierr);
1084   PetscFunctionReturn(0);
1085 }
1086 
1087 #undef __FUNCT__
1088 #define __FUNCT__ "TSGetIFunction"
1089 /*@C
1090    TSGetIFunction - Returns the vector where the implicit residual is stored and the function/contex to compute it.
1091 
1092    Not Collective
1093 
1094    Input Parameter:
1095 .  ts - the TS context
1096 
1097    Output Parameter:
1098 +  r - vector to hold residual (or NULL)
1099 .  func - the function to compute residual (or NULL)
1100 -  ctx - the function context (or NULL)
1101 
1102    Level: advanced
1103 
1104 .keywords: TS, nonlinear, get, function
1105 
1106 .seealso: TSSetIFunction(), SNESGetFunction()
1107 @*/
1108 PetscErrorCode TSGetIFunction(TS ts,Vec *r,TSIFunction *func,void **ctx)
1109 {
1110   PetscErrorCode ierr;
1111   SNES           snes;
1112   DM             dm;
1113 
1114   PetscFunctionBegin;
1115   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1116   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1117   ierr = SNESGetFunction(snes,r,NULL,NULL);CHKERRQ(ierr);
1118   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1119   ierr = DMTSGetIFunction(dm,func,ctx);CHKERRQ(ierr);
1120   PetscFunctionReturn(0);
1121 }
1122 
1123 #undef __FUNCT__
1124 #define __FUNCT__ "TSGetRHSFunction"
1125 /*@C
1126    TSGetRHSFunction - Returns the vector where the right hand side is stored and the function/context to compute it.
1127 
1128    Not Collective
1129 
1130    Input Parameter:
1131 .  ts - the TS context
1132 
1133    Output Parameter:
1134 +  r - vector to hold computed right hand side (or NULL)
1135 .  func - the function to compute right hand side (or NULL)
1136 -  ctx - the function context (or NULL)
1137 
1138    Level: advanced
1139 
1140 .keywords: TS, nonlinear, get, function
1141 
1142 .seealso: TSSetRhsfunction(), SNESGetFunction()
1143 @*/
1144 PetscErrorCode TSGetRHSFunction(TS ts,Vec *r,TSRHSFunction *func,void **ctx)
1145 {
1146   PetscErrorCode ierr;
1147   SNES           snes;
1148   DM             dm;
1149 
1150   PetscFunctionBegin;
1151   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1152   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1153   ierr = SNESGetFunction(snes,r,NULL,NULL);CHKERRQ(ierr);
1154   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1155   ierr = DMTSGetRHSFunction(dm,func,ctx);CHKERRQ(ierr);
1156   PetscFunctionReturn(0);
1157 }
1158 
1159 #undef __FUNCT__
1160 #define __FUNCT__ "TSSetIJacobian"
1161 /*@C
1162    TSSetIJacobian - Set the function to compute the matrix dF/dU + a*dF/dU_t where F(t,U,U_t) is the function
1163         provided with TSSetIFunction().
1164 
1165    Logically Collective on TS
1166 
1167    Input Parameters:
1168 +  ts  - the TS context obtained from TSCreate()
1169 .  Amat - (approximate) Jacobian matrix
1170 .  Pmat - matrix used to compute preconditioner (usually the same as Amat)
1171 .  f   - the Jacobian evaluation routine
1172 -  ctx - user-defined context for private data for the Jacobian evaluation routine (may be NULL)
1173 
1174    Calling sequence of f:
1175 $  f(TS ts,PetscReal t,Vec U,Vec U_t,PetscReal a,Mat Amat,Mat Pmat,void *ctx);
1176 
1177 +  t    - time at step/stage being solved
1178 .  U    - state vector
1179 .  U_t  - time derivative of state vector
1180 .  a    - shift
1181 .  Amat - (approximate) Jacobian of F(t,U,W+a*U), equivalent to dF/dU + a*dF/dU_t
1182 .  Pmat - matrix used for constructing preconditioner, usually the same as Amat
1183 -  ctx  - [optional] user-defined context for matrix evaluation routine
1184 
1185    Notes:
1186    The matrices Amat and Pmat are exactly the matrices that are used by SNES for the nonlinear solve.
1187 
1188    The matrix dF/dU + a*dF/dU_t you provide turns out to be
1189    the Jacobian of F(t,U,W+a*U) where F(t,U,U_t) = 0 is the DAE to be solved.
1190    The time integrator internally approximates U_t by W+a*U where the positive "shift"
1191    a and vector W depend on the integration method, step size, and past states. For example with
1192    the backward Euler method a = 1/dt and W = -a*U(previous timestep) so
1193    W + a*U = a*(U - U(previous timestep)) = (U - U(previous timestep))/dt
1194 
1195    Level: beginner
1196 
1197 .keywords: TS, timestep, DAE, Jacobian
1198 
1199 .seealso: TSSetIFunction(), TSSetRHSJacobian(), SNESComputeJacobianDefaultColor(), SNESComputeJacobianDefault(), TSSetRHSFunction()
1200 
1201 @*/
1202 PetscErrorCode  TSSetIJacobian(TS ts,Mat Amat,Mat Pmat,TSIJacobian f,void *ctx)
1203 {
1204   PetscErrorCode ierr;
1205   SNES           snes;
1206   DM             dm;
1207 
1208   PetscFunctionBegin;
1209   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1210   if (Amat) PetscValidHeaderSpecific(Amat,MAT_CLASSID,2);
1211   if (Pmat) PetscValidHeaderSpecific(Pmat,MAT_CLASSID,3);
1212   if (Amat) PetscCheckSameComm(ts,1,Amat,2);
1213   if (Pmat) PetscCheckSameComm(ts,1,Pmat,3);
1214 
1215   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1216   ierr = DMTSSetIJacobian(dm,f,ctx);CHKERRQ(ierr);
1217 
1218   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1219   ierr = SNESSetJacobian(snes,Amat,Pmat,SNESTSFormJacobian,ts);CHKERRQ(ierr);
1220   PetscFunctionReturn(0);
1221 }
1222 
1223 #undef __FUNCT__
1224 #define __FUNCT__ "TSRHSJacobianSetReuse"
1225 /*@
1226    TSRHSJacobianSetReuse - restore RHS Jacobian before re-evaluating.  Without this flag, TS will change the sign and
1227    shift the RHS Jacobian for a finite-time-step implicit solve, in which case the user function will need to recompute
1228    the entire Jacobian.  The reuse flag must be set if the evaluation function will assume that the matrix entries have
1229    not been changed by the TS.
1230 
1231    Logically Collective
1232 
1233    Input Arguments:
1234 +  ts - TS context obtained from TSCreate()
1235 -  reuse - PETSC_TRUE if the RHS Jacobian
1236 
1237    Level: intermediate
1238 
1239 .seealso: TSSetRHSJacobian(), TSComputeRHSJacobianConstant()
1240 @*/
1241 PetscErrorCode TSRHSJacobianSetReuse(TS ts,PetscBool reuse)
1242 {
1243   PetscFunctionBegin;
1244   ts->rhsjacobian.reuse = reuse;
1245   PetscFunctionReturn(0);
1246 }
1247 
1248 #undef __FUNCT__
1249 #define __FUNCT__ "TSLoad"
1250 /*@C
1251   TSLoad - Loads a KSP that has been stored in binary  with KSPView().
1252 
1253   Collective on PetscViewer
1254 
1255   Input Parameters:
1256 + newdm - the newly loaded TS, this needs to have been created with TSCreate() or
1257            some related function before a call to TSLoad().
1258 - viewer - binary file viewer, obtained from PetscViewerBinaryOpen()
1259 
1260    Level: intermediate
1261 
1262   Notes:
1263    The type is determined by the data in the file, any type set into the TS before this call is ignored.
1264 
1265   Notes for advanced users:
1266   Most users should not need to know the details of the binary storage
1267   format, since TSLoad() and TSView() completely hide these details.
1268   But for anyone who's interested, the standard binary matrix storage
1269   format is
1270 .vb
1271      has not yet been determined
1272 .ve
1273 
1274 .seealso: PetscViewerBinaryOpen(), TSView(), MatLoad(), VecLoad()
1275 @*/
1276 PetscErrorCode  TSLoad(TS ts, PetscViewer viewer)
1277 {
1278   PetscErrorCode ierr;
1279   PetscBool      isbinary;
1280   PetscInt       classid;
1281   char           type[256];
1282   DMTS           sdm;
1283   DM             dm;
1284 
1285   PetscFunctionBegin;
1286   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1287   PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,2);
1288   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);CHKERRQ(ierr);
1289   if (!isbinary) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Invalid viewer; open viewer with PetscViewerBinaryOpen()");
1290 
1291   ierr = PetscViewerBinaryRead(viewer,&classid,1,PETSC_INT);CHKERRQ(ierr);
1292   if (classid != TS_FILE_CLASSID) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_ARG_WRONG,"Not TS next in file");
1293   ierr = PetscViewerBinaryRead(viewer,type,256,PETSC_CHAR);CHKERRQ(ierr);
1294   ierr = TSSetType(ts, type);CHKERRQ(ierr);
1295   if (ts->ops->load) {
1296     ierr = (*ts->ops->load)(ts,viewer);CHKERRQ(ierr);
1297   }
1298   ierr = DMCreate(PetscObjectComm((PetscObject)ts),&dm);CHKERRQ(ierr);
1299   ierr = DMLoad(dm,viewer);CHKERRQ(ierr);
1300   ierr = TSSetDM(ts,dm);CHKERRQ(ierr);
1301   ierr = DMCreateGlobalVector(ts->dm,&ts->vec_sol);CHKERRQ(ierr);
1302   ierr = VecLoad(ts->vec_sol,viewer);CHKERRQ(ierr);
1303   ierr = DMGetDMTS(ts->dm,&sdm);CHKERRQ(ierr);
1304   ierr = DMTSLoad(sdm,viewer);CHKERRQ(ierr);
1305   PetscFunctionReturn(0);
1306 }
1307 
1308 #include <petscdraw.h>
1309 #if defined(PETSC_HAVE_SAWS)
1310 #include <petscviewersaws.h>
1311 #endif
1312 #undef __FUNCT__
1313 #define __FUNCT__ "TSView"
1314 /*@C
1315     TSView - Prints the TS data structure.
1316 
1317     Collective on TS
1318 
1319     Input Parameters:
1320 +   ts - the TS context obtained from TSCreate()
1321 -   viewer - visualization context
1322 
1323     Options Database Key:
1324 .   -ts_view - calls TSView() at end of TSStep()
1325 
1326     Notes:
1327     The available visualization contexts include
1328 +     PETSC_VIEWER_STDOUT_SELF - standard output (default)
1329 -     PETSC_VIEWER_STDOUT_WORLD - synchronized standard
1330          output where only the first processor opens
1331          the file.  All other processors send their
1332          data to the first processor to print.
1333 
1334     The user can open an alternative visualization context with
1335     PetscViewerASCIIOpen() - output to a specified file.
1336 
1337     Level: beginner
1338 
1339 .keywords: TS, timestep, view
1340 
1341 .seealso: PetscViewerASCIIOpen()
1342 @*/
1343 PetscErrorCode  TSView(TS ts,PetscViewer viewer)
1344 {
1345   PetscErrorCode ierr;
1346   TSType         type;
1347   PetscBool      iascii,isstring,isundials,isbinary,isdraw;
1348   DMTS           sdm;
1349 #if defined(PETSC_HAVE_SAWS)
1350   PetscBool      isams;
1351 #endif
1352 
1353   PetscFunctionBegin;
1354   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1355   if (!viewer) {
1356     ierr = PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)ts),&viewer);CHKERRQ(ierr);
1357   }
1358   PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,2);
1359   PetscCheckSameComm(ts,1,viewer,2);
1360 
1361   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr);
1362   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);CHKERRQ(ierr);
1363   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);CHKERRQ(ierr);
1364   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);CHKERRQ(ierr);
1365 #if defined(PETSC_HAVE_SAWS)
1366   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSAWS,&isams);CHKERRQ(ierr);
1367 #endif
1368   if (iascii) {
1369     ierr = PetscObjectPrintClassNamePrefixType((PetscObject)ts,viewer);CHKERRQ(ierr);
1370     ierr = PetscViewerASCIIPrintf(viewer,"  maximum steps=%D\n",ts->max_steps);CHKERRQ(ierr);
1371     ierr = PetscViewerASCIIPrintf(viewer,"  maximum time=%g\n",(double)ts->max_time);CHKERRQ(ierr);
1372     if (ts->problem_type == TS_NONLINEAR) {
1373       ierr = PetscViewerASCIIPrintf(viewer,"  total number of nonlinear solver iterations=%D\n",ts->snes_its);CHKERRQ(ierr);
1374       ierr = PetscViewerASCIIPrintf(viewer,"  total number of nonlinear solve failures=%D\n",ts->num_snes_failures);CHKERRQ(ierr);
1375     }
1376     ierr = PetscViewerASCIIPrintf(viewer,"  total number of linear solver iterations=%D\n",ts->ksp_its);CHKERRQ(ierr);
1377     ierr = PetscViewerASCIIPrintf(viewer,"  total number of rejected steps=%D\n",ts->reject);CHKERRQ(ierr);
1378     ierr = DMGetDMTS(ts->dm,&sdm);CHKERRQ(ierr);
1379     ierr = DMTSView(sdm,viewer);CHKERRQ(ierr);
1380     if (ts->ops->view) {
1381       ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
1382       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1383       ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
1384     }
1385   } else if (isstring) {
1386     ierr = TSGetType(ts,&type);CHKERRQ(ierr);
1387     ierr = PetscViewerStringSPrintf(viewer," %-7.7s",type);CHKERRQ(ierr);
1388   } else if (isbinary) {
1389     PetscInt    classid = TS_FILE_CLASSID;
1390     MPI_Comm    comm;
1391     PetscMPIInt rank;
1392     char        type[256];
1393 
1394     ierr = PetscObjectGetComm((PetscObject)ts,&comm);CHKERRQ(ierr);
1395     ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
1396     if (!rank) {
1397       ierr = PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT,PETSC_FALSE);CHKERRQ(ierr);
1398       ierr = PetscStrncpy(type,((PetscObject)ts)->type_name,256);CHKERRQ(ierr);
1399       ierr = PetscViewerBinaryWrite(viewer,type,256,PETSC_CHAR,PETSC_FALSE);CHKERRQ(ierr);
1400     }
1401     if (ts->ops->view) {
1402       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1403     }
1404     ierr = DMView(ts->dm,viewer);CHKERRQ(ierr);
1405     ierr = VecView(ts->vec_sol,viewer);CHKERRQ(ierr);
1406     ierr = DMGetDMTS(ts->dm,&sdm);CHKERRQ(ierr);
1407     ierr = DMTSView(sdm,viewer);CHKERRQ(ierr);
1408   } else if (isdraw) {
1409     PetscDraw draw;
1410     char      str[36];
1411     PetscReal x,y,bottom,h;
1412 
1413     ierr   = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr);
1414     ierr   = PetscDrawGetCurrentPoint(draw,&x,&y);CHKERRQ(ierr);
1415     ierr   = PetscStrcpy(str,"TS: ");CHKERRQ(ierr);
1416     ierr   = PetscStrcat(str,((PetscObject)ts)->type_name);CHKERRQ(ierr);
1417     ierr   = PetscDrawBoxedString(draw,x,y,PETSC_DRAW_BLACK,PETSC_DRAW_BLACK,str,NULL,&h);CHKERRQ(ierr);
1418     bottom = y - h;
1419     ierr   = PetscDrawPushCurrentPoint(draw,x,bottom);CHKERRQ(ierr);
1420     if (ts->ops->view) {
1421       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1422     }
1423     ierr = PetscDrawPopCurrentPoint(draw);CHKERRQ(ierr);
1424 #if defined(PETSC_HAVE_SAWS)
1425   } else if (isams) {
1426     PetscMPIInt rank;
1427     const char  *name;
1428 
1429     ierr = PetscObjectGetName((PetscObject)ts,&name);CHKERRQ(ierr);
1430     ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRQ(ierr);
1431     if (!((PetscObject)ts)->amsmem && !rank) {
1432       char       dir[1024];
1433 
1434       ierr = PetscObjectViewSAWs((PetscObject)ts,viewer);CHKERRQ(ierr);
1435       ierr = PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/time_step",name);CHKERRQ(ierr);
1436       PetscStackCallSAWs(SAWs_Register,(dir,&ts->steps,1,SAWs_READ,SAWs_INT));
1437       ierr = PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/time",name);CHKERRQ(ierr);
1438       PetscStackCallSAWs(SAWs_Register,(dir,&ts->ptime,1,SAWs_READ,SAWs_DOUBLE));
1439     }
1440     if (ts->ops->view) {
1441       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1442     }
1443 #endif
1444   }
1445 
1446   ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
1447   ierr = PetscObjectTypeCompare((PetscObject)ts,TSSUNDIALS,&isundials);CHKERRQ(ierr);
1448   ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
1449   PetscFunctionReturn(0);
1450 }
1451 
1452 
1453 #undef __FUNCT__
1454 #define __FUNCT__ "TSSetApplicationContext"
1455 /*@
1456    TSSetApplicationContext - Sets an optional user-defined context for
1457    the timesteppers.
1458 
1459    Logically Collective on TS
1460 
1461    Input Parameters:
1462 +  ts - the TS context obtained from TSCreate()
1463 -  usrP - optional user context
1464 
1465    Level: intermediate
1466 
1467 .keywords: TS, timestep, set, application, context
1468 
1469 .seealso: TSGetApplicationContext()
1470 @*/
1471 PetscErrorCode  TSSetApplicationContext(TS ts,void *usrP)
1472 {
1473   PetscFunctionBegin;
1474   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1475   ts->user = usrP;
1476   PetscFunctionReturn(0);
1477 }
1478 
1479 #undef __FUNCT__
1480 #define __FUNCT__ "TSGetApplicationContext"
1481 /*@
1482     TSGetApplicationContext - Gets the user-defined context for the
1483     timestepper.
1484 
1485     Not Collective
1486 
1487     Input Parameter:
1488 .   ts - the TS context obtained from TSCreate()
1489 
1490     Output Parameter:
1491 .   usrP - user context
1492 
1493     Level: intermediate
1494 
1495 .keywords: TS, timestep, get, application, context
1496 
1497 .seealso: TSSetApplicationContext()
1498 @*/
1499 PetscErrorCode  TSGetApplicationContext(TS ts,void *usrP)
1500 {
1501   PetscFunctionBegin;
1502   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1503   *(void**)usrP = ts->user;
1504   PetscFunctionReturn(0);
1505 }
1506 
1507 #undef __FUNCT__
1508 #define __FUNCT__ "TSGetTimeStepNumber"
1509 /*@
1510    TSGetTimeStepNumber - Gets the number of time steps completed.
1511 
1512    Not Collective
1513 
1514    Input Parameter:
1515 .  ts - the TS context obtained from TSCreate()
1516 
1517    Output Parameter:
1518 .  iter - number of steps completed so far
1519 
1520    Level: intermediate
1521 
1522 .keywords: TS, timestep, get, iteration, number
1523 .seealso: TSGetTime(), TSGetTimeStep(), TSSetPreStep(), TSSetPreStage(), TSSetPostStage(), TSSetPostStep()
1524 @*/
1525 PetscErrorCode  TSGetTimeStepNumber(TS ts,PetscInt *iter)
1526 {
1527   PetscFunctionBegin;
1528   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1529   PetscValidIntPointer(iter,2);
1530   *iter = ts->steps;
1531   PetscFunctionReturn(0);
1532 }
1533 
1534 #undef __FUNCT__
1535 #define __FUNCT__ "TSSetInitialTimeStep"
1536 /*@
1537    TSSetInitialTimeStep - Sets the initial timestep to be used,
1538    as well as the initial time.
1539 
1540    Logically Collective on TS
1541 
1542    Input Parameters:
1543 +  ts - the TS context obtained from TSCreate()
1544 .  initial_time - the initial time
1545 -  time_step - the size of the timestep
1546 
1547    Level: intermediate
1548 
1549 .seealso: TSSetTimeStep(), TSGetTimeStep()
1550 
1551 .keywords: TS, set, initial, timestep
1552 @*/
1553 PetscErrorCode  TSSetInitialTimeStep(TS ts,PetscReal initial_time,PetscReal time_step)
1554 {
1555   PetscErrorCode ierr;
1556 
1557   PetscFunctionBegin;
1558   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1559   ierr = TSSetTimeStep(ts,time_step);CHKERRQ(ierr);
1560   ierr = TSSetTime(ts,initial_time);CHKERRQ(ierr);
1561   PetscFunctionReturn(0);
1562 }
1563 
1564 #undef __FUNCT__
1565 #define __FUNCT__ "TSSetTimeStep"
1566 /*@
1567    TSSetTimeStep - Allows one to reset the timestep at any time,
1568    useful for simple pseudo-timestepping codes.
1569 
1570    Logically Collective on TS
1571 
1572    Input Parameters:
1573 +  ts - the TS context obtained from TSCreate()
1574 -  time_step - the size of the timestep
1575 
1576    Level: intermediate
1577 
1578 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
1579 
1580 .keywords: TS, set, timestep
1581 @*/
1582 PetscErrorCode  TSSetTimeStep(TS ts,PetscReal time_step)
1583 {
1584   PetscFunctionBegin;
1585   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1586   PetscValidLogicalCollectiveReal(ts,time_step,2);
1587   ts->time_step      = time_step;
1588   ts->time_step_orig = time_step;
1589   PetscFunctionReturn(0);
1590 }
1591 
1592 #undef __FUNCT__
1593 #define __FUNCT__ "TSSetExactFinalTime"
1594 /*@
1595    TSSetExactFinalTime - Determines whether to adapt the final time step to
1596      match the exact final time, interpolate solution to the exact final time,
1597      or just return at the final time TS computed.
1598 
1599   Logically Collective on TS
1600 
1601    Input Parameter:
1602 +   ts - the time-step context
1603 -   eftopt - exact final time option
1604 
1605    Level: beginner
1606 
1607 .seealso: TSExactFinalTimeOption
1608 @*/
1609 PetscErrorCode  TSSetExactFinalTime(TS ts,TSExactFinalTimeOption eftopt)
1610 {
1611   PetscFunctionBegin;
1612   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1613   PetscValidLogicalCollectiveEnum(ts,eftopt,2);
1614   ts->exact_final_time = eftopt;
1615   PetscFunctionReturn(0);
1616 }
1617 
1618 #undef __FUNCT__
1619 #define __FUNCT__ "TSGetTimeStep"
1620 /*@
1621    TSGetTimeStep - Gets the current timestep size.
1622 
1623    Not Collective
1624 
1625    Input Parameter:
1626 .  ts - the TS context obtained from TSCreate()
1627 
1628    Output Parameter:
1629 .  dt - the current timestep size
1630 
1631    Level: intermediate
1632 
1633 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
1634 
1635 .keywords: TS, get, timestep
1636 @*/
1637 PetscErrorCode  TSGetTimeStep(TS ts,PetscReal *dt)
1638 {
1639   PetscFunctionBegin;
1640   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1641   PetscValidRealPointer(dt,2);
1642   *dt = ts->time_step;
1643   PetscFunctionReturn(0);
1644 }
1645 
1646 #undef __FUNCT__
1647 #define __FUNCT__ "TSGetSolution"
1648 /*@
1649    TSGetSolution - Returns the solution at the present timestep. It
1650    is valid to call this routine inside the function that you are evaluating
1651    in order to move to the new timestep. This vector not changed until
1652    the solution at the next timestep has been calculated.
1653 
1654    Not Collective, but Vec returned is parallel if TS is parallel
1655 
1656    Input Parameter:
1657 .  ts - the TS context obtained from TSCreate()
1658 
1659    Output Parameter:
1660 .  v - the vector containing the solution
1661 
1662    Level: intermediate
1663 
1664 .seealso: TSGetTimeStep()
1665 
1666 .keywords: TS, timestep, get, solution
1667 @*/
1668 PetscErrorCode  TSGetSolution(TS ts,Vec *v)
1669 {
1670   PetscFunctionBegin;
1671   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1672   PetscValidPointer(v,2);
1673   *v = ts->vec_sol;
1674   PetscFunctionReturn(0);
1675 }
1676 
1677 /* ----- Routines to initialize and destroy a timestepper ---- */
1678 #undef __FUNCT__
1679 #define __FUNCT__ "TSSetProblemType"
1680 /*@
1681   TSSetProblemType - Sets the type of problem to be solved.
1682 
1683   Not collective
1684 
1685   Input Parameters:
1686 + ts   - The TS
1687 - type - One of TS_LINEAR, TS_NONLINEAR where these types refer to problems of the forms
1688 .vb
1689          U_t - A U = 0      (linear)
1690          U_t - A(t) U = 0   (linear)
1691          F(t,U,U_t) = 0     (nonlinear)
1692 .ve
1693 
1694    Level: beginner
1695 
1696 .keywords: TS, problem type
1697 .seealso: TSSetUp(), TSProblemType, TS
1698 @*/
1699 PetscErrorCode  TSSetProblemType(TS ts, TSProblemType type)
1700 {
1701   PetscErrorCode ierr;
1702 
1703   PetscFunctionBegin;
1704   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
1705   ts->problem_type = type;
1706   if (type == TS_LINEAR) {
1707     SNES snes;
1708     ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1709     ierr = SNESSetType(snes,SNESKSPONLY);CHKERRQ(ierr);
1710   }
1711   PetscFunctionReturn(0);
1712 }
1713 
1714 #undef __FUNCT__
1715 #define __FUNCT__ "TSGetProblemType"
1716 /*@C
1717   TSGetProblemType - Gets the type of problem to be solved.
1718 
1719   Not collective
1720 
1721   Input Parameter:
1722 . ts   - The TS
1723 
1724   Output Parameter:
1725 . type - One of TS_LINEAR, TS_NONLINEAR where these types refer to problems of the forms
1726 .vb
1727          M U_t = A U
1728          M(t) U_t = A(t) U
1729          F(t,U,U_t)
1730 .ve
1731 
1732    Level: beginner
1733 
1734 .keywords: TS, problem type
1735 .seealso: TSSetUp(), TSProblemType, TS
1736 @*/
1737 PetscErrorCode  TSGetProblemType(TS ts, TSProblemType *type)
1738 {
1739   PetscFunctionBegin;
1740   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
1741   PetscValidIntPointer(type,2);
1742   *type = ts->problem_type;
1743   PetscFunctionReturn(0);
1744 }
1745 
1746 #undef __FUNCT__
1747 #define __FUNCT__ "TSSetUp"
1748 /*@
1749    TSSetUp - Sets up the internal data structures for the later use
1750    of a timestepper.
1751 
1752    Collective on TS
1753 
1754    Input Parameter:
1755 .  ts - the TS context obtained from TSCreate()
1756 
1757    Notes:
1758    For basic use of the TS solvers the user need not explicitly call
1759    TSSetUp(), since these actions will automatically occur during
1760    the call to TSStep().  However, if one wishes to control this
1761    phase separately, TSSetUp() should be called after TSCreate()
1762    and optional routines of the form TSSetXXX(), but before TSStep().
1763 
1764    Level: advanced
1765 
1766 .keywords: TS, timestep, setup
1767 
1768 .seealso: TSCreate(), TSStep(), TSDestroy()
1769 @*/
1770 PetscErrorCode  TSSetUp(TS ts)
1771 {
1772   PetscErrorCode ierr;
1773   DM             dm;
1774   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
1775   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*);
1776   TSIJacobian    ijac;
1777   TSRHSJacobian  rhsjac;
1778 
1779   PetscFunctionBegin;
1780   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1781   if (ts->setupcalled) PetscFunctionReturn(0);
1782 
1783   if (!((PetscObject)ts)->type_name) {
1784     ierr = TSSetType(ts,TSEULER);CHKERRQ(ierr);
1785   }
1786 
1787   if (!ts->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Must call TSSetSolution() first");
1788 
1789   ierr = TSGetAdapt(ts,&ts->adapt);CHKERRQ(ierr);
1790 
1791   if (ts->rhsjacobian.reuse) {
1792     Mat Amat,Pmat;
1793     SNES snes;
1794     ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1795     ierr = SNESGetJacobian(snes,&Amat,&Pmat,NULL,NULL);CHKERRQ(ierr);
1796     /* Matching matrices implies that an IJacobian is NOT set, because if it had been set, the IJacobian's matrix would
1797      * have displaced the RHS matrix */
1798     if (Amat == ts->Arhs) {
1799       ierr = MatDuplicate(ts->Arhs,MAT_DO_NOT_COPY_VALUES,&Amat);CHKERRQ(ierr);
1800       ierr = SNESSetJacobian(snes,Amat,NULL,NULL,NULL);CHKERRQ(ierr);
1801       ierr = MatDestroy(&Amat);CHKERRQ(ierr);
1802     }
1803     if (Pmat == ts->Brhs) {
1804       ierr = MatDuplicate(ts->Brhs,MAT_DO_NOT_COPY_VALUES,&Pmat);CHKERRQ(ierr);
1805       ierr = SNESSetJacobian(snes,NULL,Pmat,NULL,NULL);CHKERRQ(ierr);
1806       ierr = MatDestroy(&Pmat);CHKERRQ(ierr);
1807     }
1808   }
1809 
1810   if (ts->ops->setup) {
1811     ierr = (*ts->ops->setup)(ts);CHKERRQ(ierr);
1812   }
1813 
1814   /* in the case where we've set a DMTSFunction or what have you, we need the default SNESFunction
1815    to be set right but can't do it elsewhere due to the overreliance on ctx=ts.
1816    */
1817   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1818   ierr = DMSNESGetFunction(dm,&func,NULL);CHKERRQ(ierr);
1819   if (!func) {
1820     ierr =DMSNESSetFunction(dm,SNESTSFormFunction,ts);CHKERRQ(ierr);
1821   }
1822   /* if the SNES doesn't have a jacobian set and the TS has an ijacobian or rhsjacobian set, set the SNES to use it.
1823      Otherwise, the SNES will use coloring internally to form the Jacobian.
1824    */
1825   ierr = DMSNESGetJacobian(dm,&jac,NULL);CHKERRQ(ierr);
1826   ierr = DMTSGetIJacobian(dm,&ijac,NULL);CHKERRQ(ierr);
1827   ierr = DMTSGetRHSJacobian(dm,&rhsjac,NULL);CHKERRQ(ierr);
1828   if (!jac && (ijac || rhsjac)) {
1829     ierr = DMSNESSetJacobian(dm,SNESTSFormJacobian,ts);CHKERRQ(ierr);
1830   }
1831   ts->setupcalled = PETSC_TRUE;
1832   PetscFunctionReturn(0);
1833 }
1834 
1835 #undef __FUNCT__
1836 #define __FUNCT__ "TSReset"
1837 /*@
1838    TSReset - Resets a TS context and removes any allocated Vecs and Mats.
1839 
1840    Collective on TS
1841 
1842    Input Parameter:
1843 .  ts - the TS context obtained from TSCreate()
1844 
1845    Level: beginner
1846 
1847 .keywords: TS, timestep, reset
1848 
1849 .seealso: TSCreate(), TSSetup(), TSDestroy()
1850 @*/
1851 PetscErrorCode  TSReset(TS ts)
1852 {
1853   PetscErrorCode ierr;
1854 
1855   PetscFunctionBegin;
1856   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1857   if (ts->ops->reset) {
1858     ierr = (*ts->ops->reset)(ts);CHKERRQ(ierr);
1859   }
1860   if (ts->snes) {ierr = SNESReset(ts->snes);CHKERRQ(ierr);}
1861 
1862   ierr = MatDestroy(&ts->Arhs);CHKERRQ(ierr);
1863   ierr = MatDestroy(&ts->Brhs);CHKERRQ(ierr);
1864   ierr = VecDestroy(&ts->Frhs);CHKERRQ(ierr);
1865   ierr = VecDestroy(&ts->vec_sol);CHKERRQ(ierr);
1866   ierr = VecDestroy(&ts->vatol);CHKERRQ(ierr);
1867   ierr = VecDestroy(&ts->vrtol);CHKERRQ(ierr);
1868   ierr = VecDestroyVecs(ts->nwork,&ts->work);CHKERRQ(ierr);
1869 
1870   ts->setupcalled = PETSC_FALSE;
1871   PetscFunctionReturn(0);
1872 }
1873 
1874 #undef __FUNCT__
1875 #define __FUNCT__ "TSDestroy"
1876 /*@
1877    TSDestroy - Destroys the timestepper context that was created
1878    with TSCreate().
1879 
1880    Collective on TS
1881 
1882    Input Parameter:
1883 .  ts - the TS context obtained from TSCreate()
1884 
1885    Level: beginner
1886 
1887 .keywords: TS, timestepper, destroy
1888 
1889 .seealso: TSCreate(), TSSetUp(), TSSolve()
1890 @*/
1891 PetscErrorCode  TSDestroy(TS *ts)
1892 {
1893   PetscErrorCode ierr;
1894 
1895   PetscFunctionBegin;
1896   if (!*ts) PetscFunctionReturn(0);
1897   PetscValidHeaderSpecific((*ts),TS_CLASSID,1);
1898   if (--((PetscObject)(*ts))->refct > 0) {*ts = 0; PetscFunctionReturn(0);}
1899 
1900   ierr = TSReset((*ts));CHKERRQ(ierr);
1901 
1902   /* if memory was published with SAWs then destroy it */
1903   ierr = PetscObjectSAWsViewOff((PetscObject)*ts);CHKERRQ(ierr);
1904   if ((*ts)->ops->destroy) {ierr = (*(*ts)->ops->destroy)((*ts));CHKERRQ(ierr);}
1905 
1906   ierr = TSAdaptDestroy(&(*ts)->adapt);CHKERRQ(ierr);
1907   if ((*ts)->event) {
1908     ierr = TSEventMonitorDestroy(&(*ts)->event);CHKERRQ(ierr);
1909   }
1910   ierr = SNESDestroy(&(*ts)->snes);CHKERRQ(ierr);
1911   ierr = DMDestroy(&(*ts)->dm);CHKERRQ(ierr);
1912   ierr = TSMonitorCancel((*ts));CHKERRQ(ierr);
1913 
1914   ierr = PetscHeaderDestroy(ts);CHKERRQ(ierr);
1915   PetscFunctionReturn(0);
1916 }
1917 
1918 #undef __FUNCT__
1919 #define __FUNCT__ "TSGetSNES"
1920 /*@
1921    TSGetSNES - Returns the SNES (nonlinear solver) associated with
1922    a TS (timestepper) context. Valid only for nonlinear problems.
1923 
1924    Not Collective, but SNES is parallel if TS is parallel
1925 
1926    Input Parameter:
1927 .  ts - the TS context obtained from TSCreate()
1928 
1929    Output Parameter:
1930 .  snes - the nonlinear solver context
1931 
1932    Notes:
1933    The user can then directly manipulate the SNES context to set various
1934    options, etc.  Likewise, the user can then extract and manipulate the
1935    KSP, KSP, and PC contexts as well.
1936 
1937    TSGetSNES() does not work for integrators that do not use SNES; in
1938    this case TSGetSNES() returns NULL in snes.
1939 
1940    Level: beginner
1941 
1942 .keywords: timestep, get, SNES
1943 @*/
1944 PetscErrorCode  TSGetSNES(TS ts,SNES *snes)
1945 {
1946   PetscErrorCode ierr;
1947 
1948   PetscFunctionBegin;
1949   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1950   PetscValidPointer(snes,2);
1951   if (!ts->snes) {
1952     ierr = SNESCreate(PetscObjectComm((PetscObject)ts),&ts->snes);CHKERRQ(ierr);
1953     ierr = SNESSetFunction(ts->snes,NULL,SNESTSFormFunction,ts);CHKERRQ(ierr);
1954     ierr = PetscLogObjectParent((PetscObject)ts,(PetscObject)ts->snes);CHKERRQ(ierr);
1955     ierr = PetscObjectIncrementTabLevel((PetscObject)ts->snes,(PetscObject)ts,1);CHKERRQ(ierr);
1956     if (ts->dm) {ierr = SNESSetDM(ts->snes,ts->dm);CHKERRQ(ierr);}
1957     if (ts->problem_type == TS_LINEAR) {
1958       ierr = SNESSetType(ts->snes,SNESKSPONLY);CHKERRQ(ierr);
1959     }
1960   }
1961   *snes = ts->snes;
1962   PetscFunctionReturn(0);
1963 }
1964 
1965 #undef __FUNCT__
1966 #define __FUNCT__ "TSSetSNES"
1967 /*@
1968    TSSetSNES - Set the SNES (nonlinear solver) to be used by the timestepping context
1969 
1970    Collective
1971 
1972    Input Parameter:
1973 +  ts - the TS context obtained from TSCreate()
1974 -  snes - the nonlinear solver context
1975 
1976    Notes:
1977    Most users should have the TS created by calling TSGetSNES()
1978 
1979    Level: developer
1980 
1981 .keywords: timestep, set, SNES
1982 @*/
1983 PetscErrorCode TSSetSNES(TS ts,SNES snes)
1984 {
1985   PetscErrorCode ierr;
1986   PetscErrorCode (*func)(SNES,Vec,Mat,Mat,void*);
1987 
1988   PetscFunctionBegin;
1989   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1990   PetscValidHeaderSpecific(snes,SNES_CLASSID,2);
1991   ierr = PetscObjectReference((PetscObject)snes);CHKERRQ(ierr);
1992   ierr = SNESDestroy(&ts->snes);CHKERRQ(ierr);
1993 
1994   ts->snes = snes;
1995 
1996   ierr = SNESSetFunction(ts->snes,NULL,SNESTSFormFunction,ts);CHKERRQ(ierr);
1997   ierr = SNESGetJacobian(ts->snes,NULL,NULL,&func,NULL);CHKERRQ(ierr);
1998   if (func == SNESTSFormJacobian) {
1999     ierr = SNESSetJacobian(ts->snes,NULL,NULL,SNESTSFormJacobian,ts);CHKERRQ(ierr);
2000   }
2001   PetscFunctionReturn(0);
2002 }
2003 
2004 #undef __FUNCT__
2005 #define __FUNCT__ "TSGetKSP"
2006 /*@
2007    TSGetKSP - Returns the KSP (linear solver) associated with
2008    a TS (timestepper) context.
2009 
2010    Not Collective, but KSP is parallel if TS is parallel
2011 
2012    Input Parameter:
2013 .  ts - the TS context obtained from TSCreate()
2014 
2015    Output Parameter:
2016 .  ksp - the nonlinear solver context
2017 
2018    Notes:
2019    The user can then directly manipulate the KSP context to set various
2020    options, etc.  Likewise, the user can then extract and manipulate the
2021    KSP and PC contexts as well.
2022 
2023    TSGetKSP() does not work for integrators that do not use KSP;
2024    in this case TSGetKSP() returns NULL in ksp.
2025 
2026    Level: beginner
2027 
2028 .keywords: timestep, get, KSP
2029 @*/
2030 PetscErrorCode  TSGetKSP(TS ts,KSP *ksp)
2031 {
2032   PetscErrorCode ierr;
2033   SNES           snes;
2034 
2035   PetscFunctionBegin;
2036   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2037   PetscValidPointer(ksp,2);
2038   if (!((PetscObject)ts)->type_name) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"KSP is not created yet. Call TSSetType() first");
2039   if (ts->problem_type != TS_LINEAR) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Linear only; use TSGetSNES()");
2040   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2041   ierr = SNESGetKSP(snes,ksp);CHKERRQ(ierr);
2042   PetscFunctionReturn(0);
2043 }
2044 
2045 /* ----------- Routines to set solver parameters ---------- */
2046 
2047 #undef __FUNCT__
2048 #define __FUNCT__ "TSGetDuration"
2049 /*@
2050    TSGetDuration - Gets the maximum number of timesteps to use and
2051    maximum time for iteration.
2052 
2053    Not Collective
2054 
2055    Input Parameters:
2056 +  ts       - the TS context obtained from TSCreate()
2057 .  maxsteps - maximum number of iterations to use, or NULL
2058 -  maxtime  - final time to iterate to, or NULL
2059 
2060    Level: intermediate
2061 
2062 .keywords: TS, timestep, get, maximum, iterations, time
2063 @*/
2064 PetscErrorCode  TSGetDuration(TS ts, PetscInt *maxsteps, PetscReal *maxtime)
2065 {
2066   PetscFunctionBegin;
2067   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2068   if (maxsteps) {
2069     PetscValidIntPointer(maxsteps,2);
2070     *maxsteps = ts->max_steps;
2071   }
2072   if (maxtime) {
2073     PetscValidScalarPointer(maxtime,3);
2074     *maxtime = ts->max_time;
2075   }
2076   PetscFunctionReturn(0);
2077 }
2078 
2079 #undef __FUNCT__
2080 #define __FUNCT__ "TSSetDuration"
2081 /*@
2082    TSSetDuration - Sets the maximum number of timesteps to use and
2083    maximum time for iteration.
2084 
2085    Logically Collective on TS
2086 
2087    Input Parameters:
2088 +  ts - the TS context obtained from TSCreate()
2089 .  maxsteps - maximum number of iterations to use
2090 -  maxtime - final time to iterate to
2091 
2092    Options Database Keys:
2093 .  -ts_max_steps <maxsteps> - Sets maxsteps
2094 .  -ts_final_time <maxtime> - Sets maxtime
2095 
2096    Notes:
2097    The default maximum number of iterations is 5000. Default time is 5.0
2098 
2099    Level: intermediate
2100 
2101 .keywords: TS, timestep, set, maximum, iterations
2102 
2103 .seealso: TSSetExactFinalTime()
2104 @*/
2105 PetscErrorCode  TSSetDuration(TS ts,PetscInt maxsteps,PetscReal maxtime)
2106 {
2107   PetscFunctionBegin;
2108   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2109   PetscValidLogicalCollectiveInt(ts,maxsteps,2);
2110   PetscValidLogicalCollectiveReal(ts,maxtime,2);
2111   if (maxsteps >= 0) ts->max_steps = maxsteps;
2112   if (maxtime != PETSC_DEFAULT) ts->max_time = maxtime;
2113   PetscFunctionReturn(0);
2114 }
2115 
2116 #undef __FUNCT__
2117 #define __FUNCT__ "TSSetSolution"
2118 /*@
2119    TSSetSolution - Sets the initial solution vector
2120    for use by the TS routines.
2121 
2122    Logically Collective on TS and Vec
2123 
2124    Input Parameters:
2125 +  ts - the TS context obtained from TSCreate()
2126 -  u - the solution vector
2127 
2128    Level: beginner
2129 
2130 .keywords: TS, timestep, set, solution, initial conditions
2131 @*/
2132 PetscErrorCode  TSSetSolution(TS ts,Vec u)
2133 {
2134   PetscErrorCode ierr;
2135   DM             dm;
2136 
2137   PetscFunctionBegin;
2138   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2139   PetscValidHeaderSpecific(u,VEC_CLASSID,2);
2140   ierr = PetscObjectReference((PetscObject)u);CHKERRQ(ierr);
2141   ierr = VecDestroy(&ts->vec_sol);CHKERRQ(ierr);
2142 
2143   ts->vec_sol = u;
2144 
2145   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
2146   ierr = DMShellSetGlobalVector(dm,u);CHKERRQ(ierr);
2147   PetscFunctionReturn(0);
2148 }
2149 
2150 #undef __FUNCT__
2151 #define __FUNCT__ "TSSetPreStep"
2152 /*@C
2153   TSSetPreStep - Sets the general-purpose function
2154   called once at the beginning of each time step.
2155 
2156   Logically Collective on TS
2157 
2158   Input Parameters:
2159 + ts   - The TS context obtained from TSCreate()
2160 - func - The function
2161 
2162   Calling sequence of func:
2163 . func (TS ts);
2164 
2165   Level: intermediate
2166 
2167   Note:
2168   If a step is rejected, TSStep() will call this routine again before each attempt.
2169   The last completed time step number can be queried using TSGetTimeStepNumber(), the
2170   size of the step being attempted can be obtained using TSGetTimeStep().
2171 
2172 .keywords: TS, timestep
2173 .seealso: TSSetPreStage(), TSSetPostStage(), TSSetPostStep(), TSStep()
2174 @*/
2175 PetscErrorCode  TSSetPreStep(TS ts, PetscErrorCode (*func)(TS))
2176 {
2177   PetscFunctionBegin;
2178   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2179   ts->prestep = func;
2180   PetscFunctionReturn(0);
2181 }
2182 
2183 #undef __FUNCT__
2184 #define __FUNCT__ "TSPreStep"
2185 /*@
2186   TSPreStep - Runs the user-defined pre-step function.
2187 
2188   Collective on TS
2189 
2190   Input Parameters:
2191 . ts   - The TS context obtained from TSCreate()
2192 
2193   Notes:
2194   TSPreStep() is typically used within time stepping implementations,
2195   so most users would not generally call this routine themselves.
2196 
2197   Level: developer
2198 
2199 .keywords: TS, timestep
2200 .seealso: TSSetPreStep(), TSPreStage(), TSPostStage(), TSPostStep()
2201 @*/
2202 PetscErrorCode  TSPreStep(TS ts)
2203 {
2204   PetscErrorCode ierr;
2205 
2206   PetscFunctionBegin;
2207   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2208   if (ts->prestep) {
2209     PetscStackCallStandard((*ts->prestep),(ts));
2210   }
2211   PetscFunctionReturn(0);
2212 }
2213 
2214 #undef __FUNCT__
2215 #define __FUNCT__ "TSSetPreStage"
2216 /*@C
2217   TSSetPreStage - Sets the general-purpose function
2218   called once at the beginning of each stage.
2219 
2220   Logically Collective on TS
2221 
2222   Input Parameters:
2223 + ts   - The TS context obtained from TSCreate()
2224 - func - The function
2225 
2226   Calling sequence of func:
2227 . PetscErrorCode func(TS ts, PetscReal stagetime);
2228 
2229   Level: intermediate
2230 
2231   Note:
2232   There may be several stages per time step. If the solve for a given stage fails, the step may be rejected and retried.
2233   The time step number being computed can be queried using TSGetTimeStepNumber() and the total size of the step being
2234   attempted can be obtained using TSGetTimeStep(). The time at the start of the step is available via TSGetTime().
2235 
2236 .keywords: TS, timestep
2237 .seealso: TSSetPostStage(), TSSetPreStep(), TSSetPostStep(), TSGetApplicationContext()
2238 @*/
2239 PetscErrorCode  TSSetPreStage(TS ts, PetscErrorCode (*func)(TS,PetscReal))
2240 {
2241   PetscFunctionBegin;
2242   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2243   ts->prestage = func;
2244   PetscFunctionReturn(0);
2245 }
2246 
2247 #undef __FUNCT__
2248 #define __FUNCT__ "TSSetPostStage"
2249 /*@C
2250   TSSetPostStage - Sets the general-purpose function
2251   called once at the end of each stage.
2252 
2253   Logically Collective on TS
2254 
2255   Input Parameters:
2256 + ts   - The TS context obtained from TSCreate()
2257 - func - The function
2258 
2259   Calling sequence of func:
2260 . PetscErrorCode func(TS ts, PetscReal stagetime, PetscInt stageindex, Vec* Y);
2261 
2262   Level: intermediate
2263 
2264   Note:
2265   There may be several stages per time step. If the solve for a given stage fails, the step may be rejected and retried.
2266   The time step number being computed can be queried using TSGetTimeStepNumber() and the total size of the step being
2267   attempted can be obtained using TSGetTimeStep(). The time at the start of the step is available via TSGetTime().
2268 
2269 .keywords: TS, timestep
2270 .seealso: TSSetPreStage(), TSSetPreStep(), TSSetPostStep(), TSGetApplicationContext()
2271 @*/
2272 PetscErrorCode  TSSetPostStage(TS ts, PetscErrorCode (*func)(TS,PetscReal,PetscInt,Vec*))
2273 {
2274   PetscFunctionBegin;
2275   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2276   ts->poststage = func;
2277   PetscFunctionReturn(0);
2278 }
2279 
2280 #undef __FUNCT__
2281 #define __FUNCT__ "TSPreStage"
2282 /*@
2283   TSPreStage - Runs the user-defined pre-stage function set using TSSetPreStage()
2284 
2285   Collective on TS
2286 
2287   Input Parameters:
2288 . ts          - The TS context obtained from TSCreate()
2289   stagetime   - The absolute time of the current stage
2290 
2291   Notes:
2292   TSPreStage() is typically used within time stepping implementations,
2293   most users would not generally call this routine themselves.
2294 
2295   Level: developer
2296 
2297 .keywords: TS, timestep
2298 .seealso: TSPostStage(), TSSetPreStep(), TSPreStep(), TSPostStep()
2299 @*/
2300 PetscErrorCode  TSPreStage(TS ts, PetscReal stagetime)
2301 {
2302   PetscErrorCode ierr;
2303 
2304   PetscFunctionBegin;
2305   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2306   if (ts->prestage) {
2307     PetscStackCallStandard((*ts->prestage),(ts,stagetime));
2308   }
2309   PetscFunctionReturn(0);
2310 }
2311 
2312 #undef __FUNCT__
2313 #define __FUNCT__ "TSPostStage"
2314 /*@
2315   TSPostStage - Runs the user-defined post-stage function set using TSSetPostStage()
2316 
2317   Collective on TS
2318 
2319   Input Parameters:
2320 . ts          - The TS context obtained from TSCreate()
2321   stagetime   - The absolute time of the current stage
2322   stageindex  - Stage number
2323   Y           - Array of vectors (of size = total number
2324                 of stages) with the stage solutions
2325 
2326   Notes:
2327   TSPostStage() is typically used within time stepping implementations,
2328   most users would not generally call this routine themselves.
2329 
2330   Level: developer
2331 
2332 .keywords: TS, timestep
2333 .seealso: TSPreStage(), TSSetPreStep(), TSPreStep(), TSPostStep()
2334 @*/
2335 PetscErrorCode  TSPostStage(TS ts, PetscReal stagetime, PetscInt stageindex, Vec *Y)
2336 {
2337   PetscErrorCode ierr;
2338 
2339   PetscFunctionBegin;
2340   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2341   if (ts->poststage) {
2342     PetscStackCallStandard((*ts->poststage),(ts,stagetime,stageindex,Y));
2343   }
2344   PetscFunctionReturn(0);
2345 }
2346 
2347 #undef __FUNCT__
2348 #define __FUNCT__ "TSSetPostStep"
2349 /*@C
2350   TSSetPostStep - Sets the general-purpose function
2351   called once at the end of each time step.
2352 
2353   Logically Collective on TS
2354 
2355   Input Parameters:
2356 + ts   - The TS context obtained from TSCreate()
2357 - func - The function
2358 
2359   Calling sequence of func:
2360 $ func (TS ts);
2361 
2362   Level: intermediate
2363 
2364 .keywords: TS, timestep
2365 .seealso: TSSetPreStep(), TSSetPreStage(), TSGetTimeStep(), TSGetTimeStepNumber(), TSGetTime()
2366 @*/
2367 PetscErrorCode  TSSetPostStep(TS ts, PetscErrorCode (*func)(TS))
2368 {
2369   PetscFunctionBegin;
2370   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2371   ts->poststep = func;
2372   PetscFunctionReturn(0);
2373 }
2374 
2375 #undef __FUNCT__
2376 #define __FUNCT__ "TSPostStep"
2377 /*@
2378   TSPostStep - Runs the user-defined post-step function.
2379 
2380   Collective on TS
2381 
2382   Input Parameters:
2383 . ts   - The TS context obtained from TSCreate()
2384 
2385   Notes:
2386   TSPostStep() is typically used within time stepping implementations,
2387   so most users would not generally call this routine themselves.
2388 
2389   Level: developer
2390 
2391 .keywords: TS, timestep
2392 @*/
2393 PetscErrorCode  TSPostStep(TS ts)
2394 {
2395   PetscErrorCode ierr;
2396 
2397   PetscFunctionBegin;
2398   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2399   if (ts->poststep) {
2400     PetscStackCallStandard((*ts->poststep),(ts));
2401   }
2402   PetscFunctionReturn(0);
2403 }
2404 
2405 /* ------------ Routines to set performance monitoring options ----------- */
2406 
2407 #undef __FUNCT__
2408 #define __FUNCT__ "TSMonitorSet"
2409 /*@C
2410    TSMonitorSet - Sets an ADDITIONAL function that is to be used at every
2411    timestep to display the iteration's  progress.
2412 
2413    Logically Collective on TS
2414 
2415    Input Parameters:
2416 +  ts - the TS context obtained from TSCreate()
2417 .  monitor - monitoring routine
2418 .  mctx - [optional] user-defined context for private data for the
2419              monitor routine (use NULL if no context is desired)
2420 -  monitordestroy - [optional] routine that frees monitor context
2421           (may be NULL)
2422 
2423    Calling sequence of monitor:
2424 $    int monitor(TS ts,PetscInt steps,PetscReal time,Vec u,void *mctx)
2425 
2426 +    ts - the TS context
2427 .    steps - iteration number (after the final time step the monitor routine is called with a step of -1, this is at the final time which may have
2428                                been interpolated to)
2429 .    time - current time
2430 .    u - current iterate
2431 -    mctx - [optional] monitoring context
2432 
2433    Notes:
2434    This routine adds an additional monitor to the list of monitors that
2435    already has been loaded.
2436 
2437    Fortran notes: Only a single monitor function can be set for each TS object
2438 
2439    Level: intermediate
2440 
2441 .keywords: TS, timestep, set, monitor
2442 
2443 .seealso: TSMonitorDefault(), TSMonitorCancel()
2444 @*/
2445 PetscErrorCode  TSMonitorSet(TS ts,PetscErrorCode (*monitor)(TS,PetscInt,PetscReal,Vec,void*),void *mctx,PetscErrorCode (*mdestroy)(void**))
2446 {
2447   PetscFunctionBegin;
2448   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2449   if (ts->numbermonitors >= MAXTSMONITORS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
2450   ts->monitor[ts->numbermonitors]          = monitor;
2451   ts->monitordestroy[ts->numbermonitors]   = mdestroy;
2452   ts->monitorcontext[ts->numbermonitors++] = (void*)mctx;
2453   PetscFunctionReturn(0);
2454 }
2455 
2456 #undef __FUNCT__
2457 #define __FUNCT__ "TSMonitorCancel"
2458 /*@C
2459    TSMonitorCancel - Clears all the monitors that have been set on a time-step object.
2460 
2461    Logically Collective on TS
2462 
2463    Input Parameters:
2464 .  ts - the TS context obtained from TSCreate()
2465 
2466    Notes:
2467    There is no way to remove a single, specific monitor.
2468 
2469    Level: intermediate
2470 
2471 .keywords: TS, timestep, set, monitor
2472 
2473 .seealso: TSMonitorDefault(), TSMonitorSet()
2474 @*/
2475 PetscErrorCode  TSMonitorCancel(TS ts)
2476 {
2477   PetscErrorCode ierr;
2478   PetscInt       i;
2479 
2480   PetscFunctionBegin;
2481   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2482   for (i=0; i<ts->numbermonitors; i++) {
2483     if (ts->monitordestroy[i]) {
2484       ierr = (*ts->monitordestroy[i])(&ts->monitorcontext[i]);CHKERRQ(ierr);
2485     }
2486   }
2487   ts->numbermonitors = 0;
2488   PetscFunctionReturn(0);
2489 }
2490 
2491 #undef __FUNCT__
2492 #define __FUNCT__ "TSMonitorDefault"
2493 /*@
2494    TSMonitorDefault - Sets the Default monitor
2495 
2496    Level: intermediate
2497 
2498 .keywords: TS, set, monitor
2499 
2500 .seealso: TSMonitorDefault(), TSMonitorSet()
2501 @*/
2502 PetscErrorCode TSMonitorDefault(TS ts,PetscInt step,PetscReal ptime,Vec v,void *dummy)
2503 {
2504   PetscErrorCode ierr;
2505   PetscViewer    viewer = dummy ? (PetscViewer) dummy : PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)ts));
2506 
2507   PetscFunctionBegin;
2508   ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)ts)->tablevel);CHKERRQ(ierr);
2509   ierr = PetscViewerASCIIPrintf(viewer,"%D TS dt %g time %g\n",step,(double)ts->time_step,(double)ptime);CHKERRQ(ierr);
2510   ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)ts)->tablevel);CHKERRQ(ierr);
2511   PetscFunctionReturn(0);
2512 }
2513 
2514 #undef __FUNCT__
2515 #define __FUNCT__ "TSSetRetainStages"
2516 /*@
2517    TSSetRetainStages - Request that all stages in the upcoming step be stored so that interpolation will be available.
2518 
2519    Logically Collective on TS
2520 
2521    Input Argument:
2522 .  ts - time stepping context
2523 
2524    Output Argument:
2525 .  flg - PETSC_TRUE or PETSC_FALSE
2526 
2527    Level: intermediate
2528 
2529 .keywords: TS, set
2530 
2531 .seealso: TSInterpolate(), TSSetPostStep()
2532 @*/
2533 PetscErrorCode TSSetRetainStages(TS ts,PetscBool flg)
2534 {
2535   PetscFunctionBegin;
2536   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2537   ts->retain_stages = flg;
2538   PetscFunctionReturn(0);
2539 }
2540 
2541 #undef __FUNCT__
2542 #define __FUNCT__ "TSInterpolate"
2543 /*@
2544    TSInterpolate - Interpolate the solution computed during the previous step to an arbitrary location in the interval
2545 
2546    Collective on TS
2547 
2548    Input Argument:
2549 +  ts - time stepping context
2550 -  t - time to interpolate to
2551 
2552    Output Argument:
2553 .  U - state at given time
2554 
2555    Notes:
2556    The user should call TSSetRetainStages() before taking a step in which interpolation will be requested.
2557 
2558    Level: intermediate
2559 
2560    Developer Notes:
2561    TSInterpolate() and the storing of previous steps/stages should be generalized to support delay differential equations and continuous adjoints.
2562 
2563 .keywords: TS, set
2564 
2565 .seealso: TSSetRetainStages(), TSSetPostStep()
2566 @*/
2567 PetscErrorCode TSInterpolate(TS ts,PetscReal t,Vec U)
2568 {
2569   PetscErrorCode ierr;
2570 
2571   PetscFunctionBegin;
2572   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2573   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
2574   if (t < ts->ptime - ts->time_step_prev || t > ts->ptime) SETERRQ3(PetscObjectComm((PetscObject)ts),PETSC_ERR_ARG_OUTOFRANGE,"Requested time %g not in last time steps [%g,%g]",t,(double)(ts->ptime-ts->time_step_prev),(double)ts->ptime);
2575   if (!ts->ops->interpolate) SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"%s does not provide interpolation",((PetscObject)ts)->type_name);
2576   ierr = (*ts->ops->interpolate)(ts,t,U);CHKERRQ(ierr);
2577   PetscFunctionReturn(0);
2578 }
2579 
2580 #undef __FUNCT__
2581 #define __FUNCT__ "TSStep"
2582 /*@
2583    TSStep - Steps one time step
2584 
2585    Collective on TS
2586 
2587    Input Parameter:
2588 .  ts - the TS context obtained from TSCreate()
2589 
2590    Level: intermediate
2591 
2592    Notes:
2593    The hook set using TSSetPreStep() is called before each attempt to take the step. In general, the time step size may
2594    be changed due to adaptive error controller or solve failures. Note that steps may contain multiple stages.
2595 
2596    This may over-step the final time provided in TSSetDuration() depending on the time-step used. TSSolve() interpolates to exactly the
2597    time provided in TSSetDuration(). One can use TSInterpolate() to determine an interpolated solution within the final timestep.
2598 
2599 .keywords: TS, timestep, solve
2600 
2601 .seealso: TSCreate(), TSSetUp(), TSDestroy(), TSSolve(), TSSetPreStep(), TSSetPreStage(), TSSetPostStage(), TSInterpolate()
2602 @*/
2603 PetscErrorCode  TSStep(TS ts)
2604 {
2605   DM               dm;
2606   PetscErrorCode   ierr;
2607   static PetscBool cite = PETSC_FALSE;
2608 
2609   PetscFunctionBegin;
2610   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2611   ierr = PetscCitationsRegister("@techreport{tspaper,\n"
2612                                 "  title       = {{PETSc/TS}: A Modern Scalable {DAE/ODE} Solver Library},\n"
2613                                 "  author      = {Shrirang Abhyankar and Jed Brown and Emil Constantinescu and Debojyoti Ghosh and Barry F. Smith},\n"
2614                                 "  type        = {Preprint},\n"
2615                                 "  number      = {ANL/MCS-P5061-0114},\n"
2616                                 "  institution = {Argonne National Laboratory},\n"
2617                                 "  year        = {2014}\n}\n",&cite);
2618 
2619   ierr = TSGetDM(ts, &dm);CHKERRQ(ierr);
2620   ierr = TSSetUp(ts);CHKERRQ(ierr);
2621 
2622   ts->reason = TS_CONVERGED_ITERATING;
2623   ts->ptime_prev = ts->ptime;
2624   ierr = DMSetOutputSequenceNumber(dm, ts->steps, ts->ptime);CHKERRQ(ierr);
2625   ierr = VecViewFromOptions(ts->vec_sol, ((PetscObject) ts)->prefix, "-ts_view_solution");CHKERRQ(ierr);
2626 
2627   if (!ts->ops->step) SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"TSStep not implemented for type '%s'",((PetscObject)ts)->type_name);
2628   ierr = PetscLogEventBegin(TS_Step,ts,0,0,0);CHKERRQ(ierr);
2629   ierr = (*ts->ops->step)(ts);CHKERRQ(ierr);
2630   ierr = PetscLogEventEnd(TS_Step,ts,0,0,0);CHKERRQ(ierr);
2631 
2632   ts->time_step_prev = ts->ptime - ts->ptime_prev;
2633   ierr = DMSetOutputSequenceNumber(dm, ts->steps, ts->ptime);CHKERRQ(ierr);
2634 
2635   if (ts->reason < 0) {
2636     if (ts->errorifstepfailed) {
2637       if (ts->reason == TS_DIVERGED_NONLINEAR_SOLVE) {
2638         SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_NOT_CONVERGED,"TSStep has failed due to %s, increase -ts_max_snes_failures or make negative to attempt recovery",TSConvergedReasons[ts->reason]);
2639       } else if (ts->reason == TS_DIVERGED_STEP_REJECTED) {
2640         SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_NOT_CONVERGED,"TSStep has failed due to %s, increase -ts_max_reject or make negative to attempt recovery",TSConvergedReasons[ts->reason]);
2641       } else SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_NOT_CONVERGED,"TSStep has failed due to %s",TSConvergedReasons[ts->reason]);
2642     }
2643   } else if (!ts->reason) {
2644     if (ts->steps >= ts->max_steps)     ts->reason = TS_CONVERGED_ITS;
2645     else if (ts->ptime >= ts->max_time) ts->reason = TS_CONVERGED_TIME;
2646   }
2647   PetscFunctionReturn(0);
2648 }
2649 
2650 #undef __FUNCT__
2651 #define __FUNCT__ "TSEvaluateStep"
2652 /*@
2653    TSEvaluateStep - Evaluate the solution at the end of a time step with a given order of accuracy.
2654 
2655    Collective on TS
2656 
2657    Input Arguments:
2658 +  ts - time stepping context
2659 .  order - desired order of accuracy
2660 -  done - whether the step was evaluated at this order (pass NULL to generate an error if not available)
2661 
2662    Output Arguments:
2663 .  U - state at the end of the current step
2664 
2665    Level: advanced
2666 
2667    Notes:
2668    This function cannot be called until all stages have been evaluated.
2669    It is normally called by adaptive controllers before a step has been accepted and may also be called by the user after TSStep() has returned.
2670 
2671 .seealso: TSStep(), TSAdapt
2672 @*/
2673 PetscErrorCode TSEvaluateStep(TS ts,PetscInt order,Vec U,PetscBool *done)
2674 {
2675   PetscErrorCode ierr;
2676 
2677   PetscFunctionBegin;
2678   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2679   PetscValidType(ts,1);
2680   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
2681   if (!ts->ops->evaluatestep) SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"TSEvaluateStep not implemented for type '%s'",((PetscObject)ts)->type_name);
2682   ierr = (*ts->ops->evaluatestep)(ts,order,U,done);CHKERRQ(ierr);
2683   PetscFunctionReturn(0);
2684 }
2685 
2686 #undef __FUNCT__
2687 #define __FUNCT__ "TSSolve"
2688 /*@
2689    TSSolve - Steps the requested number of timesteps.
2690 
2691    Collective on TS
2692 
2693    Input Parameter:
2694 +  ts - the TS context obtained from TSCreate()
2695 -  u - the solution vector  (can be null if TSSetSolution() was used, otherwise must contain the initial conditions)
2696 
2697    Level: beginner
2698 
2699    Notes:
2700    The final time returned by this function may be different from the time of the internally
2701    held state accessible by TSGetSolution() and TSGetTime() because the method may have
2702    stepped over the final time.
2703 
2704 .keywords: TS, timestep, solve
2705 
2706 .seealso: TSCreate(), TSSetSolution(), TSStep()
2707 @*/
2708 PetscErrorCode TSSolve(TS ts,Vec u)
2709 {
2710   Vec               solution;
2711   PetscErrorCode    ierr;
2712 
2713   PetscFunctionBegin;
2714   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2715   if (u) PetscValidHeaderSpecific(u,VEC_CLASSID,2);
2716   if (ts->exact_final_time == TS_EXACTFINALTIME_INTERPOLATE) {   /* Need ts->vec_sol to be distinct so it is not overwritten when we interpolate at the end */
2717     PetscValidHeaderSpecific(u,VEC_CLASSID,2);
2718     if (!ts->vec_sol || u == ts->vec_sol) {
2719       ierr = VecDuplicate(u,&solution);CHKERRQ(ierr);
2720       ierr = TSSetSolution(ts,solution);CHKERRQ(ierr);
2721       ierr = VecDestroy(&solution);CHKERRQ(ierr); /* grant ownership */
2722     }
2723     ierr = VecCopy(u,ts->vec_sol);CHKERRQ(ierr);
2724   } else if (u) {
2725     ierr = TSSetSolution(ts,u);CHKERRQ(ierr);
2726   }
2727   ierr = TSSetUp(ts);CHKERRQ(ierr);
2728   /* reset time step and iteration counters */
2729   ts->steps             = 0;
2730   ts->ksp_its           = 0;
2731   ts->snes_its          = 0;
2732   ts->num_snes_failures = 0;
2733   ts->reject            = 0;
2734   ts->reason            = TS_CONVERGED_ITERATING;
2735 
2736   ierr = TSViewFromOptions(ts,NULL,"-ts_view_pre");CHKERRQ(ierr);
2737 
2738   if (ts->ops->solve) {         /* This private interface is transitional and should be removed when all implementations are updated. */
2739     ierr = (*ts->ops->solve)(ts);CHKERRQ(ierr);
2740     ierr = VecCopy(ts->vec_sol,u);CHKERRQ(ierr);
2741     ts->solvetime = ts->ptime;
2742   } else {
2743     /* steps the requested number of timesteps. */
2744     if (ts->steps >= ts->max_steps)     ts->reason = TS_CONVERGED_ITS;
2745     else if (ts->ptime >= ts->max_time) ts->reason = TS_CONVERGED_TIME;
2746     while (!ts->reason) {
2747       ierr = TSMonitor(ts,ts->steps,ts->ptime,ts->vec_sol);CHKERRQ(ierr);
2748       ierr = TSStep(ts);CHKERRQ(ierr);
2749       if (ts->event) {
2750 	ierr = TSEventMonitor(ts);CHKERRQ(ierr);
2751 	if (ts->event->status != TSEVENT_PROCESSING) {
2752 	  ierr = TSPostStep(ts);CHKERRQ(ierr);
2753 	}
2754       } else {
2755 	ierr = TSPostStep(ts);CHKERRQ(ierr);
2756       }
2757     }
2758     if (ts->exact_final_time == TS_EXACTFINALTIME_INTERPOLATE && ts->ptime > ts->max_time) {
2759       ierr = TSInterpolate(ts,ts->max_time,u);CHKERRQ(ierr);
2760       ts->solvetime = ts->max_time;
2761       solution = u;
2762     } else {
2763       if (u) {ierr = VecCopy(ts->vec_sol,u);CHKERRQ(ierr);}
2764       ts->solvetime = ts->ptime;
2765       solution = ts->vec_sol;
2766     }
2767     ierr = TSMonitor(ts,ts->steps,ts->solvetime,solution);CHKERRQ(ierr);
2768     ierr = VecViewFromOptions(u, ((PetscObject) ts)->prefix, "-ts_view_solution");CHKERRQ(ierr);
2769   }
2770   ierr = TSViewFromOptions(ts,NULL,"-ts_view");CHKERRQ(ierr);
2771   ierr = PetscObjectSAWsBlock((PetscObject)ts);CHKERRQ(ierr);
2772   PetscFunctionReturn(0);
2773 }
2774 
2775 #undef __FUNCT__
2776 #define __FUNCT__ "TSMonitor"
2777 /*@
2778    TSMonitor - Runs all user-provided monitor routines set using TSMonitorSet()
2779 
2780    Collective on TS
2781 
2782    Input Parameters:
2783 +  ts - time stepping context obtained from TSCreate()
2784 .  step - step number that has just completed
2785 .  ptime - model time of the state
2786 -  u - state at the current model time
2787 
2788    Notes:
2789    TSMonitor() is typically used within the time stepping implementations.
2790    Users might call this function when using the TSStep() interface instead of TSSolve().
2791 
2792    Level: advanced
2793 
2794 .keywords: TS, timestep
2795 @*/
2796 PetscErrorCode TSMonitor(TS ts,PetscInt step,PetscReal ptime,Vec u)
2797 {
2798   PetscErrorCode ierr;
2799   PetscInt       i,n = ts->numbermonitors;
2800 
2801   PetscFunctionBegin;
2802   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2803   PetscValidHeaderSpecific(u,VEC_CLASSID,4);
2804   for (i=0; i<n; i++) {
2805     ierr = (*ts->monitor[i])(ts,step,ptime,u,ts->monitorcontext[i]);CHKERRQ(ierr);
2806   }
2807   PetscFunctionReturn(0);
2808 }
2809 
2810 /* ------------------------------------------------------------------------*/
2811 #undef __FUNCT__
2812 #define __FUNCT__ "TSMonitorLGCtxCreate"
2813 /*@C
2814    TSMonitorLGCtxCreate - Creates a line graph context for use with
2815    TS to monitor the solution process graphically in various ways
2816 
2817    Collective on TS
2818 
2819    Input Parameters:
2820 +  host - the X display to open, or null for the local machine
2821 .  label - the title to put in the title bar
2822 .  x, y - the screen coordinates of the upper left coordinate of the window
2823 .  m, n - the screen width and height in pixels
2824 -  howoften - if positive then determines the frequency of the plotting, if -1 then only at the final time
2825 
2826    Output Parameter:
2827 .  ctx - the context
2828 
2829    Options Database Key:
2830 +  -ts_monitor_lg_timestep - automatically sets line graph monitor
2831 .  -ts_monitor_lg_solution -
2832 .  -ts_monitor_lg_error -
2833 .  -ts_monitor_lg_ksp_iterations -
2834 .  -ts_monitor_lg_snes_iterations -
2835 -  -lg_indicate_data_points <true,false> - indicate the data points (at each time step) on the plot; default is true
2836 
2837    Notes:
2838    Use TSMonitorLGCtxDestroy() to destroy.
2839 
2840    Level: intermediate
2841 
2842 .keywords: TS, monitor, line graph, residual, seealso
2843 
2844 .seealso: TSMonitorLGTimeStep(), TSMonitorSet(), TSMonitorLGSolution(), TSMonitorLGError()
2845 
2846 @*/
2847 PetscErrorCode  TSMonitorLGCtxCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscInt howoften,TSMonitorLGCtx *ctx)
2848 {
2849   PetscDraw      win;
2850   PetscErrorCode ierr;
2851 
2852   PetscFunctionBegin;
2853   ierr = PetscNew(ctx);CHKERRQ(ierr);
2854   ierr = PetscDrawCreate(comm,host,label,x,y,m,n,&win);CHKERRQ(ierr);
2855   ierr = PetscDrawSetFromOptions(win);CHKERRQ(ierr);
2856   ierr = PetscDrawLGCreate(win,1,&(*ctx)->lg);CHKERRQ(ierr);
2857   ierr = PetscLogObjectParent((PetscObject)(*ctx)->lg,(PetscObject)win);CHKERRQ(ierr);
2858   ierr = PetscDrawLGIndicateDataPoints((*ctx)->lg,PETSC_TRUE);CHKERRQ(ierr);
2859   ierr = PetscDrawLGSetFromOptions((*ctx)->lg);CHKERRQ(ierr);
2860   (*ctx)->howoften = howoften;
2861   PetscFunctionReturn(0);
2862 }
2863 
2864 #undef __FUNCT__
2865 #define __FUNCT__ "TSMonitorLGTimeStep"
2866 PetscErrorCode TSMonitorLGTimeStep(TS ts,PetscInt step,PetscReal ptime,Vec v,void *monctx)
2867 {
2868   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
2869   PetscReal      x   = ptime,y;
2870   PetscErrorCode ierr;
2871 
2872   PetscFunctionBegin;
2873   if (!step) {
2874     PetscDrawAxis axis;
2875     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
2876     ierr = PetscDrawAxisSetLabels(axis,"Timestep as function of time","Time","Time step");CHKERRQ(ierr);
2877     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
2878     ierr = PetscDrawLGIndicateDataPoints(ctx->lg,PETSC_TRUE);CHKERRQ(ierr);
2879   }
2880   ierr = TSGetTimeStep(ts,&y);CHKERRQ(ierr);
2881   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
2882   if (((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason)) {
2883     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
2884   }
2885   PetscFunctionReturn(0);
2886 }
2887 
2888 #undef __FUNCT__
2889 #define __FUNCT__ "TSMonitorLGCtxDestroy"
2890 /*@C
2891    TSMonitorLGCtxDestroy - Destroys a line graph context that was created
2892    with TSMonitorLGCtxCreate().
2893 
2894    Collective on TSMonitorLGCtx
2895 
2896    Input Parameter:
2897 .  ctx - the monitor context
2898 
2899    Level: intermediate
2900 
2901 .keywords: TS, monitor, line graph, destroy
2902 
2903 .seealso: TSMonitorLGCtxCreate(),  TSMonitorSet(), TSMonitorLGTimeStep();
2904 @*/
2905 PetscErrorCode  TSMonitorLGCtxDestroy(TSMonitorLGCtx *ctx)
2906 {
2907   PetscDraw      draw;
2908   PetscErrorCode ierr;
2909 
2910   PetscFunctionBegin;
2911   ierr = PetscDrawLGGetDraw((*ctx)->lg,&draw);CHKERRQ(ierr);
2912   ierr = PetscDrawDestroy(&draw);CHKERRQ(ierr);
2913   ierr = PetscDrawLGDestroy(&(*ctx)->lg);CHKERRQ(ierr);
2914   ierr = PetscFree(*ctx);CHKERRQ(ierr);
2915   PetscFunctionReturn(0);
2916 }
2917 
2918 #undef __FUNCT__
2919 #define __FUNCT__ "TSGetTime"
2920 /*@
2921    TSGetTime - Gets the time of the most recently completed step.
2922 
2923    Not Collective
2924 
2925    Input Parameter:
2926 .  ts - the TS context obtained from TSCreate()
2927 
2928    Output Parameter:
2929 .  t  - the current time
2930 
2931    Level: beginner
2932 
2933    Note:
2934    When called during time step evaluation (e.g. during residual evaluation or via hooks set using TSSetPreStep(),
2935    TSSetPreStage(), TSSetPostStage(), or TSSetPostStep()), the time is the time at the start of the step being evaluated.
2936 
2937 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
2938 
2939 .keywords: TS, get, time
2940 @*/
2941 PetscErrorCode  TSGetTime(TS ts,PetscReal *t)
2942 {
2943   PetscFunctionBegin;
2944   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2945   PetscValidRealPointer(t,2);
2946   *t = ts->ptime;
2947   PetscFunctionReturn(0);
2948 }
2949 
2950 #undef __FUNCT__
2951 #define __FUNCT__ "TSSetTime"
2952 /*@
2953    TSSetTime - Allows one to reset the time.
2954 
2955    Logically Collective on TS
2956 
2957    Input Parameters:
2958 +  ts - the TS context obtained from TSCreate()
2959 -  time - the time
2960 
2961    Level: intermediate
2962 
2963 .seealso: TSGetTime(), TSSetDuration()
2964 
2965 .keywords: TS, set, time
2966 @*/
2967 PetscErrorCode  TSSetTime(TS ts, PetscReal t)
2968 {
2969   PetscFunctionBegin;
2970   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2971   PetscValidLogicalCollectiveReal(ts,t,2);
2972   ts->ptime = t;
2973   PetscFunctionReturn(0);
2974 }
2975 
2976 #undef __FUNCT__
2977 #define __FUNCT__ "TSSetOptionsPrefix"
2978 /*@C
2979    TSSetOptionsPrefix - Sets the prefix used for searching for all
2980    TS options in the database.
2981 
2982    Logically Collective on TS
2983 
2984    Input Parameter:
2985 +  ts     - The TS context
2986 -  prefix - The prefix to prepend to all option names
2987 
2988    Notes:
2989    A hyphen (-) must NOT be given at the beginning of the prefix name.
2990    The first character of all runtime options is AUTOMATICALLY the
2991    hyphen.
2992 
2993    Level: advanced
2994 
2995 .keywords: TS, set, options, prefix, database
2996 
2997 .seealso: TSSetFromOptions()
2998 
2999 @*/
3000 PetscErrorCode  TSSetOptionsPrefix(TS ts,const char prefix[])
3001 {
3002   PetscErrorCode ierr;
3003   SNES           snes;
3004 
3005   PetscFunctionBegin;
3006   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3007   ierr = PetscObjectSetOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
3008   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3009   ierr = SNESSetOptionsPrefix(snes,prefix);CHKERRQ(ierr);
3010   PetscFunctionReturn(0);
3011 }
3012 
3013 
3014 #undef __FUNCT__
3015 #define __FUNCT__ "TSAppendOptionsPrefix"
3016 /*@C
3017    TSAppendOptionsPrefix - Appends to the prefix used for searching for all
3018    TS options in the database.
3019 
3020    Logically Collective on TS
3021 
3022    Input Parameter:
3023 +  ts     - The TS context
3024 -  prefix - The prefix to prepend to all option names
3025 
3026    Notes:
3027    A hyphen (-) must NOT be given at the beginning of the prefix name.
3028    The first character of all runtime options is AUTOMATICALLY the
3029    hyphen.
3030 
3031    Level: advanced
3032 
3033 .keywords: TS, append, options, prefix, database
3034 
3035 .seealso: TSGetOptionsPrefix()
3036 
3037 @*/
3038 PetscErrorCode  TSAppendOptionsPrefix(TS ts,const char prefix[])
3039 {
3040   PetscErrorCode ierr;
3041   SNES           snes;
3042 
3043   PetscFunctionBegin;
3044   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3045   ierr = PetscObjectAppendOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
3046   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3047   ierr = SNESAppendOptionsPrefix(snes,prefix);CHKERRQ(ierr);
3048   PetscFunctionReturn(0);
3049 }
3050 
3051 #undef __FUNCT__
3052 #define __FUNCT__ "TSGetOptionsPrefix"
3053 /*@C
3054    TSGetOptionsPrefix - Sets the prefix used for searching for all
3055    TS options in the database.
3056 
3057    Not Collective
3058 
3059    Input Parameter:
3060 .  ts - The TS context
3061 
3062    Output Parameter:
3063 .  prefix - A pointer to the prefix string used
3064 
3065    Notes: On the fortran side, the user should pass in a string 'prifix' of
3066    sufficient length to hold the prefix.
3067 
3068    Level: intermediate
3069 
3070 .keywords: TS, get, options, prefix, database
3071 
3072 .seealso: TSAppendOptionsPrefix()
3073 @*/
3074 PetscErrorCode  TSGetOptionsPrefix(TS ts,const char *prefix[])
3075 {
3076   PetscErrorCode ierr;
3077 
3078   PetscFunctionBegin;
3079   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3080   PetscValidPointer(prefix,2);
3081   ierr = PetscObjectGetOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
3082   PetscFunctionReturn(0);
3083 }
3084 
3085 #undef __FUNCT__
3086 #define __FUNCT__ "TSGetRHSJacobian"
3087 /*@C
3088    TSGetRHSJacobian - Returns the Jacobian J at the present timestep.
3089 
3090    Not Collective, but parallel objects are returned if TS is parallel
3091 
3092    Input Parameter:
3093 .  ts  - The TS context obtained from TSCreate()
3094 
3095    Output Parameters:
3096 +  Amat - The (approximate) Jacobian J of G, where U_t = G(U,t)  (or NULL)
3097 .  Pmat - The matrix from which the preconditioner is constructed, usually the same as Amat  (or NULL)
3098 .  func - Function to compute the Jacobian of the RHS  (or NULL)
3099 -  ctx - User-defined context for Jacobian evaluation routine  (or NULL)
3100 
3101    Notes: You can pass in NULL for any return argument you do not need.
3102 
3103    Level: intermediate
3104 
3105 .seealso: TSGetTimeStep(), TSGetMatrices(), TSGetTime(), TSGetTimeStepNumber()
3106 
3107 .keywords: TS, timestep, get, matrix, Jacobian
3108 @*/
3109 PetscErrorCode  TSGetRHSJacobian(TS ts,Mat *Amat,Mat *Pmat,TSRHSJacobian *func,void **ctx)
3110 {
3111   PetscErrorCode ierr;
3112   SNES           snes;
3113   DM             dm;
3114 
3115   PetscFunctionBegin;
3116   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3117   ierr = SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);CHKERRQ(ierr);
3118   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
3119   ierr = DMTSGetRHSJacobian(dm,func,ctx);CHKERRQ(ierr);
3120   PetscFunctionReturn(0);
3121 }
3122 
3123 #undef __FUNCT__
3124 #define __FUNCT__ "TSGetIJacobian"
3125 /*@C
3126    TSGetIJacobian - Returns the implicit Jacobian at the present timestep.
3127 
3128    Not Collective, but parallel objects are returned if TS is parallel
3129 
3130    Input Parameter:
3131 .  ts  - The TS context obtained from TSCreate()
3132 
3133    Output Parameters:
3134 +  Amat  - The (approximate) Jacobian of F(t,U,U_t)
3135 .  Pmat - The matrix from which the preconditioner is constructed, often the same as Amat
3136 .  f   - The function to compute the matrices
3137 - ctx - User-defined context for Jacobian evaluation routine
3138 
3139    Notes: You can pass in NULL for any return argument you do not need.
3140 
3141    Level: advanced
3142 
3143 .seealso: TSGetTimeStep(), TSGetRHSJacobian(), TSGetMatrices(), TSGetTime(), TSGetTimeStepNumber()
3144 
3145 .keywords: TS, timestep, get, matrix, Jacobian
3146 @*/
3147 PetscErrorCode  TSGetIJacobian(TS ts,Mat *Amat,Mat *Pmat,TSIJacobian *f,void **ctx)
3148 {
3149   PetscErrorCode ierr;
3150   SNES           snes;
3151   DM             dm;
3152 
3153   PetscFunctionBegin;
3154   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3155   ierr = SNESSetUpMatrices(snes);CHKERRQ(ierr);
3156   ierr = SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);CHKERRQ(ierr);
3157   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
3158   ierr = DMTSGetIJacobian(dm,f,ctx);CHKERRQ(ierr);
3159   PetscFunctionReturn(0);
3160 }
3161 
3162 
3163 #undef __FUNCT__
3164 #define __FUNCT__ "TSMonitorDrawSolution"
3165 /*@C
3166    TSMonitorDrawSolution - Monitors progress of the TS solvers by calling
3167    VecView() for the solution at each timestep
3168 
3169    Collective on TS
3170 
3171    Input Parameters:
3172 +  ts - the TS context
3173 .  step - current time-step
3174 .  ptime - current time
3175 -  dummy - either a viewer or NULL
3176 
3177    Options Database:
3178 .   -ts_monitor_draw_solution_initial - show initial solution as well as current solution
3179 
3180    Notes: the initial solution and current solution are not displayed with a common axis scaling so generally the option -ts_monitor_draw_solution_initial
3181        will look bad
3182 
3183    Level: intermediate
3184 
3185 .keywords: TS,  vector, monitor, view
3186 
3187 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3188 @*/
3189 PetscErrorCode  TSMonitorDrawSolution(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
3190 {
3191   PetscErrorCode   ierr;
3192   TSMonitorDrawCtx ictx = (TSMonitorDrawCtx)dummy;
3193   PetscDraw        draw;
3194 
3195   PetscFunctionBegin;
3196   if (!step && ictx->showinitial) {
3197     if (!ictx->initialsolution) {
3198       ierr = VecDuplicate(u,&ictx->initialsolution);CHKERRQ(ierr);
3199     }
3200     ierr = VecCopy(u,ictx->initialsolution);CHKERRQ(ierr);
3201   }
3202   if (!(((ictx->howoften > 0) && (!(step % ictx->howoften))) || ((ictx->howoften == -1) && ts->reason))) PetscFunctionReturn(0);
3203 
3204   if (ictx->showinitial) {
3205     PetscReal pause;
3206     ierr = PetscViewerDrawGetPause(ictx->viewer,&pause);CHKERRQ(ierr);
3207     ierr = PetscViewerDrawSetPause(ictx->viewer,0.0);CHKERRQ(ierr);
3208     ierr = VecView(ictx->initialsolution,ictx->viewer);CHKERRQ(ierr);
3209     ierr = PetscViewerDrawSetPause(ictx->viewer,pause);CHKERRQ(ierr);
3210     ierr = PetscViewerDrawSetHold(ictx->viewer,PETSC_TRUE);CHKERRQ(ierr);
3211   }
3212   ierr = VecView(u,ictx->viewer);CHKERRQ(ierr);
3213   if (ictx->showtimestepandtime) {
3214     PetscReal xl,yl,xr,yr,tw,w,h;
3215     char      time[32];
3216     size_t    len;
3217 
3218     ierr = PetscViewerDrawGetDraw(ictx->viewer,0,&draw);CHKERRQ(ierr);
3219     ierr = PetscSNPrintf(time,32,"Timestep %d Time %f",(int)step,(double)ptime);CHKERRQ(ierr);
3220     ierr = PetscDrawGetCoordinates(draw,&xl,&yl,&xr,&yr);CHKERRQ(ierr);
3221     ierr =  PetscStrlen(time,&len);CHKERRQ(ierr);
3222     ierr = PetscDrawStringGetSize(draw,&tw,NULL);CHKERRQ(ierr);
3223     w    = xl + .5*(xr - xl) - .5*len*tw;
3224     h    = yl + .95*(yr - yl);
3225     ierr = PetscDrawString(draw,w,h,PETSC_DRAW_BLACK,time);CHKERRQ(ierr);
3226     ierr = PetscDrawFlush(draw);CHKERRQ(ierr);
3227   }
3228 
3229   if (ictx->showinitial) {
3230     ierr = PetscViewerDrawSetHold(ictx->viewer,PETSC_FALSE);CHKERRQ(ierr);
3231   }
3232   PetscFunctionReturn(0);
3233 }
3234 
3235 #undef __FUNCT__
3236 #define __FUNCT__ "TSMonitorDrawSolutionPhase"
3237 /*@C
3238    TSMonitorDrawSolutionPhase - Monitors progress of the TS solvers by plotting the solution as a phase diagram
3239 
3240    Collective on TS
3241 
3242    Input Parameters:
3243 +  ts - the TS context
3244 .  step - current time-step
3245 .  ptime - current time
3246 -  dummy - either a viewer or NULL
3247 
3248    Level: intermediate
3249 
3250 .keywords: TS,  vector, monitor, view
3251 
3252 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3253 @*/
3254 PetscErrorCode  TSMonitorDrawSolutionPhase(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
3255 {
3256   PetscErrorCode    ierr;
3257   TSMonitorDrawCtx  ictx = (TSMonitorDrawCtx)dummy;
3258   PetscDraw         draw;
3259   MPI_Comm          comm;
3260   PetscInt          n;
3261   PetscMPIInt       size;
3262   PetscReal         xl,yl,xr,yr,tw,w,h;
3263   char              time[32];
3264   size_t            len;
3265   const PetscScalar *U;
3266 
3267   PetscFunctionBegin;
3268   ierr = PetscObjectGetComm((PetscObject)ts,&comm);CHKERRQ(ierr);
3269   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
3270   if (size != 1) SETERRQ(comm,PETSC_ERR_SUP,"Only allowed for sequential runs");
3271   ierr = VecGetSize(u,&n);CHKERRQ(ierr);
3272   if (n != 2) SETERRQ(comm,PETSC_ERR_SUP,"Only for ODEs with two unknowns");
3273 
3274   ierr = PetscViewerDrawGetDraw(ictx->viewer,0,&draw);CHKERRQ(ierr);
3275 
3276   ierr = VecGetArrayRead(u,&U);CHKERRQ(ierr);
3277   ierr = PetscDrawAxisGetLimits(ictx->axis,&xl,&xr,&yl,&yr);CHKERRQ(ierr);
3278   if ((PetscRealPart(U[0]) < xl) || (PetscRealPart(U[1]) < yl) || (PetscRealPart(U[0]) > xr) || (PetscRealPart(U[1]) > yr)) {
3279       ierr = VecRestoreArrayRead(u,&U);CHKERRQ(ierr);
3280       PetscFunctionReturn(0);
3281   }
3282   if (!step) ictx->color++;
3283   ierr = PetscDrawPoint(draw,PetscRealPart(U[0]),PetscRealPart(U[1]),ictx->color);CHKERRQ(ierr);
3284   ierr = VecRestoreArrayRead(u,&U);CHKERRQ(ierr);
3285 
3286   if (ictx->showtimestepandtime) {
3287     ierr = PetscDrawGetCoordinates(draw,&xl,&yl,&xr,&yr);CHKERRQ(ierr);
3288     ierr = PetscSNPrintf(time,32,"Timestep %d Time %f",(int)step,(double)ptime);CHKERRQ(ierr);
3289     ierr = PetscStrlen(time,&len);CHKERRQ(ierr);
3290     ierr = PetscDrawStringGetSize(draw,&tw,NULL);CHKERRQ(ierr);
3291     w    = xl + .5*(xr - xl) - .5*len*tw;
3292     h    = yl + .95*(yr - yl);
3293     ierr = PetscDrawString(draw,w,h,PETSC_DRAW_BLACK,time);CHKERRQ(ierr);
3294   }
3295   ierr = PetscDrawFlush(draw);CHKERRQ(ierr);
3296   PetscFunctionReturn(0);
3297 }
3298 
3299 
3300 #undef __FUNCT__
3301 #define __FUNCT__ "TSMonitorDrawCtxDestroy"
3302 /*@C
3303    TSMonitorDrawCtxDestroy - Destroys the monitor context for TSMonitorDrawSolution()
3304 
3305    Collective on TS
3306 
3307    Input Parameters:
3308 .    ctx - the monitor context
3309 
3310    Level: intermediate
3311 
3312 .keywords: TS,  vector, monitor, view
3313 
3314 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSMonitorDrawSolution(), TSMonitorDrawError()
3315 @*/
3316 PetscErrorCode  TSMonitorDrawCtxDestroy(TSMonitorDrawCtx *ictx)
3317 {
3318   PetscErrorCode ierr;
3319 
3320   PetscFunctionBegin;
3321   ierr = PetscDrawAxisDestroy(&(*ictx)->axis);CHKERRQ(ierr);
3322   ierr = PetscViewerDestroy(&(*ictx)->viewer);CHKERRQ(ierr);
3323   ierr = VecDestroy(&(*ictx)->initialsolution);CHKERRQ(ierr);
3324   ierr = PetscFree(*ictx);CHKERRQ(ierr);
3325   PetscFunctionReturn(0);
3326 }
3327 
3328 #undef __FUNCT__
3329 #define __FUNCT__ "TSMonitorDrawCtxCreate"
3330 /*@C
3331    TSMonitorDrawCtxCreate - Creates the monitor context for TSMonitorDrawCtx
3332 
3333    Collective on TS
3334 
3335    Input Parameter:
3336 .    ts - time-step context
3337 
3338    Output Patameter:
3339 .    ctx - the monitor context
3340 
3341    Options Database:
3342 .   -ts_monitor_draw_solution_initial - show initial solution as well as current solution
3343 
3344    Level: intermediate
3345 
3346 .keywords: TS,  vector, monitor, view
3347 
3348 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSMonitorDrawCtx()
3349 @*/
3350 PetscErrorCode  TSMonitorDrawCtxCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscInt howoften,TSMonitorDrawCtx *ctx)
3351 {
3352   PetscErrorCode   ierr;
3353 
3354   PetscFunctionBegin;
3355   ierr = PetscNew(ctx);CHKERRQ(ierr);
3356   ierr = PetscViewerDrawOpen(comm,host,label,x,y,m,n,&(*ctx)->viewer);CHKERRQ(ierr);
3357   ierr = PetscViewerSetFromOptions((*ctx)->viewer);CHKERRQ(ierr);
3358 
3359   (*ctx)->howoften    = howoften;
3360   (*ctx)->showinitial = PETSC_FALSE;
3361   ierr = PetscOptionsGetBool(NULL,"-ts_monitor_draw_solution_initial",&(*ctx)->showinitial,NULL);CHKERRQ(ierr);
3362 
3363   (*ctx)->showtimestepandtime = PETSC_FALSE;
3364   ierr = PetscOptionsGetBool(NULL,"-ts_monitor_draw_solution_show_time",&(*ctx)->showtimestepandtime,NULL);CHKERRQ(ierr);
3365   (*ctx)->color = PETSC_DRAW_WHITE;
3366   PetscFunctionReturn(0);
3367 }
3368 
3369 #undef __FUNCT__
3370 #define __FUNCT__ "TSMonitorDrawError"
3371 /*@C
3372    TSMonitorDrawError - Monitors progress of the TS solvers by calling
3373    VecView() for the error at each timestep
3374 
3375    Collective on TS
3376 
3377    Input Parameters:
3378 +  ts - the TS context
3379 .  step - current time-step
3380 .  ptime - current time
3381 -  dummy - either a viewer or NULL
3382 
3383    Level: intermediate
3384 
3385 .keywords: TS,  vector, monitor, view
3386 
3387 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3388 @*/
3389 PetscErrorCode  TSMonitorDrawError(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
3390 {
3391   PetscErrorCode   ierr;
3392   TSMonitorDrawCtx ctx    = (TSMonitorDrawCtx)dummy;
3393   PetscViewer      viewer = ctx->viewer;
3394   Vec              work;
3395 
3396   PetscFunctionBegin;
3397   if (!(((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason))) PetscFunctionReturn(0);
3398   ierr = VecDuplicate(u,&work);CHKERRQ(ierr);
3399   ierr = TSComputeSolutionFunction(ts,ptime,work);CHKERRQ(ierr);
3400   ierr = VecAXPY(work,-1.0,u);CHKERRQ(ierr);
3401   ierr = VecView(work,viewer);CHKERRQ(ierr);
3402   ierr = VecDestroy(&work);CHKERRQ(ierr);
3403   PetscFunctionReturn(0);
3404 }
3405 
3406 #include <petsc-private/dmimpl.h>
3407 #undef __FUNCT__
3408 #define __FUNCT__ "TSSetDM"
3409 /*@
3410    TSSetDM - Sets the DM that may be used by some preconditioners
3411 
3412    Logically Collective on TS and DM
3413 
3414    Input Parameters:
3415 +  ts - the preconditioner context
3416 -  dm - the dm
3417 
3418    Level: intermediate
3419 
3420 
3421 .seealso: TSGetDM(), SNESSetDM(), SNESGetDM()
3422 @*/
3423 PetscErrorCode  TSSetDM(TS ts,DM dm)
3424 {
3425   PetscErrorCode ierr;
3426   SNES           snes;
3427   DMTS           tsdm;
3428 
3429   PetscFunctionBegin;
3430   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3431   ierr = PetscObjectReference((PetscObject)dm);CHKERRQ(ierr);
3432   if (ts->dm) {               /* Move the DMTS context over to the new DM unless the new DM already has one */
3433     if (ts->dm->dmts && !dm->dmts) {
3434       ierr = DMCopyDMTS(ts->dm,dm);CHKERRQ(ierr);
3435       ierr = DMGetDMTS(ts->dm,&tsdm);CHKERRQ(ierr);
3436       if (tsdm->originaldm == ts->dm) { /* Grant write privileges to the replacement DM */
3437         tsdm->originaldm = dm;
3438       }
3439     }
3440     ierr = DMDestroy(&ts->dm);CHKERRQ(ierr);
3441   }
3442   ts->dm = dm;
3443 
3444   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3445   ierr = SNESSetDM(snes,dm);CHKERRQ(ierr);
3446   PetscFunctionReturn(0);
3447 }
3448 
3449 #undef __FUNCT__
3450 #define __FUNCT__ "TSGetDM"
3451 /*@
3452    TSGetDM - Gets the DM that may be used by some preconditioners
3453 
3454    Not Collective
3455 
3456    Input Parameter:
3457 . ts - the preconditioner context
3458 
3459    Output Parameter:
3460 .  dm - the dm
3461 
3462    Level: intermediate
3463 
3464 
3465 .seealso: TSSetDM(), SNESSetDM(), SNESGetDM()
3466 @*/
3467 PetscErrorCode  TSGetDM(TS ts,DM *dm)
3468 {
3469   PetscErrorCode ierr;
3470 
3471   PetscFunctionBegin;
3472   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3473   if (!ts->dm) {
3474     ierr = DMShellCreate(PetscObjectComm((PetscObject)ts),&ts->dm);CHKERRQ(ierr);
3475     if (ts->snes) {ierr = SNESSetDM(ts->snes,ts->dm);CHKERRQ(ierr);}
3476   }
3477   *dm = ts->dm;
3478   PetscFunctionReturn(0);
3479 }
3480 
3481 #undef __FUNCT__
3482 #define __FUNCT__ "SNESTSFormFunction"
3483 /*@
3484    SNESTSFormFunction - Function to evaluate nonlinear residual
3485 
3486    Logically Collective on SNES
3487 
3488    Input Parameter:
3489 + snes - nonlinear solver
3490 . U - the current state at which to evaluate the residual
3491 - ctx - user context, must be a TS
3492 
3493    Output Parameter:
3494 . F - the nonlinear residual
3495 
3496    Notes:
3497    This function is not normally called by users and is automatically registered with the SNES used by TS.
3498    It is most frequently passed to MatFDColoringSetFunction().
3499 
3500    Level: advanced
3501 
3502 .seealso: SNESSetFunction(), MatFDColoringSetFunction()
3503 @*/
3504 PetscErrorCode  SNESTSFormFunction(SNES snes,Vec U,Vec F,void *ctx)
3505 {
3506   TS             ts = (TS)ctx;
3507   PetscErrorCode ierr;
3508 
3509   PetscFunctionBegin;
3510   PetscValidHeaderSpecific(snes,SNES_CLASSID,1);
3511   PetscValidHeaderSpecific(U,VEC_CLASSID,2);
3512   PetscValidHeaderSpecific(F,VEC_CLASSID,3);
3513   PetscValidHeaderSpecific(ts,TS_CLASSID,4);
3514   ierr = (ts->ops->snesfunction)(snes,U,F,ts);CHKERRQ(ierr);
3515   PetscFunctionReturn(0);
3516 }
3517 
3518 #undef __FUNCT__
3519 #define __FUNCT__ "SNESTSFormJacobian"
3520 /*@
3521    SNESTSFormJacobian - Function to evaluate the Jacobian
3522 
3523    Collective on SNES
3524 
3525    Input Parameter:
3526 + snes - nonlinear solver
3527 . U - the current state at which to evaluate the residual
3528 - ctx - user context, must be a TS
3529 
3530    Output Parameter:
3531 + A - the Jacobian
3532 . B - the preconditioning matrix (may be the same as A)
3533 - flag - indicates any structure change in the matrix
3534 
3535    Notes:
3536    This function is not normally called by users and is automatically registered with the SNES used by TS.
3537 
3538    Level: developer
3539 
3540 .seealso: SNESSetJacobian()
3541 @*/
3542 PetscErrorCode  SNESTSFormJacobian(SNES snes,Vec U,Mat A,Mat B,void *ctx)
3543 {
3544   TS             ts = (TS)ctx;
3545   PetscErrorCode ierr;
3546 
3547   PetscFunctionBegin;
3548   PetscValidHeaderSpecific(snes,SNES_CLASSID,1);
3549   PetscValidHeaderSpecific(U,VEC_CLASSID,2);
3550   PetscValidPointer(A,3);
3551   PetscValidHeaderSpecific(A,MAT_CLASSID,3);
3552   PetscValidPointer(B,4);
3553   PetscValidHeaderSpecific(B,MAT_CLASSID,4);
3554   PetscValidHeaderSpecific(ts,TS_CLASSID,6);
3555   ierr = (ts->ops->snesjacobian)(snes,U,A,B,ts);CHKERRQ(ierr);
3556   PetscFunctionReturn(0);
3557 }
3558 
3559 #undef __FUNCT__
3560 #define __FUNCT__ "TSComputeRHSFunctionLinear"
3561 /*@C
3562    TSComputeRHSFunctionLinear - Evaluate the right hand side via the user-provided Jacobian, for linear problems only
3563 
3564    Collective on TS
3565 
3566    Input Arguments:
3567 +  ts - time stepping context
3568 .  t - time at which to evaluate
3569 .  U - state at which to evaluate
3570 -  ctx - context
3571 
3572    Output Arguments:
3573 .  F - right hand side
3574 
3575    Level: intermediate
3576 
3577    Notes:
3578    This function is intended to be passed to TSSetRHSFunction() to evaluate the right hand side for linear problems.
3579    The matrix (and optionally the evaluation context) should be passed to TSSetRHSJacobian().
3580 
3581 .seealso: TSSetRHSFunction(), TSSetRHSJacobian(), TSComputeRHSJacobianConstant()
3582 @*/
3583 PetscErrorCode TSComputeRHSFunctionLinear(TS ts,PetscReal t,Vec U,Vec F,void *ctx)
3584 {
3585   PetscErrorCode ierr;
3586   Mat            Arhs,Brhs;
3587 
3588   PetscFunctionBegin;
3589   ierr = TSGetRHSMats_Private(ts,&Arhs,&Brhs);CHKERRQ(ierr);
3590   ierr = TSComputeRHSJacobian(ts,t,U,Arhs,Brhs);CHKERRQ(ierr);
3591   ierr = MatMult(Arhs,U,F);CHKERRQ(ierr);
3592   PetscFunctionReturn(0);
3593 }
3594 
3595 #undef __FUNCT__
3596 #define __FUNCT__ "TSComputeRHSJacobianConstant"
3597 /*@C
3598    TSComputeRHSJacobianConstant - Reuses a Jacobian that is time-independent.
3599 
3600    Collective on TS
3601 
3602    Input Arguments:
3603 +  ts - time stepping context
3604 .  t - time at which to evaluate
3605 .  U - state at which to evaluate
3606 -  ctx - context
3607 
3608    Output Arguments:
3609 +  A - pointer to operator
3610 .  B - pointer to preconditioning matrix
3611 -  flg - matrix structure flag
3612 
3613    Level: intermediate
3614 
3615    Notes:
3616    This function is intended to be passed to TSSetRHSJacobian() to evaluate the Jacobian for linear time-independent problems.
3617 
3618 .seealso: TSSetRHSFunction(), TSSetRHSJacobian(), TSComputeRHSFunctionLinear()
3619 @*/
3620 PetscErrorCode TSComputeRHSJacobianConstant(TS ts,PetscReal t,Vec U,Mat A,Mat B,void *ctx)
3621 {
3622   PetscFunctionBegin;
3623   PetscFunctionReturn(0);
3624 }
3625 
3626 #undef __FUNCT__
3627 #define __FUNCT__ "TSComputeIFunctionLinear"
3628 /*@C
3629    TSComputeIFunctionLinear - Evaluate the left hand side via the user-provided Jacobian, for linear problems only
3630 
3631    Collective on TS
3632 
3633    Input Arguments:
3634 +  ts - time stepping context
3635 .  t - time at which to evaluate
3636 .  U - state at which to evaluate
3637 .  Udot - time derivative of state vector
3638 -  ctx - context
3639 
3640    Output Arguments:
3641 .  F - left hand side
3642 
3643    Level: intermediate
3644 
3645    Notes:
3646    The assumption here is that the left hand side is of the form A*Udot (and not A*Udot + B*U). For other cases, the
3647    user is required to write their own TSComputeIFunction.
3648    This function is intended to be passed to TSSetIFunction() to evaluate the left hand side for linear problems.
3649    The matrix (and optionally the evaluation context) should be passed to TSSetIJacobian().
3650 
3651 .seealso: TSSetIFunction(), TSSetIJacobian(), TSComputeIJacobianConstant()
3652 @*/
3653 PetscErrorCode TSComputeIFunctionLinear(TS ts,PetscReal t,Vec U,Vec Udot,Vec F,void *ctx)
3654 {
3655   PetscErrorCode ierr;
3656   Mat            A,B;
3657 
3658   PetscFunctionBegin;
3659   ierr = TSGetIJacobian(ts,&A,&B,NULL,NULL);CHKERRQ(ierr);
3660   ierr = TSComputeIJacobian(ts,t,U,Udot,1.0,A,B,PETSC_TRUE);CHKERRQ(ierr);
3661   ierr = MatMult(A,Udot,F);CHKERRQ(ierr);
3662   PetscFunctionReturn(0);
3663 }
3664 
3665 #undef __FUNCT__
3666 #define __FUNCT__ "TSComputeIJacobianConstant"
3667 /*@C
3668    TSComputeIJacobianConstant - Reuses a time-independent for a semi-implicit DAE or ODE
3669 
3670    Collective on TS
3671 
3672    Input Arguments:
3673 +  ts - time stepping context
3674 .  t - time at which to evaluate
3675 .  U - state at which to evaluate
3676 .  Udot - time derivative of state vector
3677 .  shift - shift to apply
3678 -  ctx - context
3679 
3680    Output Arguments:
3681 +  A - pointer to operator
3682 .  B - pointer to preconditioning matrix
3683 -  flg - matrix structure flag
3684 
3685    Level: advanced
3686 
3687    Notes:
3688    This function is intended to be passed to TSSetIJacobian() to evaluate the Jacobian for linear time-independent problems.
3689 
3690    It is only appropriate for problems of the form
3691 
3692 $     M Udot = F(U,t)
3693 
3694   where M is constant and F is non-stiff.  The user must pass M to TSSetIJacobian().  The current implementation only
3695   works with IMEX time integration methods such as TSROSW and TSARKIMEX, since there is no support for de-constructing
3696   an implicit operator of the form
3697 
3698 $    shift*M + J
3699 
3700   where J is the Jacobian of -F(U).  Support may be added in a future version of PETSc, but for now, the user must store
3701   a copy of M or reassemble it when requested.
3702 
3703 .seealso: TSSetIFunction(), TSSetIJacobian(), TSComputeIFunctionLinear()
3704 @*/
3705 PetscErrorCode TSComputeIJacobianConstant(TS ts,PetscReal t,Vec U,Vec Udot,PetscReal shift,Mat A,Mat B,void *ctx)
3706 {
3707   PetscErrorCode ierr;
3708 
3709   PetscFunctionBegin;
3710   ierr = MatScale(A, shift / ts->ijacobian.shift);CHKERRQ(ierr);
3711   ts->ijacobian.shift = shift;
3712   PetscFunctionReturn(0);
3713 }
3714 
3715 #undef __FUNCT__
3716 #define __FUNCT__ "TSGetEquationType"
3717 /*@
3718    TSGetEquationType - Gets the type of the equation that TS is solving.
3719 
3720    Not Collective
3721 
3722    Input Parameter:
3723 .  ts - the TS context
3724 
3725    Output Parameter:
3726 .  equation_type - see TSEquationType
3727 
3728    Level: beginner
3729 
3730 .keywords: TS, equation type
3731 
3732 .seealso: TSSetEquationType(), TSEquationType
3733 @*/
3734 PetscErrorCode  TSGetEquationType(TS ts,TSEquationType *equation_type)
3735 {
3736   PetscFunctionBegin;
3737   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3738   PetscValidPointer(equation_type,2);
3739   *equation_type = ts->equation_type;
3740   PetscFunctionReturn(0);
3741 }
3742 
3743 #undef __FUNCT__
3744 #define __FUNCT__ "TSSetEquationType"
3745 /*@
3746    TSSetEquationType - Sets the type of the equation that TS is solving.
3747 
3748    Not Collective
3749 
3750    Input Parameter:
3751 +  ts - the TS context
3752 .  equation_type - see TSEquationType
3753 
3754    Level: advanced
3755 
3756 .keywords: TS, equation type
3757 
3758 .seealso: TSGetEquationType(), TSEquationType
3759 @*/
3760 PetscErrorCode  TSSetEquationType(TS ts,TSEquationType equation_type)
3761 {
3762   PetscFunctionBegin;
3763   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3764   ts->equation_type = equation_type;
3765   PetscFunctionReturn(0);
3766 }
3767 
3768 #undef __FUNCT__
3769 #define __FUNCT__ "TSGetConvergedReason"
3770 /*@
3771    TSGetConvergedReason - Gets the reason the TS iteration was stopped.
3772 
3773    Not Collective
3774 
3775    Input Parameter:
3776 .  ts - the TS context
3777 
3778    Output Parameter:
3779 .  reason - negative value indicates diverged, positive value converged, see TSConvergedReason or the
3780             manual pages for the individual convergence tests for complete lists
3781 
3782    Level: beginner
3783 
3784    Notes:
3785    Can only be called after the call to TSSolve() is complete.
3786 
3787 .keywords: TS, nonlinear, set, convergence, test
3788 
3789 .seealso: TSSetConvergenceTest(), TSConvergedReason
3790 @*/
3791 PetscErrorCode  TSGetConvergedReason(TS ts,TSConvergedReason *reason)
3792 {
3793   PetscFunctionBegin;
3794   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3795   PetscValidPointer(reason,2);
3796   *reason = ts->reason;
3797   PetscFunctionReturn(0);
3798 }
3799 
3800 #undef __FUNCT__
3801 #define __FUNCT__ "TSSetConvergedReason"
3802 /*@
3803    TSSetConvergedReason - Sets the reason for handling the convergence of TSSolve.
3804 
3805    Not Collective
3806 
3807    Input Parameter:
3808 +  ts - the TS context
3809 .  reason - negative value indicates diverged, positive value converged, see TSConvergedReason or the
3810             manual pages for the individual convergence tests for complete lists
3811 
3812    Level: advanced
3813 
3814    Notes:
3815    Can only be called during TSSolve() is active.
3816 
3817 .keywords: TS, nonlinear, set, convergence, test
3818 
3819 .seealso: TSConvergedReason
3820 @*/
3821 PetscErrorCode  TSSetConvergedReason(TS ts,TSConvergedReason reason)
3822 {
3823   PetscFunctionBegin;
3824   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3825   ts->reason = reason;
3826   PetscFunctionReturn(0);
3827 }
3828 
3829 #undef __FUNCT__
3830 #define __FUNCT__ "TSGetSolveTime"
3831 /*@
3832    TSGetSolveTime - Gets the time after a call to TSSolve()
3833 
3834    Not Collective
3835 
3836    Input Parameter:
3837 .  ts - the TS context
3838 
3839    Output Parameter:
3840 .  ftime - the final time. This time should correspond to the final time set with TSSetDuration()
3841 
3842    Level: beginner
3843 
3844    Notes:
3845    Can only be called after the call to TSSolve() is complete.
3846 
3847 .keywords: TS, nonlinear, set, convergence, test
3848 
3849 .seealso: TSSetConvergenceTest(), TSConvergedReason
3850 @*/
3851 PetscErrorCode  TSGetSolveTime(TS ts,PetscReal *ftime)
3852 {
3853   PetscFunctionBegin;
3854   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3855   PetscValidPointer(ftime,2);
3856   *ftime = ts->solvetime;
3857   PetscFunctionReturn(0);
3858 }
3859 
3860 #undef __FUNCT__
3861 #define __FUNCT__ "TSGetSNESIterations"
3862 /*@
3863    TSGetSNESIterations - Gets the total number of nonlinear iterations
3864    used by the time integrator.
3865 
3866    Not Collective
3867 
3868    Input Parameter:
3869 .  ts - TS context
3870 
3871    Output Parameter:
3872 .  nits - number of nonlinear iterations
3873 
3874    Notes:
3875    This counter is reset to zero for each successive call to TSSolve().
3876 
3877    Level: intermediate
3878 
3879 .keywords: TS, get, number, nonlinear, iterations
3880 
3881 .seealso:  TSGetKSPIterations()
3882 @*/
3883 PetscErrorCode TSGetSNESIterations(TS ts,PetscInt *nits)
3884 {
3885   PetscFunctionBegin;
3886   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3887   PetscValidIntPointer(nits,2);
3888   *nits = ts->snes_its;
3889   PetscFunctionReturn(0);
3890 }
3891 
3892 #undef __FUNCT__
3893 #define __FUNCT__ "TSGetKSPIterations"
3894 /*@
3895    TSGetKSPIterations - Gets the total number of linear iterations
3896    used by the time integrator.
3897 
3898    Not Collective
3899 
3900    Input Parameter:
3901 .  ts - TS context
3902 
3903    Output Parameter:
3904 .  lits - number of linear iterations
3905 
3906    Notes:
3907    This counter is reset to zero for each successive call to TSSolve().
3908 
3909    Level: intermediate
3910 
3911 .keywords: TS, get, number, linear, iterations
3912 
3913 .seealso:  TSGetSNESIterations(), SNESGetKSPIterations()
3914 @*/
3915 PetscErrorCode TSGetKSPIterations(TS ts,PetscInt *lits)
3916 {
3917   PetscFunctionBegin;
3918   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3919   PetscValidIntPointer(lits,2);
3920   *lits = ts->ksp_its;
3921   PetscFunctionReturn(0);
3922 }
3923 
3924 #undef __FUNCT__
3925 #define __FUNCT__ "TSGetStepRejections"
3926 /*@
3927    TSGetStepRejections - Gets the total number of rejected steps.
3928 
3929    Not Collective
3930 
3931    Input Parameter:
3932 .  ts - TS context
3933 
3934    Output Parameter:
3935 .  rejects - number of steps rejected
3936 
3937    Notes:
3938    This counter is reset to zero for each successive call to TSSolve().
3939 
3940    Level: intermediate
3941 
3942 .keywords: TS, get, number
3943 
3944 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetSNESFailures(), TSSetMaxSNESFailures(), TSSetErrorIfStepFails()
3945 @*/
3946 PetscErrorCode TSGetStepRejections(TS ts,PetscInt *rejects)
3947 {
3948   PetscFunctionBegin;
3949   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3950   PetscValidIntPointer(rejects,2);
3951   *rejects = ts->reject;
3952   PetscFunctionReturn(0);
3953 }
3954 
3955 #undef __FUNCT__
3956 #define __FUNCT__ "TSGetSNESFailures"
3957 /*@
3958    TSGetSNESFailures - Gets the total number of failed SNES solves
3959 
3960    Not Collective
3961 
3962    Input Parameter:
3963 .  ts - TS context
3964 
3965    Output Parameter:
3966 .  fails - number of failed nonlinear solves
3967 
3968    Notes:
3969    This counter is reset to zero for each successive call to TSSolve().
3970 
3971    Level: intermediate
3972 
3973 .keywords: TS, get, number
3974 
3975 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSSetMaxSNESFailures()
3976 @*/
3977 PetscErrorCode TSGetSNESFailures(TS ts,PetscInt *fails)
3978 {
3979   PetscFunctionBegin;
3980   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3981   PetscValidIntPointer(fails,2);
3982   *fails = ts->num_snes_failures;
3983   PetscFunctionReturn(0);
3984 }
3985 
3986 #undef __FUNCT__
3987 #define __FUNCT__ "TSSetMaxStepRejections"
3988 /*@
3989    TSSetMaxStepRejections - Sets the maximum number of step rejections before a step fails
3990 
3991    Not Collective
3992 
3993    Input Parameter:
3994 +  ts - TS context
3995 -  rejects - maximum number of rejected steps, pass -1 for unlimited
3996 
3997    Notes:
3998    The counter is reset to zero for each step
3999 
4000    Options Database Key:
4001  .  -ts_max_reject - Maximum number of step rejections before a step fails
4002 
4003    Level: intermediate
4004 
4005 .keywords: TS, set, maximum, number
4006 
4007 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxSNESFailures(), TSGetStepRejections(), TSGetSNESFailures(), TSSetErrorIfStepFails(), TSGetConvergedReason()
4008 @*/
4009 PetscErrorCode TSSetMaxStepRejections(TS ts,PetscInt rejects)
4010 {
4011   PetscFunctionBegin;
4012   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4013   ts->max_reject = rejects;
4014   PetscFunctionReturn(0);
4015 }
4016 
4017 #undef __FUNCT__
4018 #define __FUNCT__ "TSSetMaxSNESFailures"
4019 /*@
4020    TSSetMaxSNESFailures - Sets the maximum number of failed SNES solves
4021 
4022    Not Collective
4023 
4024    Input Parameter:
4025 +  ts - TS context
4026 -  fails - maximum number of failed nonlinear solves, pass -1 for unlimited
4027 
4028    Notes:
4029    The counter is reset to zero for each successive call to TSSolve().
4030 
4031    Options Database Key:
4032  .  -ts_max_snes_failures - Maximum number of nonlinear solve failures
4033 
4034    Level: intermediate
4035 
4036 .keywords: TS, set, maximum, number
4037 
4038 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSGetSNESFailures(), SNESGetConvergedReason(), TSGetConvergedReason()
4039 @*/
4040 PetscErrorCode TSSetMaxSNESFailures(TS ts,PetscInt fails)
4041 {
4042   PetscFunctionBegin;
4043   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4044   ts->max_snes_failures = fails;
4045   PetscFunctionReturn(0);
4046 }
4047 
4048 #undef __FUNCT__
4049 #define __FUNCT__ "TSSetErrorIfStepFails"
4050 /*@
4051    TSSetErrorIfStepFails - Error if no step succeeds
4052 
4053    Not Collective
4054 
4055    Input Parameter:
4056 +  ts - TS context
4057 -  err - PETSC_TRUE to error if no step succeeds, PETSC_FALSE to return without failure
4058 
4059    Options Database Key:
4060  .  -ts_error_if_step_fails - Error if no step succeeds
4061 
4062    Level: intermediate
4063 
4064 .keywords: TS, set, error
4065 
4066 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSGetSNESFailures(), TSSetErrorIfStepFails(), TSGetConvergedReason()
4067 @*/
4068 PetscErrorCode TSSetErrorIfStepFails(TS ts,PetscBool err)
4069 {
4070   PetscFunctionBegin;
4071   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4072   ts->errorifstepfailed = err;
4073   PetscFunctionReturn(0);
4074 }
4075 
4076 #undef __FUNCT__
4077 #define __FUNCT__ "TSMonitorSolutionBinary"
4078 /*@C
4079    TSMonitorSolutionBinary - Monitors progress of the TS solvers by VecView() for the solution at each timestep. Normally the viewer is a binary file
4080 
4081    Collective on TS
4082 
4083    Input Parameters:
4084 +  ts - the TS context
4085 .  step - current time-step
4086 .  ptime - current time
4087 .  u - current state
4088 -  viewer - binary viewer
4089 
4090    Level: intermediate
4091 
4092 .keywords: TS,  vector, monitor, view
4093 
4094 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
4095 @*/
4096 PetscErrorCode  TSMonitorSolutionBinary(TS ts,PetscInt step,PetscReal ptime,Vec u,void *viewer)
4097 {
4098   PetscErrorCode ierr;
4099   PetscViewer    v = (PetscViewer)viewer;
4100 
4101   PetscFunctionBegin;
4102   ierr = VecView(u,v);CHKERRQ(ierr);
4103   PetscFunctionReturn(0);
4104 }
4105 
4106 #undef __FUNCT__
4107 #define __FUNCT__ "TSMonitorSolutionVTK"
4108 /*@C
4109    TSMonitorSolutionVTK - Monitors progress of the TS solvers by VecView() for the solution at each timestep.
4110 
4111    Collective on TS
4112 
4113    Input Parameters:
4114 +  ts - the TS context
4115 .  step - current time-step
4116 .  ptime - current time
4117 .  u - current state
4118 -  filenametemplate - string containing a format specifier for the integer time step (e.g. %03D)
4119 
4120    Level: intermediate
4121 
4122    Notes:
4123    The VTK format does not allow writing multiple time steps in the same file, therefore a different file will be written for each time step.
4124    These are named according to the file name template.
4125 
4126    This function is normally passed as an argument to TSMonitorSet() along with TSMonitorSolutionVTKDestroy().
4127 
4128 .keywords: TS,  vector, monitor, view
4129 
4130 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
4131 @*/
4132 PetscErrorCode TSMonitorSolutionVTK(TS ts,PetscInt step,PetscReal ptime,Vec u,void *filenametemplate)
4133 {
4134   PetscErrorCode ierr;
4135   char           filename[PETSC_MAX_PATH_LEN];
4136   PetscViewer    viewer;
4137 
4138   PetscFunctionBegin;
4139   ierr = PetscSNPrintf(filename,sizeof(filename),(const char*)filenametemplate,step);CHKERRQ(ierr);
4140   ierr = PetscViewerVTKOpen(PetscObjectComm((PetscObject)ts),filename,FILE_MODE_WRITE,&viewer);CHKERRQ(ierr);
4141   ierr = VecView(u,viewer);CHKERRQ(ierr);
4142   ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
4143   PetscFunctionReturn(0);
4144 }
4145 
4146 #undef __FUNCT__
4147 #define __FUNCT__ "TSMonitorSolutionVTKDestroy"
4148 /*@C
4149    TSMonitorSolutionVTKDestroy - Destroy context for monitoring
4150 
4151    Collective on TS
4152 
4153    Input Parameters:
4154 .  filenametemplate - string containing a format specifier for the integer time step (e.g. %03D)
4155 
4156    Level: intermediate
4157 
4158    Note:
4159    This function is normally passed to TSMonitorSet() along with TSMonitorSolutionVTK().
4160 
4161 .keywords: TS,  vector, monitor, view
4162 
4163 .seealso: TSMonitorSet(), TSMonitorSolutionVTK()
4164 @*/
4165 PetscErrorCode TSMonitorSolutionVTKDestroy(void *filenametemplate)
4166 {
4167   PetscErrorCode ierr;
4168 
4169   PetscFunctionBegin;
4170   ierr = PetscFree(*(char**)filenametemplate);CHKERRQ(ierr);
4171   PetscFunctionReturn(0);
4172 }
4173 
4174 #undef __FUNCT__
4175 #define __FUNCT__ "TSGetAdapt"
4176 /*@
4177    TSGetAdapt - Get the adaptive controller context for the current method
4178 
4179    Collective on TS if controller has not been created yet
4180 
4181    Input Arguments:
4182 .  ts - time stepping context
4183 
4184    Output Arguments:
4185 .  adapt - adaptive controller
4186 
4187    Level: intermediate
4188 
4189 .seealso: TSAdapt, TSAdaptSetType(), TSAdaptChoose()
4190 @*/
4191 PetscErrorCode TSGetAdapt(TS ts,TSAdapt *adapt)
4192 {
4193   PetscErrorCode ierr;
4194 
4195   PetscFunctionBegin;
4196   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4197   PetscValidPointer(adapt,2);
4198   if (!ts->adapt) {
4199     ierr = TSAdaptCreate(PetscObjectComm((PetscObject)ts),&ts->adapt);CHKERRQ(ierr);
4200     ierr = PetscLogObjectParent((PetscObject)ts,(PetscObject)ts->adapt);CHKERRQ(ierr);
4201     ierr = PetscObjectIncrementTabLevel((PetscObject)ts->adapt,(PetscObject)ts,1);CHKERRQ(ierr);
4202   }
4203   *adapt = ts->adapt;
4204   PetscFunctionReturn(0);
4205 }
4206 
4207 #undef __FUNCT__
4208 #define __FUNCT__ "TSSetTolerances"
4209 /*@
4210    TSSetTolerances - Set tolerances for local truncation error when using adaptive controller
4211 
4212    Logically Collective
4213 
4214    Input Arguments:
4215 +  ts - time integration context
4216 .  atol - scalar absolute tolerances, PETSC_DECIDE to leave current value
4217 .  vatol - vector of absolute tolerances or NULL, used in preference to atol if present
4218 .  rtol - scalar relative tolerances, PETSC_DECIDE to leave current value
4219 -  vrtol - vector of relative tolerances or NULL, used in preference to atol if present
4220 
4221    Options Database keys:
4222 +  -ts_rtol <rtol> - relative tolerance for local truncation error
4223 -  -ts_atol <atol> Absolute tolerance for local truncation error
4224 
4225    Level: beginner
4226 
4227 .seealso: TS, TSAdapt, TSVecNormWRMS(), TSGetTolerances()
4228 @*/
4229 PetscErrorCode TSSetTolerances(TS ts,PetscReal atol,Vec vatol,PetscReal rtol,Vec vrtol)
4230 {
4231   PetscErrorCode ierr;
4232 
4233   PetscFunctionBegin;
4234   if (atol != PETSC_DECIDE && atol != PETSC_DEFAULT) ts->atol = atol;
4235   if (vatol) {
4236     ierr = PetscObjectReference((PetscObject)vatol);CHKERRQ(ierr);
4237     ierr = VecDestroy(&ts->vatol);CHKERRQ(ierr);
4238 
4239     ts->vatol = vatol;
4240   }
4241   if (rtol != PETSC_DECIDE && rtol != PETSC_DEFAULT) ts->rtol = rtol;
4242   if (vrtol) {
4243     ierr = PetscObjectReference((PetscObject)vrtol);CHKERRQ(ierr);
4244     ierr = VecDestroy(&ts->vrtol);CHKERRQ(ierr);
4245 
4246     ts->vrtol = vrtol;
4247   }
4248   PetscFunctionReturn(0);
4249 }
4250 
4251 #undef __FUNCT__
4252 #define __FUNCT__ "TSGetTolerances"
4253 /*@
4254    TSGetTolerances - Get tolerances for local truncation error when using adaptive controller
4255 
4256    Logically Collective
4257 
4258    Input Arguments:
4259 .  ts - time integration context
4260 
4261    Output Arguments:
4262 +  atol - scalar absolute tolerances, NULL to ignore
4263 .  vatol - vector of absolute tolerances, NULL to ignore
4264 .  rtol - scalar relative tolerances, NULL to ignore
4265 -  vrtol - vector of relative tolerances, NULL to ignore
4266 
4267    Level: beginner
4268 
4269 .seealso: TS, TSAdapt, TSVecNormWRMS(), TSSetTolerances()
4270 @*/
4271 PetscErrorCode TSGetTolerances(TS ts,PetscReal *atol,Vec *vatol,PetscReal *rtol,Vec *vrtol)
4272 {
4273   PetscFunctionBegin;
4274   if (atol)  *atol  = ts->atol;
4275   if (vatol) *vatol = ts->vatol;
4276   if (rtol)  *rtol  = ts->rtol;
4277   if (vrtol) *vrtol = ts->vrtol;
4278   PetscFunctionReturn(0);
4279 }
4280 
4281 #undef __FUNCT__
4282 #define __FUNCT__ "TSErrorNormWRMS"
4283 /*@
4284    TSErrorNormWRMS - compute a weighted norm of the difference between a vector and the current state
4285 
4286    Collective on TS
4287 
4288    Input Arguments:
4289 +  ts - time stepping context
4290 -  Y - state vector to be compared to ts->vec_sol
4291 
4292    Output Arguments:
4293 .  norm - weighted norm, a value of 1.0 is considered small
4294 
4295    Level: developer
4296 
4297 .seealso: TSSetTolerances()
4298 @*/
4299 PetscErrorCode TSErrorNormWRMS(TS ts,Vec Y,PetscReal *norm)
4300 {
4301   PetscErrorCode    ierr;
4302   PetscInt          i,n,N;
4303   const PetscScalar *u,*y;
4304   Vec               U;
4305   PetscReal         sum,gsum;
4306 
4307   PetscFunctionBegin;
4308   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4309   PetscValidHeaderSpecific(Y,VEC_CLASSID,2);
4310   PetscValidPointer(norm,3);
4311   U = ts->vec_sol;
4312   PetscCheckSameTypeAndComm(U,1,Y,2);
4313   if (U == Y) SETERRQ(PetscObjectComm((PetscObject)U),PETSC_ERR_ARG_IDN,"Y cannot be the TS solution vector");
4314 
4315   ierr = VecGetSize(U,&N);CHKERRQ(ierr);
4316   ierr = VecGetLocalSize(U,&n);CHKERRQ(ierr);
4317   ierr = VecGetArrayRead(U,&u);CHKERRQ(ierr);
4318   ierr = VecGetArrayRead(Y,&y);CHKERRQ(ierr);
4319   sum  = 0.;
4320   if (ts->vatol && ts->vrtol) {
4321     const PetscScalar *atol,*rtol;
4322     ierr = VecGetArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4323     ierr = VecGetArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4324     for (i=0; i<n; i++) {
4325       PetscReal tol = PetscRealPart(atol[i]) + PetscRealPart(rtol[i]) * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4326       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4327     }
4328     ierr = VecRestoreArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4329     ierr = VecRestoreArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4330   } else if (ts->vatol) {       /* vector atol, scalar rtol */
4331     const PetscScalar *atol;
4332     ierr = VecGetArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4333     for (i=0; i<n; i++) {
4334       PetscReal tol = PetscRealPart(atol[i]) + ts->rtol * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4335       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4336     }
4337     ierr = VecRestoreArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4338   } else if (ts->vrtol) {       /* scalar atol, vector rtol */
4339     const PetscScalar *rtol;
4340     ierr = VecGetArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4341     for (i=0; i<n; i++) {
4342       PetscReal tol = ts->atol + PetscRealPart(rtol[i]) * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4343       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4344     }
4345     ierr = VecRestoreArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4346   } else {                      /* scalar atol, scalar rtol */
4347     for (i=0; i<n; i++) {
4348       PetscReal tol = ts->atol + ts->rtol * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4349       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4350     }
4351   }
4352   ierr = VecRestoreArrayRead(U,&u);CHKERRQ(ierr);
4353   ierr = VecRestoreArrayRead(Y,&y);CHKERRQ(ierr);
4354 
4355   ierr  = MPI_Allreduce(&sum,&gsum,1,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)ts));CHKERRQ(ierr);
4356   *norm = PetscSqrtReal(gsum / N);
4357   if (PetscIsInfOrNanReal(*norm)) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_FP,"Infinite or not-a-number generated in norm");
4358   PetscFunctionReturn(0);
4359 }
4360 
4361 #undef __FUNCT__
4362 #define __FUNCT__ "TSSetCFLTimeLocal"
4363 /*@
4364    TSSetCFLTimeLocal - Set the local CFL constraint relative to forward Euler
4365 
4366    Logically Collective on TS
4367 
4368    Input Arguments:
4369 +  ts - time stepping context
4370 -  cfltime - maximum stable time step if using forward Euler (value can be different on each process)
4371 
4372    Note:
4373    After calling this function, the global CFL time can be obtained by calling TSGetCFLTime()
4374 
4375    Level: intermediate
4376 
4377 .seealso: TSGetCFLTime(), TSADAPTCFL
4378 @*/
4379 PetscErrorCode TSSetCFLTimeLocal(TS ts,PetscReal cfltime)
4380 {
4381   PetscFunctionBegin;
4382   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4383   ts->cfltime_local = cfltime;
4384   ts->cfltime       = -1.;
4385   PetscFunctionReturn(0);
4386 }
4387 
4388 #undef __FUNCT__
4389 #define __FUNCT__ "TSGetCFLTime"
4390 /*@
4391    TSGetCFLTime - Get the maximum stable time step according to CFL criteria applied to forward Euler
4392 
4393    Collective on TS
4394 
4395    Input Arguments:
4396 .  ts - time stepping context
4397 
4398    Output Arguments:
4399 .  cfltime - maximum stable time step for forward Euler
4400 
4401    Level: advanced
4402 
4403 .seealso: TSSetCFLTimeLocal()
4404 @*/
4405 PetscErrorCode TSGetCFLTime(TS ts,PetscReal *cfltime)
4406 {
4407   PetscErrorCode ierr;
4408 
4409   PetscFunctionBegin;
4410   if (ts->cfltime < 0) {
4411     ierr = MPI_Allreduce(&ts->cfltime_local,&ts->cfltime,1,MPIU_REAL,MPIU_MIN,PetscObjectComm((PetscObject)ts));CHKERRQ(ierr);
4412   }
4413   *cfltime = ts->cfltime;
4414   PetscFunctionReturn(0);
4415 }
4416 
4417 #undef __FUNCT__
4418 #define __FUNCT__ "TSVISetVariableBounds"
4419 /*@
4420    TSVISetVariableBounds - Sets the lower and upper bounds for the solution vector. xl <= x <= xu
4421 
4422    Input Parameters:
4423 .  ts   - the TS context.
4424 .  xl   - lower bound.
4425 .  xu   - upper bound.
4426 
4427    Notes:
4428    If this routine is not called then the lower and upper bounds are set to
4429    PETSC_NINFINITY and PETSC_INFINITY respectively during SNESSetUp().
4430 
4431    Level: advanced
4432 
4433 @*/
4434 PetscErrorCode TSVISetVariableBounds(TS ts, Vec xl, Vec xu)
4435 {
4436   PetscErrorCode ierr;
4437   SNES           snes;
4438 
4439   PetscFunctionBegin;
4440   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
4441   ierr = SNESVISetVariableBounds(snes,xl,xu);CHKERRQ(ierr);
4442   PetscFunctionReturn(0);
4443 }
4444 
4445 #if defined(PETSC_HAVE_MATLAB_ENGINE)
4446 #include <mex.h>
4447 
4448 typedef struct {char *funcname; mxArray *ctx;} TSMatlabContext;
4449 
4450 #undef __FUNCT__
4451 #define __FUNCT__ "TSComputeFunction_Matlab"
4452 /*
4453    TSComputeFunction_Matlab - Calls the function that has been set with
4454                          TSSetFunctionMatlab().
4455 
4456    Collective on TS
4457 
4458    Input Parameters:
4459 +  snes - the TS context
4460 -  u - input vector
4461 
4462    Output Parameter:
4463 .  y - function vector, as set by TSSetFunction()
4464 
4465    Notes:
4466    TSComputeFunction() is typically used within nonlinear solvers
4467    implementations, so most users would not generally call this routine
4468    themselves.
4469 
4470    Level: developer
4471 
4472 .keywords: TS, nonlinear, compute, function
4473 
4474 .seealso: TSSetFunction(), TSGetFunction()
4475 */
4476 PetscErrorCode  TSComputeFunction_Matlab(TS snes,PetscReal time,Vec u,Vec udot,Vec y, void *ctx)
4477 {
4478   PetscErrorCode  ierr;
4479   TSMatlabContext *sctx = (TSMatlabContext*)ctx;
4480   int             nlhs  = 1,nrhs = 7;
4481   mxArray         *plhs[1],*prhs[7];
4482   long long int   lx = 0,lxdot = 0,ly = 0,ls = 0;
4483 
4484   PetscFunctionBegin;
4485   PetscValidHeaderSpecific(snes,TS_CLASSID,1);
4486   PetscValidHeaderSpecific(u,VEC_CLASSID,3);
4487   PetscValidHeaderSpecific(udot,VEC_CLASSID,4);
4488   PetscValidHeaderSpecific(y,VEC_CLASSID,5);
4489   PetscCheckSameComm(snes,1,u,3);
4490   PetscCheckSameComm(snes,1,y,5);
4491 
4492   ierr = PetscMemcpy(&ls,&snes,sizeof(snes));CHKERRQ(ierr);
4493   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4494   ierr = PetscMemcpy(&lxdot,&udot,sizeof(udot));CHKERRQ(ierr);
4495   ierr = PetscMemcpy(&ly,&y,sizeof(u));CHKERRQ(ierr);
4496 
4497   prhs[0] =  mxCreateDoubleScalar((double)ls);
4498   prhs[1] =  mxCreateDoubleScalar(time);
4499   prhs[2] =  mxCreateDoubleScalar((double)lx);
4500   prhs[3] =  mxCreateDoubleScalar((double)lxdot);
4501   prhs[4] =  mxCreateDoubleScalar((double)ly);
4502   prhs[5] =  mxCreateString(sctx->funcname);
4503   prhs[6] =  sctx->ctx;
4504   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSComputeFunctionInternal");CHKERRQ(ierr);
4505   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4506   mxDestroyArray(prhs[0]);
4507   mxDestroyArray(prhs[1]);
4508   mxDestroyArray(prhs[2]);
4509   mxDestroyArray(prhs[3]);
4510   mxDestroyArray(prhs[4]);
4511   mxDestroyArray(prhs[5]);
4512   mxDestroyArray(plhs[0]);
4513   PetscFunctionReturn(0);
4514 }
4515 
4516 
4517 #undef __FUNCT__
4518 #define __FUNCT__ "TSSetFunctionMatlab"
4519 /*
4520    TSSetFunctionMatlab - Sets the function evaluation routine and function
4521    vector for use by the TS routines in solving ODEs
4522    equations from MATLAB. Here the function is a string containing the name of a MATLAB function
4523 
4524    Logically Collective on TS
4525 
4526    Input Parameters:
4527 +  ts - the TS context
4528 -  func - function evaluation routine
4529 
4530    Calling sequence of func:
4531 $    func (TS ts,PetscReal time,Vec u,Vec udot,Vec f,void *ctx);
4532 
4533    Level: beginner
4534 
4535 .keywords: TS, nonlinear, set, function
4536 
4537 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4538 */
4539 PetscErrorCode  TSSetFunctionMatlab(TS ts,const char *func,mxArray *ctx)
4540 {
4541   PetscErrorCode  ierr;
4542   TSMatlabContext *sctx;
4543 
4544   PetscFunctionBegin;
4545   /* currently sctx is memory bleed */
4546   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4547   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4548   /*
4549      This should work, but it doesn't
4550   sctx->ctx = ctx;
4551   mexMakeArrayPersistent(sctx->ctx);
4552   */
4553   sctx->ctx = mxDuplicateArray(ctx);
4554 
4555   ierr = TSSetIFunction(ts,NULL,TSComputeFunction_Matlab,sctx);CHKERRQ(ierr);
4556   PetscFunctionReturn(0);
4557 }
4558 
4559 #undef __FUNCT__
4560 #define __FUNCT__ "TSComputeJacobian_Matlab"
4561 /*
4562    TSComputeJacobian_Matlab - Calls the function that has been set with
4563                          TSSetJacobianMatlab().
4564 
4565    Collective on TS
4566 
4567    Input Parameters:
4568 +  ts - the TS context
4569 .  u - input vector
4570 .  A, B - the matrices
4571 -  ctx - user context
4572 
4573    Level: developer
4574 
4575 .keywords: TS, nonlinear, compute, function
4576 
4577 .seealso: TSSetFunction(), TSGetFunction()
4578 @*/
4579 PetscErrorCode  TSComputeJacobian_Matlab(TS ts,PetscReal time,Vec u,Vec udot,PetscReal shift,Mat A,Mat B,void *ctx)
4580 {
4581   PetscErrorCode  ierr;
4582   TSMatlabContext *sctx = (TSMatlabContext*)ctx;
4583   int             nlhs  = 2,nrhs = 9;
4584   mxArray         *plhs[2],*prhs[9];
4585   long long int   lx = 0,lxdot = 0,lA = 0,ls = 0, lB = 0;
4586 
4587   PetscFunctionBegin;
4588   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4589   PetscValidHeaderSpecific(u,VEC_CLASSID,3);
4590 
4591   /* call Matlab function in ctx with arguments u and y */
4592 
4593   ierr = PetscMemcpy(&ls,&ts,sizeof(ts));CHKERRQ(ierr);
4594   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4595   ierr = PetscMemcpy(&lxdot,&udot,sizeof(u));CHKERRQ(ierr);
4596   ierr = PetscMemcpy(&lA,A,sizeof(u));CHKERRQ(ierr);
4597   ierr = PetscMemcpy(&lB,B,sizeof(u));CHKERRQ(ierr);
4598 
4599   prhs[0] =  mxCreateDoubleScalar((double)ls);
4600   prhs[1] =  mxCreateDoubleScalar((double)time);
4601   prhs[2] =  mxCreateDoubleScalar((double)lx);
4602   prhs[3] =  mxCreateDoubleScalar((double)lxdot);
4603   prhs[4] =  mxCreateDoubleScalar((double)shift);
4604   prhs[5] =  mxCreateDoubleScalar((double)lA);
4605   prhs[6] =  mxCreateDoubleScalar((double)lB);
4606   prhs[7] =  mxCreateString(sctx->funcname);
4607   prhs[8] =  sctx->ctx;
4608   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSComputeJacobianInternal");CHKERRQ(ierr);
4609   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4610   mxDestroyArray(prhs[0]);
4611   mxDestroyArray(prhs[1]);
4612   mxDestroyArray(prhs[2]);
4613   mxDestroyArray(prhs[3]);
4614   mxDestroyArray(prhs[4]);
4615   mxDestroyArray(prhs[5]);
4616   mxDestroyArray(prhs[6]);
4617   mxDestroyArray(prhs[7]);
4618   mxDestroyArray(plhs[0]);
4619   mxDestroyArray(plhs[1]);
4620   PetscFunctionReturn(0);
4621 }
4622 
4623 
4624 #undef __FUNCT__
4625 #define __FUNCT__ "TSSetJacobianMatlab"
4626 /*
4627    TSSetJacobianMatlab - Sets the Jacobian function evaluation routine and two empty Jacobian matrices
4628    vector for use by the TS routines in solving ODEs from MATLAB. Here the function is a string containing the name of a MATLAB function
4629 
4630    Logically Collective on TS
4631 
4632    Input Parameters:
4633 +  ts - the TS context
4634 .  A,B - Jacobian matrices
4635 .  func - function evaluation routine
4636 -  ctx - user context
4637 
4638    Calling sequence of func:
4639 $    flag = func (TS ts,PetscReal time,Vec u,Vec udot,Mat A,Mat B,void *ctx);
4640 
4641 
4642    Level: developer
4643 
4644 .keywords: TS, nonlinear, set, function
4645 
4646 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4647 */
4648 PetscErrorCode  TSSetJacobianMatlab(TS ts,Mat A,Mat B,const char *func,mxArray *ctx)
4649 {
4650   PetscErrorCode  ierr;
4651   TSMatlabContext *sctx;
4652 
4653   PetscFunctionBegin;
4654   /* currently sctx is memory bleed */
4655   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4656   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4657   /*
4658      This should work, but it doesn't
4659   sctx->ctx = ctx;
4660   mexMakeArrayPersistent(sctx->ctx);
4661   */
4662   sctx->ctx = mxDuplicateArray(ctx);
4663 
4664   ierr = TSSetIJacobian(ts,A,B,TSComputeJacobian_Matlab,sctx);CHKERRQ(ierr);
4665   PetscFunctionReturn(0);
4666 }
4667 
4668 #undef __FUNCT__
4669 #define __FUNCT__ "TSMonitor_Matlab"
4670 /*
4671    TSMonitor_Matlab - Calls the function that has been set with TSMonitorSetMatlab().
4672 
4673    Collective on TS
4674 
4675 .seealso: TSSetFunction(), TSGetFunction()
4676 @*/
4677 PetscErrorCode  TSMonitor_Matlab(TS ts,PetscInt it, PetscReal time,Vec u, void *ctx)
4678 {
4679   PetscErrorCode  ierr;
4680   TSMatlabContext *sctx = (TSMatlabContext*)ctx;
4681   int             nlhs  = 1,nrhs = 6;
4682   mxArray         *plhs[1],*prhs[6];
4683   long long int   lx = 0,ls = 0;
4684 
4685   PetscFunctionBegin;
4686   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4687   PetscValidHeaderSpecific(u,VEC_CLASSID,4);
4688 
4689   ierr = PetscMemcpy(&ls,&ts,sizeof(ts));CHKERRQ(ierr);
4690   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4691 
4692   prhs[0] =  mxCreateDoubleScalar((double)ls);
4693   prhs[1] =  mxCreateDoubleScalar((double)it);
4694   prhs[2] =  mxCreateDoubleScalar((double)time);
4695   prhs[3] =  mxCreateDoubleScalar((double)lx);
4696   prhs[4] =  mxCreateString(sctx->funcname);
4697   prhs[5] =  sctx->ctx;
4698   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSMonitorInternal");CHKERRQ(ierr);
4699   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4700   mxDestroyArray(prhs[0]);
4701   mxDestroyArray(prhs[1]);
4702   mxDestroyArray(prhs[2]);
4703   mxDestroyArray(prhs[3]);
4704   mxDestroyArray(prhs[4]);
4705   mxDestroyArray(plhs[0]);
4706   PetscFunctionReturn(0);
4707 }
4708 
4709 
4710 #undef __FUNCT__
4711 #define __FUNCT__ "TSMonitorSetMatlab"
4712 /*
4713    TSMonitorSetMatlab - Sets the monitor function from Matlab
4714 
4715    Level: developer
4716 
4717 .keywords: TS, nonlinear, set, function
4718 
4719 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4720 */
4721 PetscErrorCode  TSMonitorSetMatlab(TS ts,const char *func,mxArray *ctx)
4722 {
4723   PetscErrorCode  ierr;
4724   TSMatlabContext *sctx;
4725 
4726   PetscFunctionBegin;
4727   /* currently sctx is memory bleed */
4728   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4729   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4730   /*
4731      This should work, but it doesn't
4732   sctx->ctx = ctx;
4733   mexMakeArrayPersistent(sctx->ctx);
4734   */
4735   sctx->ctx = mxDuplicateArray(ctx);
4736 
4737   ierr = TSMonitorSet(ts,TSMonitor_Matlab,sctx,NULL);CHKERRQ(ierr);
4738   PetscFunctionReturn(0);
4739 }
4740 #endif
4741 
4742 
4743 
4744 #undef __FUNCT__
4745 #define __FUNCT__ "TSMonitorLGSolution"
4746 /*@C
4747    TSMonitorLGSolution - Monitors progress of the TS solvers by plotting each component of the solution vector
4748        in a time based line graph
4749 
4750    Collective on TS
4751 
4752    Input Parameters:
4753 +  ts - the TS context
4754 .  step - current time-step
4755 .  ptime - current time
4756 -  lg - a line graph object
4757 
4758    Level: intermediate
4759 
4760     Notes: each process in a parallel run displays its component solutions in a separate window
4761 
4762 .keywords: TS,  vector, monitor, view
4763 
4764 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
4765 @*/
4766 PetscErrorCode  TSMonitorLGSolution(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
4767 {
4768   PetscErrorCode    ierr;
4769   TSMonitorLGCtx    ctx = (TSMonitorLGCtx)dummy;
4770   const PetscScalar *yy;
4771   PetscInt          dim;
4772 
4773   PetscFunctionBegin;
4774   if (!step) {
4775     PetscDrawAxis axis;
4776     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4777     ierr = PetscDrawAxisSetLabels(axis,"Solution as function of time","Time","Solution");CHKERRQ(ierr);
4778     ierr = VecGetLocalSize(u,&dim);CHKERRQ(ierr);
4779     ierr = PetscDrawLGSetDimension(ctx->lg,dim);CHKERRQ(ierr);
4780     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4781   }
4782   ierr = VecGetArrayRead(u,&yy);CHKERRQ(ierr);
4783 #if defined(PETSC_USE_COMPLEX)
4784   {
4785     PetscReal *yreal;
4786     PetscInt  i,n;
4787     ierr = VecGetLocalSize(u,&n);CHKERRQ(ierr);
4788     ierr = PetscMalloc1(n,&yreal);CHKERRQ(ierr);
4789     for (i=0; i<n; i++) yreal[i] = PetscRealPart(yy[i]);
4790     ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yreal);CHKERRQ(ierr);
4791     ierr = PetscFree(yreal);CHKERRQ(ierr);
4792   }
4793 #else
4794   ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yy);CHKERRQ(ierr);
4795 #endif
4796   ierr = VecRestoreArrayRead(u,&yy);CHKERRQ(ierr);
4797   if (((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason)) {
4798     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4799   }
4800   PetscFunctionReturn(0);
4801 }
4802 
4803 #undef __FUNCT__
4804 #define __FUNCT__ "TSMonitorLGError"
4805 /*@C
4806    TSMonitorLGError - Monitors progress of the TS solvers by plotting each component of the solution vector
4807        in a time based line graph
4808 
4809    Collective on TS
4810 
4811    Input Parameters:
4812 +  ts - the TS context
4813 .  step - current time-step
4814 .  ptime - current time
4815 -  lg - a line graph object
4816 
4817    Level: intermediate
4818 
4819    Notes:
4820    Only for sequential solves.
4821 
4822    The user must provide the solution using TSSetSolutionFunction() to use this monitor.
4823 
4824    Options Database Keys:
4825 .  -ts_monitor_lg_error - create a graphical monitor of error history
4826 
4827 .keywords: TS,  vector, monitor, view
4828 
4829 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSSetSolutionFunction()
4830 @*/
4831 PetscErrorCode  TSMonitorLGError(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
4832 {
4833   PetscErrorCode    ierr;
4834   TSMonitorLGCtx    ctx = (TSMonitorLGCtx)dummy;
4835   const PetscScalar *yy;
4836   Vec               y;
4837   PetscInt          dim;
4838 
4839   PetscFunctionBegin;
4840   if (!step) {
4841     PetscDrawAxis axis;
4842     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4843     ierr = PetscDrawAxisSetLabels(axis,"Error in solution as function of time","Time","Solution");CHKERRQ(ierr);
4844     ierr = VecGetLocalSize(u,&dim);CHKERRQ(ierr);
4845     ierr = PetscDrawLGSetDimension(ctx->lg,dim);CHKERRQ(ierr);
4846     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4847   }
4848   ierr = VecDuplicate(u,&y);CHKERRQ(ierr);
4849   ierr = TSComputeSolutionFunction(ts,ptime,y);CHKERRQ(ierr);
4850   ierr = VecAXPY(y,-1.0,u);CHKERRQ(ierr);
4851   ierr = VecGetArrayRead(y,&yy);CHKERRQ(ierr);
4852 #if defined(PETSC_USE_COMPLEX)
4853   {
4854     PetscReal *yreal;
4855     PetscInt  i,n;
4856     ierr = VecGetLocalSize(y,&n);CHKERRQ(ierr);
4857     ierr = PetscMalloc1(n,&yreal);CHKERRQ(ierr);
4858     for (i=0; i<n; i++) yreal[i] = PetscRealPart(yy[i]);
4859     ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yreal);CHKERRQ(ierr);
4860     ierr = PetscFree(yreal);CHKERRQ(ierr);
4861   }
4862 #else
4863   ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yy);CHKERRQ(ierr);
4864 #endif
4865   ierr = VecRestoreArrayRead(y,&yy);CHKERRQ(ierr);
4866   ierr = VecDestroy(&y);CHKERRQ(ierr);
4867   if (((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason)) {
4868     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4869   }
4870   PetscFunctionReturn(0);
4871 }
4872 
4873 #undef __FUNCT__
4874 #define __FUNCT__ "TSMonitorLGSNESIterations"
4875 PetscErrorCode TSMonitorLGSNESIterations(TS ts,PetscInt n,PetscReal ptime,Vec v,void *monctx)
4876 {
4877   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
4878   PetscReal      x   = ptime,y;
4879   PetscErrorCode ierr;
4880   PetscInt       its;
4881 
4882   PetscFunctionBegin;
4883   if (!n) {
4884     PetscDrawAxis axis;
4885 
4886     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4887     ierr = PetscDrawAxisSetLabels(axis,"Nonlinear iterations as function of time","Time","SNES Iterations");CHKERRQ(ierr);
4888     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4889 
4890     ctx->snes_its = 0;
4891   }
4892   ierr = TSGetSNESIterations(ts,&its);CHKERRQ(ierr);
4893   y    = its - ctx->snes_its;
4894   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
4895   if (((ctx->howoften > 0) && (!(n % ctx->howoften)) && (n > -1)) || ((ctx->howoften == -1) && (n == -1))) {
4896     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4897   }
4898   ctx->snes_its = its;
4899   PetscFunctionReturn(0);
4900 }
4901 
4902 #undef __FUNCT__
4903 #define __FUNCT__ "TSMonitorLGKSPIterations"
4904 PetscErrorCode TSMonitorLGKSPIterations(TS ts,PetscInt n,PetscReal ptime,Vec v,void *monctx)
4905 {
4906   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
4907   PetscReal      x   = ptime,y;
4908   PetscErrorCode ierr;
4909   PetscInt       its;
4910 
4911   PetscFunctionBegin;
4912   if (!n) {
4913     PetscDrawAxis axis;
4914 
4915     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4916     ierr = PetscDrawAxisSetLabels(axis,"Linear iterations as function of time","Time","KSP Iterations");CHKERRQ(ierr);
4917     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4918 
4919     ctx->ksp_its = 0;
4920   }
4921   ierr = TSGetKSPIterations(ts,&its);CHKERRQ(ierr);
4922   y    = its - ctx->ksp_its;
4923   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
4924   if (((ctx->howoften > 0) && (!(n % ctx->howoften)) && (n > -1)) || ((ctx->howoften == -1) && (n == -1))) {
4925     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4926   }
4927   ctx->ksp_its = its;
4928   PetscFunctionReturn(0);
4929 }
4930 
4931 #undef __FUNCT__
4932 #define __FUNCT__ "TSComputeLinearStability"
4933 /*@
4934    TSComputeLinearStability - computes the linear stability function at a point
4935 
4936    Collective on TS and Vec
4937 
4938    Input Parameters:
4939 +  ts - the TS context
4940 -  xr,xi - real and imaginary part of input arguments
4941 
4942    Output Parameters:
4943 .  yr,yi - real and imaginary part of function value
4944 
4945    Level: developer
4946 
4947 .keywords: TS, compute
4948 
4949 .seealso: TSSetRHSFunction(), TSComputeIFunction()
4950 @*/
4951 PetscErrorCode TSComputeLinearStability(TS ts,PetscReal xr,PetscReal xi,PetscReal *yr,PetscReal *yi)
4952 {
4953   PetscErrorCode ierr;
4954 
4955   PetscFunctionBegin;
4956   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4957   if (!ts->ops->linearstability) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"Linearized stability function not provided for this method");
4958   ierr = (*ts->ops->linearstability)(ts,xr,xi,yr,yi);CHKERRQ(ierr);
4959   PetscFunctionReturn(0);
4960 }
4961 
4962 #undef __FUNCT__
4963 #define __FUNCT__ "TSRollBack"
4964 /*@
4965    TSRollBack - Rolls back one time step
4966 
4967    Collective on TS
4968 
4969    Input Parameter:
4970 .  ts - the TS context obtained from TSCreate()
4971 
4972    Level: advanced
4973 
4974 .keywords: TS, timestep, rollback
4975 
4976 .seealso: TSCreate(), TSSetUp(), TSDestroy(), TSSolve(), TSSetPreStep(), TSSetPreStage(), TSInterpolate()
4977 @*/
4978 PetscErrorCode  TSRollBack(TS ts)
4979 {
4980   PetscErrorCode ierr;
4981 
4982   PetscFunctionBegin;
4983   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
4984 
4985   if (!ts->ops->rollback) SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"TSRollBack not implemented for type '%s'",((PetscObject)ts)->type_name);
4986   ierr = (*ts->ops->rollback)(ts);CHKERRQ(ierr);
4987   ts->time_step = ts->ptime - ts->ptime_prev;
4988   ts->ptime = ts->ptime_prev;
4989   PetscFunctionReturn(0);
4990 }
4991 
4992