xref: /petsc/src/ts/interface/ts.c (revision f37c82fbca2ef2d9869799d3305350a5f272bd86)
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 = PetscOptionsList("-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_monitor - print information at each timestep
76 .  -ts_monitor_lg_timestep - Monitor timestep size graphically
77 .  -ts_monitor_lg_solution - Monitor solution graphically
78 .  -ts_monitor_lg_error - Monitor error graphically
79 .  -ts_monitor_lg_snes_iterations - Monitor number nonlinear iterations for each timestep graphically
80 .  -ts_monitor_lg_ksp_iterations - Monitor number nonlinear iterations for each timestep graphically
81 .  -ts_monitor_sp_eig - Monitor eigenvalues of linearized operator graphically
82 .  -ts_monitor_draw_solution - Monitor solution graphically
83 .  -ts_monitor_draw_solution_phase - Monitor solution graphically with phase diagram
84 .  -ts_monitor_draw_error - Monitor error graphically
85 .  -ts_monitor_solution_binary <filename> - Save each solution to a binary file
86 -  -ts_monitor_solution_vtk <filename.vts> - Save each time step to a binary file, use filename-%%03D.vts
87 
88    Developer Note: We should unify all the -ts_monitor options in the way that -xxx_view has been unified
89 
90    Level: beginner
91 
92 .keywords: TS, timestep, set, options, database
93 
94 .seealso: TSGetType()
95 @*/
96 PetscErrorCode  TSSetFromOptions(TS ts)
97 {
98   PetscBool              opt,flg;
99   PetscErrorCode         ierr;
100   PetscViewer            monviewer;
101   char                   monfilename[PETSC_MAX_PATH_LEN];
102   SNES                   snes;
103   TSAdapt                adapt;
104   PetscReal              time_step;
105   TSExactFinalTimeOption eftopt;
106   char                   dir[16];
107 
108   PetscFunctionBegin;
109   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
110   ierr = PetscObjectOptionsBegin((PetscObject)ts);CHKERRQ(ierr);
111   /* Handle TS type options */
112   ierr = TSSetTypeFromOptions(ts);CHKERRQ(ierr);
113 
114   /* Handle generic TS options */
115   ierr = PetscOptionsInt("-ts_max_steps","Maximum number of time steps","TSSetDuration",ts->max_steps,&ts->max_steps,NULL);CHKERRQ(ierr);
116   ierr = PetscOptionsReal("-ts_final_time","Time to run to","TSSetDuration",ts->max_time,&ts->max_time,NULL);CHKERRQ(ierr);
117   ierr = PetscOptionsReal("-ts_init_time","Initial time","TSSetTime",ts->ptime,&ts->ptime,NULL);CHKERRQ(ierr);
118   ierr = PetscOptionsReal("-ts_dt","Initial time step","TSSetTimeStep",ts->time_step,&time_step,&flg);CHKERRQ(ierr);
119   if (flg) {
120     ierr = TSSetTimeStep(ts,time_step);CHKERRQ(ierr);
121   }
122   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);
123   if (flg) {ierr = TSSetExactFinalTime(ts,eftopt);CHKERRQ(ierr);}
124   ierr = PetscOptionsInt("-ts_max_snes_failures","Maximum number of nonlinear solve failures","TSSetMaxSNESFailures",ts->max_snes_failures,&ts->max_snes_failures,NULL);CHKERRQ(ierr);
125   ierr = PetscOptionsInt("-ts_max_reject","Maximum number of step rejections before step fails","TSSetMaxStepRejections",ts->max_reject,&ts->max_reject,NULL);CHKERRQ(ierr);
126   ierr = PetscOptionsBool("-ts_error_if_step_fails","Error if no step succeeds","TSSetErrorIfStepFails",ts->errorifstepfailed,&ts->errorifstepfailed,NULL);CHKERRQ(ierr);
127   ierr = PetscOptionsReal("-ts_rtol","Relative tolerance for local truncation error","TSSetTolerances",ts->rtol,&ts->rtol,NULL);CHKERRQ(ierr);
128   ierr = PetscOptionsReal("-ts_atol","Absolute tolerance for local truncation error","TSSetTolerances",ts->atol,&ts->atol,NULL);CHKERRQ(ierr);
129 
130   /* Monitor options */
131   ierr = PetscOptionsString("-ts_monitor","Monitor timestep size","TSMonitorDefault","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
132   if (flg) {
133     ierr = PetscViewerASCIIOpen(PetscObjectComm((PetscObject)ts),monfilename,&monviewer);CHKERRQ(ierr);
134     ierr = TSMonitorSet(ts,TSMonitorDefault,monviewer,(PetscErrorCode (*)(void**))PetscViewerDestroy);CHKERRQ(ierr);
135   }
136   ierr = PetscOptionsString("-ts_monitor_python","Use Python function","TSMonitorSet",0,monfilename,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
137   if (flg) {ierr = PetscPythonMonitorSet((PetscObject)ts,monfilename);CHKERRQ(ierr);}
138 
139   ierr = PetscOptionsName("-ts_monitor_lg_timestep","Monitor timestep size graphically","TSMonitorLGTimeStep",&opt);CHKERRQ(ierr);
140   if (opt) {
141     TSMonitorLGCtx ctx;
142     PetscInt       howoften = 1;
143 
144     ierr = PetscOptionsInt("-ts_monitor_lg_timestep","Monitor timestep size graphically","TSMonitorLGTimeStep",howoften,&howoften,NULL);CHKERRQ(ierr);
145     ierr = TSMonitorLGCtxCreate(PetscObjectComm((PetscObject)ts),0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,howoften,&ctx);CHKERRQ(ierr);
146     ierr = TSMonitorSet(ts,TSMonitorLGTimeStep,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
147   }
148   ierr = PetscOptionsName("-ts_monitor_lg_solution","Monitor solution graphically","TSMonitorLGSolution",&opt);CHKERRQ(ierr);
149   if (opt) {
150     TSMonitorLGCtx ctx;
151     PetscInt       howoften = 1;
152 
153     ierr = PetscOptionsInt("-ts_monitor_lg_solution","Monitor solution graphically","TSMonitorLGSolution",howoften,&howoften,NULL);CHKERRQ(ierr);
154     ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);CHKERRQ(ierr);
155     ierr = TSMonitorSet(ts,TSMonitorLGSolution,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
156   }
157   ierr = PetscOptionsName("-ts_monitor_lg_error","Monitor error graphically","TSMonitorLGError",&opt);CHKERRQ(ierr);
158   if (opt) {
159     TSMonitorLGCtx ctx;
160     PetscInt       howoften = 1;
161 
162     ierr = PetscOptionsInt("-ts_monitor_lg_error","Monitor error graphically","TSMonitorLGError",howoften,&howoften,NULL);CHKERRQ(ierr);
163     ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);CHKERRQ(ierr);
164     ierr = TSMonitorSet(ts,TSMonitorLGError,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
165   }
166   ierr = PetscOptionsName("-ts_monitor_lg_snes_iterations","Monitor number nonlinear iterations for each timestep graphically","TSMonitorLGSNESIterations",&opt);CHKERRQ(ierr);
167   if (opt) {
168     TSMonitorLGCtx ctx;
169     PetscInt       howoften = 1;
170 
171     ierr = PetscOptionsInt("-ts_monitor_lg_snes_iterations","Monitor number nonlinear iterations for each timestep graphically","TSMonitorLGSNESIterations",howoften,&howoften,NULL);CHKERRQ(ierr);
172     ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,howoften,&ctx);CHKERRQ(ierr);
173     ierr = TSMonitorSet(ts,TSMonitorLGSNESIterations,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
174   }
175   ierr = PetscOptionsName("-ts_monitor_lg_ksp_iterations","Monitor number nonlinear iterations for each timestep graphically","TSMonitorLGKSPIterations",&opt);CHKERRQ(ierr);
176   if (opt) {
177     TSMonitorLGCtx ctx;
178     PetscInt       howoften = 1;
179 
180     ierr = PetscOptionsInt("-ts_monitor_lg_ksp_iterations","Monitor number nonlinear iterations for each timestep graphically","TSMonitorLGKSPIterations",howoften,&howoften,NULL);CHKERRQ(ierr);
181     ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,howoften,&ctx);CHKERRQ(ierr);
182     ierr = TSMonitorSet(ts,TSMonitorLGKSPIterations,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
183   }
184   ierr = PetscOptionsName("-ts_monitor_sp_eig","Monitor eigenvalues of linearized operator graphically","TSMonitorSPEig",&opt);CHKERRQ(ierr);
185   if (opt) {
186     TSMonitorSPEigCtx ctx;
187     PetscInt          howoften = 1;
188 
189     ierr = PetscOptionsInt("-ts_monitor_sp_eig","Monitor eigenvalues of linearized operator graphically","TSMonitorSPEig",howoften,&howoften,NULL);CHKERRQ(ierr);
190     ierr = TSMonitorSPEigCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);CHKERRQ(ierr);
191     ierr = TSMonitorSet(ts,TSMonitorSPEig,ctx,(PetscErrorCode (*)(void**))TSMonitorSPEigCtxDestroy);CHKERRQ(ierr);
192   }
193   opt  = PETSC_FALSE;
194   ierr = PetscOptionsName("-ts_monitor_draw_solution","Monitor solution graphically","TSMonitorDrawSolution",&opt);CHKERRQ(ierr);
195   if (opt) {
196     TSMonitorDrawCtx ctx;
197     PetscInt         howoften = 1;
198 
199     ierr = PetscOptionsInt("-ts_monitor_draw_solution","Monitor solution graphically","TSMonitorDrawSolution",howoften,&howoften,NULL);CHKERRQ(ierr);
200     ierr = TSMonitorDrawCtxCreate(PetscObjectComm((PetscObject)ts),0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);CHKERRQ(ierr);
201     ierr = TSMonitorSet(ts,TSMonitorDrawSolution,ctx,(PetscErrorCode (*)(void**))TSMonitorDrawCtxDestroy);CHKERRQ(ierr);
202   }
203   opt  = PETSC_FALSE;
204   ierr = PetscOptionsName("-ts_monitor_draw_solution_phase","Monitor solution graphically","TSMonitorDrawSolutionPhase",&opt);CHKERRQ(ierr);
205   if (opt) {
206     TSMonitorDrawCtx ctx;
207     PetscReal        bounds[4];
208     PetscInt         n = 4;
209     PetscDraw        draw;
210 
211     ierr = PetscOptionsRealArray("-ts_monitor_draw_solution_phase","Monitor solution graphically","TSMonitorDrawSolutionPhase",bounds,&n,NULL);CHKERRQ(ierr);
212     if (n != 4) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_ARG_WRONG,"Must provide bounding box of phase field");
213     ierr = TSMonitorDrawCtxCreate(PetscObjectComm((PetscObject)ts),0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,1,&ctx);CHKERRQ(ierr);
214     ierr = PetscViewerDrawGetDraw(ctx->viewer,0,&draw);CHKERRQ(ierr);
215     ierr = PetscDrawClear(draw);CHKERRQ(ierr);
216     ierr = PetscDrawAxisCreate(draw,&ctx->axis);CHKERRQ(ierr);
217     ierr = PetscDrawAxisSetLimits(ctx->axis,bounds[0],bounds[2],bounds[1],bounds[3]);CHKERRQ(ierr);
218     ierr = PetscDrawAxisSetLabels(ctx->axis,"Phase Diagram","Variable 1","Variable 2");CHKERRQ(ierr);
219     ierr = PetscDrawAxisDraw(ctx->axis);CHKERRQ(ierr);
220     /* ierr = PetscDrawSetCoordinates(draw,bounds[0],bounds[1],bounds[2],bounds[3]);CHKERRQ(ierr); */
221     ierr = TSMonitorSet(ts,TSMonitorDrawSolutionPhase,ctx,(PetscErrorCode (*)(void**))TSMonitorDrawCtxDestroy);CHKERRQ(ierr);
222   }
223   opt  = PETSC_FALSE;
224   ierr = PetscOptionsName("-ts_monitor_draw_error","Monitor error graphically","TSMonitorDrawError",&opt);CHKERRQ(ierr);
225   if (opt) {
226     TSMonitorDrawCtx ctx;
227     PetscInt         howoften = 1;
228 
229     ierr = PetscOptionsInt("-ts_monitor_draw_error","Monitor error graphically","TSMonitorDrawError",howoften,&howoften,NULL);CHKERRQ(ierr);
230     ierr = TSMonitorDrawCtxCreate(PetscObjectComm((PetscObject)ts),0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);CHKERRQ(ierr);
231     ierr = TSMonitorSet(ts,TSMonitorDrawError,ctx,(PetscErrorCode (*)(void**))TSMonitorDrawCtxDestroy);CHKERRQ(ierr);
232   }
233   opt  = PETSC_FALSE;
234   ierr = PetscOptionsString("-ts_monitor_solution_binary","Save each solution to a binary file","TSMonitorSolutionBinary",0,monfilename,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
235   if (flg) {
236     PetscViewer ctx;
237     if (monfilename[0]) {
238       ierr = PetscViewerBinaryOpen(PetscObjectComm((PetscObject)ts),monfilename,FILE_MODE_WRITE,&ctx);CHKERRQ(ierr);
239       ierr = TSMonitorSet(ts,TSMonitorSolutionBinary,ctx,(PetscErrorCode (*)(void**))PetscViewerDestroy);CHKERRQ(ierr);
240     } else {
241       ctx = PETSC_VIEWER_BINARY_(PetscObjectComm((PetscObject)ts));
242       ierr = TSMonitorSet(ts,TSMonitorSolutionBinary,ctx,(PetscErrorCode (*)(void**))NULL);CHKERRQ(ierr);
243     }
244   }
245   opt  = PETSC_FALSE;
246   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);
247   if (flg) {
248     const char *ptr,*ptr2;
249     char       *filetemplate;
250     if (!monfilename[0]) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"-ts_monitor_solution_vtk requires a file template, e.g. filename-%%03D.vts");
251     /* Do some cursory validation of the input. */
252     ierr = PetscStrstr(monfilename,"%",(char**)&ptr);CHKERRQ(ierr);
253     if (!ptr) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"-ts_monitor_solution_vtk requires a file template, e.g. filename-%%03D.vts");
254     for (ptr++; ptr && *ptr; ptr++) {
255       ierr = PetscStrchr("DdiouxX",*ptr,(char**)&ptr2);CHKERRQ(ierr);
256       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");
257       if (ptr2) break;
258     }
259     ierr = PetscStrallocpy(monfilename,&filetemplate);CHKERRQ(ierr);
260     ierr = TSMonitorSet(ts,TSMonitorSolutionVTK,filetemplate,(PetscErrorCode (*)(void**))TSMonitorSolutionVTKDestroy);CHKERRQ(ierr);
261   }
262 
263   ierr = PetscOptionsString("-ts_monitor_dmda_ray","Display a ray of the solution","None","y=0",dir,16,&flg);CHKERRQ(ierr);
264   if (flg) {
265     TSMonitorDMDARayCtx *rayctx;
266     int                 ray = 0;
267     DMDADirection       ddir;
268     DM                  da;
269     PetscMPIInt         rank;
270 
271     if (dir[1] != '=') SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_ARG_WRONG,"Unknown ray %s",dir);
272     if (dir[0] == 'x') ddir = DMDA_X;
273     else if (dir[0] == 'y') ddir = DMDA_Y;
274     else SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_ARG_WRONG,"Unknown ray %s",dir);
275     sscanf(dir+2,"%d",&ray);
276 
277     ierr = PetscInfo2(((PetscObject)ts),"Displaying DMDA ray %c = %D\n",dir[0],ray);CHKERRQ(ierr);
278     ierr = PetscNew(TSMonitorDMDARayCtx,&rayctx);CHKERRQ(ierr);
279     ierr = TSGetDM(ts,&da);CHKERRQ(ierr);
280     ierr = DMDAGetRay(da,ddir,ray,&rayctx->ray,&rayctx->scatter);CHKERRQ(ierr);
281     ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)ts),&rank);CHKERRQ(ierr);
282     if (!rank) {
283       ierr = PetscViewerDrawOpen(PETSC_COMM_SELF,0,0,0,0,600,300,&rayctx->viewer);CHKERRQ(ierr);
284     }
285     ierr = TSMonitorSet(ts,TSMonitorDMDARay,rayctx,TSMonitorDMDARayDestroy);CHKERRQ(ierr);
286   }
287 
288   ierr = TSGetAdapt(ts,&adapt);CHKERRQ(ierr);
289   ierr = TSAdaptSetFromOptions(adapt);CHKERRQ(ierr);
290 
291   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
292   if (ts->problem_type == TS_LINEAR) {ierr = SNESSetType(snes,SNESKSPONLY);CHKERRQ(ierr);}
293 
294   /* Handle specific TS options */
295   if (ts->ops->setfromoptions) {
296     ierr = (*ts->ops->setfromoptions)(ts);CHKERRQ(ierr);
297   }
298 
299   /* process any options handlers added with PetscObjectAddOptionsHandler() */
300   ierr = PetscObjectProcessOptionsHandlers((PetscObject)ts);CHKERRQ(ierr);
301   ierr = PetscOptionsEnd();CHKERRQ(ierr);
302   PetscFunctionReturn(0);
303 }
304 
305 #undef __FUNCT__
306 #undef __FUNCT__
307 #define __FUNCT__ "TSComputeRHSJacobian"
308 /*@
309    TSComputeRHSJacobian - Computes the Jacobian matrix that has been
310       set with TSSetRHSJacobian().
311 
312    Collective on TS and Vec
313 
314    Input Parameters:
315 +  ts - the TS context
316 .  t - current timestep
317 -  U - input vector
318 
319    Output Parameters:
320 +  A - Jacobian matrix
321 .  B - optional preconditioning matrix
322 -  flag - flag indicating matrix structure
323 
324    Notes:
325    Most users should not need to explicitly call this routine, as it
326    is used internally within the nonlinear solvers.
327 
328    See KSPSetOperators() for important information about setting the
329    flag parameter.
330 
331    Level: developer
332 
333 .keywords: SNES, compute, Jacobian, matrix
334 
335 .seealso:  TSSetRHSJacobian(), KSPSetOperators()
336 @*/
337 PetscErrorCode  TSComputeRHSJacobian(TS ts,PetscReal t,Vec U,Mat *A,Mat *B,MatStructure *flg)
338 {
339   PetscErrorCode ierr;
340   PetscInt       Ustate;
341   DM             dm;
342   DMTS           tsdm;
343   TSRHSJacobian  rhsjacobianfunc;
344   void           *ctx;
345   TSIJacobian    ijacobianfunc;
346 
347   PetscFunctionBegin;
348   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
349   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
350   PetscCheckSameComm(ts,1,U,3);
351   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
352   ierr = DMGetDMTS(dm,&tsdm);CHKERRQ(ierr);
353   ierr = DMTSGetRHSJacobian(dm,&rhsjacobianfunc,&ctx);CHKERRQ(ierr);
354   ierr = DMTSGetIJacobian(dm,&ijacobianfunc,NULL);CHKERRQ(ierr);
355   ierr = PetscObjectStateQuery((PetscObject)U,&Ustate);CHKERRQ(ierr);
356   if (ts->rhsjacobian.time == t && (ts->problem_type == TS_LINEAR || (ts->rhsjacobian.X == U && ts->rhsjacobian.Xstate == Ustate))) {
357     *flg = ts->rhsjacobian.mstructure;
358     PetscFunctionReturn(0);
359   }
360 
361   if (!rhsjacobianfunc && !ijacobianfunc) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"Must call TSSetRHSJacobian() and / or TSSetIJacobian()");
362 
363   if (ts->rhsjacobian.reuse) {
364     ierr = MatShift(*A,-ts->rhsjacobian.shift);CHKERRQ(ierr);
365     ierr = MatScale(*A,1./ts->rhsjacobian.scale);CHKERRQ(ierr);
366     if (*A != *B) {
367       ierr = MatShift(*B,-ts->rhsjacobian.shift);CHKERRQ(ierr);
368       ierr = MatScale(*B,1./ts->rhsjacobian.scale);CHKERRQ(ierr);
369     }
370     ts->rhsjacobian.shift = 0;
371     ts->rhsjacobian.scale = 1.;
372   }
373 
374   if (rhsjacobianfunc) {
375     ierr = PetscLogEventBegin(TS_JacobianEval,ts,U,*A,*B);CHKERRQ(ierr);
376     *flg = DIFFERENT_NONZERO_PATTERN;
377     PetscStackPush("TS user Jacobian function");
378     ierr = (*rhsjacobianfunc)(ts,t,U,A,B,flg,ctx);CHKERRQ(ierr);
379     PetscStackPop;
380     ierr = PetscLogEventEnd(TS_JacobianEval,ts,U,*A,*B);CHKERRQ(ierr);
381     /* make sure user returned a correct Jacobian and preconditioner */
382     PetscValidHeaderSpecific(*A,MAT_CLASSID,4);
383     PetscValidHeaderSpecific(*B,MAT_CLASSID,5);
384   } else {
385     ierr = MatZeroEntries(*A);CHKERRQ(ierr);
386     if (*A != *B) {ierr = MatZeroEntries(*B);CHKERRQ(ierr);}
387     *flg = SAME_NONZERO_PATTERN;
388   }
389   ts->rhsjacobian.time       = t;
390   ts->rhsjacobian.X          = U;
391   ierr                       = PetscObjectStateQuery((PetscObject)U,&ts->rhsjacobian.Xstate);CHKERRQ(ierr);
392   ts->rhsjacobian.mstructure = *flg;
393   PetscFunctionReturn(0);
394 }
395 
396 #undef __FUNCT__
397 #define __FUNCT__ "TSComputeRHSFunction"
398 /*@
399    TSComputeRHSFunction - Evaluates the right-hand-side function.
400 
401    Collective on TS and Vec
402 
403    Input Parameters:
404 +  ts - the TS context
405 .  t - current time
406 -  U - state vector
407 
408    Output Parameter:
409 .  y - right hand side
410 
411    Note:
412    Most users should not need to explicitly call this routine, as it
413    is used internally within the nonlinear solvers.
414 
415    Level: developer
416 
417 .keywords: TS, compute
418 
419 .seealso: TSSetRHSFunction(), TSComputeIFunction()
420 @*/
421 PetscErrorCode TSComputeRHSFunction(TS ts,PetscReal t,Vec U,Vec y)
422 {
423   PetscErrorCode ierr;
424   TSRHSFunction  rhsfunction;
425   TSIFunction    ifunction;
426   void           *ctx;
427   DM             dm;
428 
429   PetscFunctionBegin;
430   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
431   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
432   PetscValidHeaderSpecific(y,VEC_CLASSID,4);
433   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
434   ierr = DMTSGetRHSFunction(dm,&rhsfunction,&ctx);CHKERRQ(ierr);
435   ierr = DMTSGetIFunction(dm,&ifunction,NULL);CHKERRQ(ierr);
436 
437   if (!rhsfunction && !ifunction) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"Must call TSSetRHSFunction() and / or TSSetIFunction()");
438 
439   ierr = PetscLogEventBegin(TS_FunctionEval,ts,U,y,0);CHKERRQ(ierr);
440   if (rhsfunction) {
441     PetscStackPush("TS user right-hand-side function");
442     ierr = (*rhsfunction)(ts,t,U,y,ctx);CHKERRQ(ierr);
443     PetscStackPop;
444   } else {
445     ierr = VecZeroEntries(y);CHKERRQ(ierr);
446   }
447 
448   ierr = PetscLogEventEnd(TS_FunctionEval,ts,U,y,0);CHKERRQ(ierr);
449   PetscFunctionReturn(0);
450 }
451 
452 #undef __FUNCT__
453 #define __FUNCT__ "TSComputeSolutionFunction"
454 /*@
455    TSComputeSolutionFunction - Evaluates the solution function.
456 
457    Collective on TS and Vec
458 
459    Input Parameters:
460 +  ts - the TS context
461 -  t - current time
462 
463    Output Parameter:
464 .  U - the solution
465 
466    Note:
467    Most users should not need to explicitly call this routine, as it
468    is used internally within the nonlinear solvers.
469 
470    Level: developer
471 
472 .keywords: TS, compute
473 
474 .seealso: TSSetSolutionFunction(), TSSetRHSFunction(), TSComputeIFunction()
475 @*/
476 PetscErrorCode TSComputeSolutionFunction(TS ts,PetscReal t,Vec U)
477 {
478   PetscErrorCode     ierr;
479   TSSolutionFunction solutionfunction;
480   void               *ctx;
481   DM                 dm;
482 
483   PetscFunctionBegin;
484   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
485   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
486   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
487   ierr = DMTSGetSolutionFunction(dm,&solutionfunction,&ctx);CHKERRQ(ierr);
488 
489   if (solutionfunction) {
490     PetscStackPush("TS user solution function");
491     ierr = (*solutionfunction)(ts,t,U,ctx);CHKERRQ(ierr);
492     PetscStackPop;
493   }
494   PetscFunctionReturn(0);
495 }
496 #undef __FUNCT__
497 #define __FUNCT__ "TSComputeForcingFunction"
498 /*@
499    TSComputeForcingFunction - Evaluates the forcing function.
500 
501    Collective on TS and Vec
502 
503    Input Parameters:
504 +  ts - the TS context
505 -  t - current time
506 
507    Output Parameter:
508 .  U - the function value
509 
510    Note:
511    Most users should not need to explicitly call this routine, as it
512    is used internally within the nonlinear solvers.
513 
514    Level: developer
515 
516 .keywords: TS, compute
517 
518 .seealso: TSSetSolutionFunction(), TSSetRHSFunction(), TSComputeIFunction()
519 @*/
520 PetscErrorCode TSComputeForcingFunction(TS ts,PetscReal t,Vec U)
521 {
522   PetscErrorCode     ierr, (*forcing)(TS,PetscReal,Vec,void*);
523   void               *ctx;
524   DM                 dm;
525 
526   PetscFunctionBegin;
527   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
528   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
529   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
530   ierr = DMTSGetForcingFunction(dm,&forcing,&ctx);CHKERRQ(ierr);
531 
532   if (forcing) {
533     PetscStackPush("TS user forcing function");
534     ierr = (*forcing)(ts,t,U,ctx);CHKERRQ(ierr);
535     PetscStackPop;
536   }
537   PetscFunctionReturn(0);
538 }
539 
540 #undef __FUNCT__
541 #define __FUNCT__ "TSGetRHSVec_Private"
542 static PetscErrorCode TSGetRHSVec_Private(TS ts,Vec *Frhs)
543 {
544   Vec            F;
545   PetscErrorCode ierr;
546 
547   PetscFunctionBegin;
548   *Frhs = NULL;
549   ierr  = TSGetIFunction(ts,&F,NULL,NULL);CHKERRQ(ierr);
550   if (!ts->Frhs) {
551     ierr = VecDuplicate(F,&ts->Frhs);CHKERRQ(ierr);
552   }
553   *Frhs = ts->Frhs;
554   PetscFunctionReturn(0);
555 }
556 
557 #undef __FUNCT__
558 #define __FUNCT__ "TSGetRHSMats_Private"
559 static PetscErrorCode TSGetRHSMats_Private(TS ts,Mat *Arhs,Mat *Brhs)
560 {
561   Mat            A,B;
562   PetscErrorCode ierr;
563 
564   PetscFunctionBegin;
565   ierr = TSGetIJacobian(ts,&A,&B,NULL,NULL);CHKERRQ(ierr);
566   if (Arhs) {
567     if (!ts->Arhs) {
568       ierr = MatDuplicate(A,MAT_DO_NOT_COPY_VALUES,&ts->Arhs);CHKERRQ(ierr);
569     }
570     *Arhs = ts->Arhs;
571   }
572   if (Brhs) {
573     if (!ts->Brhs) {
574       ierr = MatDuplicate(B,MAT_DO_NOT_COPY_VALUES,&ts->Brhs);CHKERRQ(ierr);
575     }
576     *Brhs = ts->Brhs;
577   }
578   PetscFunctionReturn(0);
579 }
580 
581 #undef __FUNCT__
582 #define __FUNCT__ "TSComputeIFunction"
583 /*@
584    TSComputeIFunction - Evaluates the DAE residual written in implicit form F(t,U,Udot)=0
585 
586    Collective on TS and Vec
587 
588    Input Parameters:
589 +  ts - the TS context
590 .  t - current time
591 .  U - state vector
592 .  Udot - time derivative of state vector
593 -  imex - flag indicates if the method is IMEX so that the RHSFunction should be kept separate
594 
595    Output Parameter:
596 .  Y - right hand side
597 
598    Note:
599    Most users should not need to explicitly call this routine, as it
600    is used internally within the nonlinear solvers.
601 
602    If the user did did not write their equations in implicit form, this
603    function recasts them in implicit form.
604 
605    Level: developer
606 
607 .keywords: TS, compute
608 
609 .seealso: TSSetIFunction(), TSComputeRHSFunction()
610 @*/
611 PetscErrorCode TSComputeIFunction(TS ts,PetscReal t,Vec U,Vec Udot,Vec Y,PetscBool imex)
612 {
613   PetscErrorCode ierr;
614   TSIFunction    ifunction;
615   TSRHSFunction  rhsfunction;
616   void           *ctx;
617   DM             dm;
618 
619   PetscFunctionBegin;
620   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
621   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
622   PetscValidHeaderSpecific(Udot,VEC_CLASSID,4);
623   PetscValidHeaderSpecific(Y,VEC_CLASSID,5);
624 
625   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
626   ierr = DMTSGetIFunction(dm,&ifunction,&ctx);CHKERRQ(ierr);
627   ierr = DMTSGetRHSFunction(dm,&rhsfunction,NULL);CHKERRQ(ierr);
628 
629   if (!rhsfunction && !ifunction) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"Must call TSSetRHSFunction() and / or TSSetIFunction()");
630 
631   ierr = PetscLogEventBegin(TS_FunctionEval,ts,U,Udot,Y);CHKERRQ(ierr);
632   if (ifunction) {
633     PetscStackPush("TS user implicit function");
634     ierr = (*ifunction)(ts,t,U,Udot,Y,ctx);CHKERRQ(ierr);
635     PetscStackPop;
636   }
637   if (imex) {
638     if (!ifunction) {
639       ierr = VecCopy(Udot,Y);CHKERRQ(ierr);
640     }
641   } else if (rhsfunction) {
642     if (ifunction) {
643       Vec Frhs;
644       ierr = TSGetRHSVec_Private(ts,&Frhs);CHKERRQ(ierr);
645       ierr = TSComputeRHSFunction(ts,t,U,Frhs);CHKERRQ(ierr);
646       ierr = VecAXPY(Y,-1,Frhs);CHKERRQ(ierr);
647     } else {
648       ierr = TSComputeRHSFunction(ts,t,U,Y);CHKERRQ(ierr);
649       ierr = VecAYPX(Y,-1,Udot);CHKERRQ(ierr);
650     }
651   }
652   ierr = PetscLogEventEnd(TS_FunctionEval,ts,U,Udot,Y);CHKERRQ(ierr);
653   PetscFunctionReturn(0);
654 }
655 
656 #undef __FUNCT__
657 #define __FUNCT__ "TSComputeIJacobian"
658 /*@
659    TSComputeIJacobian - Evaluates the Jacobian of the DAE
660 
661    Collective on TS and Vec
662 
663    Input
664       Input Parameters:
665 +  ts - the TS context
666 .  t - current timestep
667 .  U - state vector
668 .  Udot - time derivative of state vector
669 .  shift - shift to apply, see note below
670 -  imex - flag indicates if the method is IMEX so that the RHSJacobian should be kept separate
671 
672    Output Parameters:
673 +  A - Jacobian matrix
674 .  B - optional preconditioning matrix
675 -  flag - flag indicating matrix structure
676 
677    Notes:
678    If F(t,U,Udot)=0 is the DAE, the required Jacobian is
679 
680    dF/dU + shift*dF/dUdot
681 
682    Most users should not need to explicitly call this routine, as it
683    is used internally within the nonlinear solvers.
684 
685    Level: developer
686 
687 .keywords: TS, compute, Jacobian, matrix
688 
689 .seealso:  TSSetIJacobian()
690 @*/
691 PetscErrorCode TSComputeIJacobian(TS ts,PetscReal t,Vec U,Vec Udot,PetscReal shift,Mat *A,Mat *B,MatStructure *flg,PetscBool imex)
692 {
693   PetscErrorCode ierr;
694   TSIJacobian    ijacobian;
695   TSRHSJacobian  rhsjacobian;
696   DM             dm;
697   void           *ctx;
698 
699   PetscFunctionBegin;
700   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
701   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
702   PetscValidHeaderSpecific(Udot,VEC_CLASSID,4);
703   PetscValidPointer(A,6);
704   PetscValidHeaderSpecific(*A,MAT_CLASSID,6);
705   PetscValidPointer(B,7);
706   PetscValidHeaderSpecific(*B,MAT_CLASSID,7);
707   PetscValidPointer(flg,8);
708 
709   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
710   ierr = DMTSGetIJacobian(dm,&ijacobian,&ctx);CHKERRQ(ierr);
711   ierr = DMTSGetRHSJacobian(dm,&rhsjacobian,NULL);CHKERRQ(ierr);
712 
713   if (!rhsjacobian && !ijacobian) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_USER,"Must call TSSetRHSJacobian() and / or TSSetIJacobian()");
714 
715   *flg = SAME_NONZERO_PATTERN;  /* In case we're solving a linear problem in which case it wouldn't get initialized below. */
716   ierr = PetscLogEventBegin(TS_JacobianEval,ts,U,*A,*B);CHKERRQ(ierr);
717   if (ijacobian) {
718     *flg = DIFFERENT_NONZERO_PATTERN;
719     PetscStackPush("TS user implicit Jacobian");
720     ierr = (*ijacobian)(ts,t,U,Udot,shift,A,B,flg,ctx);CHKERRQ(ierr);
721     PetscStackPop;
722     /* make sure user returned a correct Jacobian and preconditioner */
723     PetscValidHeaderSpecific(*A,MAT_CLASSID,4);
724     PetscValidHeaderSpecific(*B,MAT_CLASSID,5);
725   }
726   if (imex) {
727     if (!ijacobian) {  /* system was written as Udot = G(t,U) */
728       ierr = MatZeroEntries(*A);CHKERRQ(ierr);
729       ierr = MatShift(*A,shift);CHKERRQ(ierr);
730       if (*A != *B) {
731         ierr = MatZeroEntries(*B);CHKERRQ(ierr);
732         ierr = MatShift(*B,shift);CHKERRQ(ierr);
733       }
734       *flg = SAME_PRECONDITIONER;
735     }
736   } else {
737     Mat Arhs = NULL,Brhs = NULL;
738     MatStructure flg2;
739     if (rhsjacobian) {
740       ierr = TSGetRHSMats_Private(ts,&Arhs,&Brhs);CHKERRQ(ierr);
741       ierr = TSComputeRHSJacobian(ts,t,U,&Arhs,&Brhs,&flg2);CHKERRQ(ierr);
742     }
743     if (Arhs == *A) {           /* No IJacobian, so we only have the RHS matrix */
744       ts->rhsjacobian.scale = -1;
745       ts->rhsjacobian.shift = shift;
746       ierr = MatScale(*A,-1);CHKERRQ(ierr);
747       ierr = MatShift(*A,shift);CHKERRQ(ierr);
748       if (*A != *B) {
749         ierr = MatScale(*B,-1);CHKERRQ(ierr);
750         ierr = MatShift(*B,shift);CHKERRQ(ierr);
751       }
752     } else if (Arhs) {          /* Both IJacobian and RHSJacobian */
753       MatStructure axpy = DIFFERENT_NONZERO_PATTERN;
754       if (!ijacobian) {         /* No IJacobian provided, but we have a separate RHS matrix */
755         ierr = MatZeroEntries(*A);CHKERRQ(ierr);
756         ierr = MatShift(*A,shift);CHKERRQ(ierr);
757         if (*A != *B) {
758           ierr = MatZeroEntries(*B);CHKERRQ(ierr);
759           ierr = MatShift(*B,shift);CHKERRQ(ierr);
760         }
761       }
762       ierr = MatAXPY(*A,-1,Arhs,axpy);CHKERRQ(ierr);
763       if (*A != *B) {
764         ierr = MatAXPY(*B,-1,Brhs,axpy);CHKERRQ(ierr);
765       }
766       *flg = PetscMin(*flg,flg2);
767     }
768   }
769 
770   ierr = PetscLogEventEnd(TS_JacobianEval,ts,U,*A,*B);CHKERRQ(ierr);
771   PetscFunctionReturn(0);
772 }
773 
774 #undef __FUNCT__
775 #define __FUNCT__ "TSSetRHSFunction"
776 /*@C
777     TSSetRHSFunction - Sets the routine for evaluating the function,
778     where U_t = G(t,u).
779 
780     Logically Collective on TS
781 
782     Input Parameters:
783 +   ts - the TS context obtained from TSCreate()
784 .   r - vector to put the computed right hand side (or NULL to have it created)
785 .   f - routine for evaluating the right-hand-side function
786 -   ctx - [optional] user-defined context for private data for the
787           function evaluation routine (may be NULL)
788 
789     Calling sequence of func:
790 $     func (TS ts,PetscReal t,Vec u,Vec F,void *ctx);
791 
792 +   t - current timestep
793 .   u - input vector
794 .   F - function vector
795 -   ctx - [optional] user-defined function context
796 
797     Level: beginner
798 
799 .keywords: TS, timestep, set, right-hand-side, function
800 
801 .seealso: TSSetRHSJacobian(), TSSetIJacobian()
802 @*/
803 PetscErrorCode  TSSetRHSFunction(TS ts,Vec r,PetscErrorCode (*f)(TS,PetscReal,Vec,Vec,void*),void *ctx)
804 {
805   PetscErrorCode ierr;
806   SNES           snes;
807   Vec            ralloc = NULL;
808   DM             dm;
809 
810   PetscFunctionBegin;
811   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
812   if (r) PetscValidHeaderSpecific(r,VEC_CLASSID,2);
813 
814   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
815   ierr = DMTSSetRHSFunction(dm,f,ctx);CHKERRQ(ierr);
816   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
817   if (!r && !ts->dm && ts->vec_sol) {
818     ierr = VecDuplicate(ts->vec_sol,&ralloc);CHKERRQ(ierr);
819     r    = ralloc;
820   }
821   ierr = SNESSetFunction(snes,r,SNESTSFormFunction,ts);CHKERRQ(ierr);
822   ierr = VecDestroy(&ralloc);CHKERRQ(ierr);
823   PetscFunctionReturn(0);
824 }
825 
826 #undef __FUNCT__
827 #define __FUNCT__ "TSSetSolutionFunction"
828 /*@C
829     TSSetSolutionFunction - Provide a function that computes the solution of the ODE or DAE
830 
831     Logically Collective on TS
832 
833     Input Parameters:
834 +   ts - the TS context obtained from TSCreate()
835 .   f - routine for evaluating the solution
836 -   ctx - [optional] user-defined context for private data for the
837           function evaluation routine (may be NULL)
838 
839     Calling sequence of func:
840 $     func (TS ts,PetscReal t,Vec u,void *ctx);
841 
842 +   t - current timestep
843 .   u - output vector
844 -   ctx - [optional] user-defined function context
845 
846     Notes:
847     This routine is used for testing accuracy of time integration schemes when you already know the solution.
848     If analytic solutions are not known for your system, consider using the Method of Manufactured Solutions to
849     create closed-form solutions with non-physical forcing terms.
850 
851     For low-dimensional problems solved in serial, such as small discrete systems, TSMonitorLGError() can be used to monitor the error history.
852 
853     Level: beginner
854 
855 .keywords: TS, timestep, set, right-hand-side, function
856 
857 .seealso: TSSetRHSJacobian(), TSSetIJacobian(), TSComputeSolutionFunction(), TSSetForcingFunction()
858 @*/
859 PetscErrorCode  TSSetSolutionFunction(TS ts,PetscErrorCode (*f)(TS,PetscReal,Vec,void*),void *ctx)
860 {
861   PetscErrorCode ierr;
862   DM             dm;
863 
864   PetscFunctionBegin;
865   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
866   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
867   ierr = DMTSSetSolutionFunction(dm,f,ctx);CHKERRQ(ierr);
868   PetscFunctionReturn(0);
869 }
870 
871 #undef __FUNCT__
872 #define __FUNCT__ "TSSetForcingFunction"
873 /*@C
874     TSSetForcingFunction - Provide a function that computes a forcing term for a ODE or PDE
875 
876     Logically Collective on TS
877 
878     Input Parameters:
879 +   ts - the TS context obtained from TSCreate()
880 .   f - routine for evaluating the forcing function
881 -   ctx - [optional] user-defined context for private data for the
882           function evaluation routine (may be NULL)
883 
884     Calling sequence of func:
885 $     func (TS ts,PetscReal t,Vec u,void *ctx);
886 
887 +   t - current timestep
888 .   u - output vector
889 -   ctx - [optional] user-defined function context
890 
891     Notes:
892     This routine is useful for testing accuracy of time integration schemes when using the Method of Manufactured Solutions to
893     create closed-form solutions with a non-physical forcing term.
894 
895     For low-dimensional problems solved in serial, such as small discrete systems, TSMonitorLGError() can be used to monitor the error history.
896 
897     Level: beginner
898 
899 .keywords: TS, timestep, set, right-hand-side, function
900 
901 .seealso: TSSetRHSJacobian(), TSSetIJacobian(), TSComputeSolutionFunction(), TSSetSolutionFunction()
902 @*/
903 PetscErrorCode  TSSetForcingFunction(TS ts,PetscErrorCode (*f)(TS,PetscReal,Vec,void*),void *ctx)
904 {
905   PetscErrorCode ierr;
906   DM             dm;
907 
908   PetscFunctionBegin;
909   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
910   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
911   ierr = DMTSSetForcingFunction(dm,f,ctx);CHKERRQ(ierr);
912   PetscFunctionReturn(0);
913 }
914 
915 #undef __FUNCT__
916 #define __FUNCT__ "TSSetRHSJacobian"
917 /*@C
918    TSSetRHSJacobian - Sets the function to compute the Jacobian of F,
919    where U_t = G(U,t), as well as the location to store the matrix.
920 
921    Logically Collective on TS
922 
923    Input Parameters:
924 +  ts  - the TS context obtained from TSCreate()
925 .  Amat - (approximate) Jacobian matrix
926 .  Pmat - matrix from which preconditioner is to be constructed (usually the same as Amat)
927 .  f   - the Jacobian evaluation routine
928 -  ctx - [optional] user-defined context for private data for the
929          Jacobian evaluation routine (may be NULL)
930 
931    Calling sequence of func:
932 $     func (TS ts,PetscReal t,Vec u,Mat *A,Mat *B,MatStructure *flag,void *ctx);
933 
934 +  t - current timestep
935 .  u - input vector
936 .  Amat - (approximate) Jacobian matrix
937 .  Pmat - matrix from which preconditioner is to be constructed (usually the same as Amat)
938 .  flag - flag indicating information about the preconditioner matrix
939           structure (same as flag in KSPSetOperators())
940 -  ctx - [optional] user-defined context for matrix evaluation routine
941 
942    Notes:
943    See KSPSetOperators() for important information about setting the flag
944    output parameter in the routine func().  Be sure to read this information!
945 
946    The routine func() takes Mat * as the matrix arguments rather than Mat.
947    This allows the matrix evaluation routine to replace A and/or B with a
948    completely new matrix structure (not just different matrix elements)
949    when appropriate, for instance, if the nonzero structure is changing
950    throughout the global iterations.
951 
952    Level: beginner
953 
954 .keywords: TS, timestep, set, right-hand-side, Jacobian
955 
956 .seealso: SNESComputeJacobianDefaultColor(), TSSetRHSFunction(), TSRHSJacobianSetReuse()
957 
958 @*/
959 PetscErrorCode  TSSetRHSJacobian(TS ts,Mat Amat,Mat Pmat,TSRHSJacobian f,void *ctx)
960 {
961   PetscErrorCode ierr;
962   SNES           snes;
963   DM             dm;
964   TSIJacobian    ijacobian;
965 
966   PetscFunctionBegin;
967   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
968   if (Amat) PetscValidHeaderSpecific(Amat,MAT_CLASSID,2);
969   if (Pmat) PetscValidHeaderSpecific(Pmat,MAT_CLASSID,3);
970   if (Amat) PetscCheckSameComm(ts,1,Amat,2);
971   if (Pmat) PetscCheckSameComm(ts,1,Pmat,3);
972 
973   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
974   ierr = DMTSSetRHSJacobian(dm,f,ctx);CHKERRQ(ierr);
975   if (f == TSComputeRHSJacobianConstant) {
976     /* Handle this case automatically for the user; otherwise user should call themselves. */
977     ierr = TSRHSJacobianSetReuse(ts,PETSC_TRUE);CHKERRQ(ierr);
978   }
979   ierr = DMTSGetIJacobian(dm,&ijacobian,NULL);CHKERRQ(ierr);
980   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
981   if (!ijacobian) {
982     ierr = SNESSetJacobian(snes,Amat,Pmat,SNESTSFormJacobian,ts);CHKERRQ(ierr);
983   }
984   if (Amat) {
985     ierr = PetscObjectReference((PetscObject)Amat);CHKERRQ(ierr);
986     ierr = MatDestroy(&ts->Arhs);CHKERRQ(ierr);
987 
988     ts->Arhs = Amat;
989   }
990   if (Pmat) {
991     ierr = PetscObjectReference((PetscObject)Pmat);CHKERRQ(ierr);
992     ierr = MatDestroy(&ts->Brhs);CHKERRQ(ierr);
993 
994     ts->Brhs = Pmat;
995   }
996   PetscFunctionReturn(0);
997 }
998 
999 
1000 #undef __FUNCT__
1001 #define __FUNCT__ "TSSetIFunction"
1002 /*@C
1003    TSSetIFunction - Set the function to compute F(t,U,U_t) where F() = 0 is the DAE to be solved.
1004 
1005    Logically Collective on TS
1006 
1007    Input Parameters:
1008 +  ts  - the TS context obtained from TSCreate()
1009 .  r   - vector to hold the residual (or NULL to have it created internally)
1010 .  f   - the function evaluation routine
1011 -  ctx - user-defined context for private data for the function evaluation routine (may be NULL)
1012 
1013    Calling sequence of f:
1014 $  f(TS ts,PetscReal t,Vec u,Vec u_t,Vec F,ctx);
1015 
1016 +  t   - time at step/stage being solved
1017 .  u   - state vector
1018 .  u_t - time derivative of state vector
1019 .  F   - function vector
1020 -  ctx - [optional] user-defined context for matrix evaluation routine
1021 
1022    Important:
1023    The user MUST call either this routine, TSSetRHSFunction().  This routine must be used when not solving an ODE, for example a DAE.
1024 
1025    Level: beginner
1026 
1027 .keywords: TS, timestep, set, DAE, Jacobian
1028 
1029 .seealso: TSSetRHSJacobian(), TSSetRHSFunction(), TSSetIJacobian()
1030 @*/
1031 PetscErrorCode  TSSetIFunction(TS ts,Vec res,TSIFunction f,void *ctx)
1032 {
1033   PetscErrorCode ierr;
1034   SNES           snes;
1035   Vec            resalloc = NULL;
1036   DM             dm;
1037 
1038   PetscFunctionBegin;
1039   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1040   if (res) PetscValidHeaderSpecific(res,VEC_CLASSID,2);
1041 
1042   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1043   ierr = DMTSSetIFunction(dm,f,ctx);CHKERRQ(ierr);
1044 
1045   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1046   if (!res && !ts->dm && ts->vec_sol) {
1047     ierr = VecDuplicate(ts->vec_sol,&resalloc);CHKERRQ(ierr);
1048     res  = resalloc;
1049   }
1050   ierr = SNESSetFunction(snes,res,SNESTSFormFunction,ts);CHKERRQ(ierr);
1051   ierr = VecDestroy(&resalloc);CHKERRQ(ierr);
1052   PetscFunctionReturn(0);
1053 }
1054 
1055 #undef __FUNCT__
1056 #define __FUNCT__ "TSGetIFunction"
1057 /*@C
1058    TSGetIFunction - Returns the vector where the implicit residual is stored and the function/contex to compute it.
1059 
1060    Not Collective
1061 
1062    Input Parameter:
1063 .  ts - the TS context
1064 
1065    Output Parameter:
1066 +  r - vector to hold residual (or NULL)
1067 .  func - the function to compute residual (or NULL)
1068 -  ctx - the function context (or NULL)
1069 
1070    Level: advanced
1071 
1072 .keywords: TS, nonlinear, get, function
1073 
1074 .seealso: TSSetIFunction(), SNESGetFunction()
1075 @*/
1076 PetscErrorCode TSGetIFunction(TS ts,Vec *r,TSIFunction *func,void **ctx)
1077 {
1078   PetscErrorCode ierr;
1079   SNES           snes;
1080   DM             dm;
1081 
1082   PetscFunctionBegin;
1083   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1084   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1085   ierr = SNESGetFunction(snes,r,NULL,NULL);CHKERRQ(ierr);
1086   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1087   ierr = DMTSGetIFunction(dm,func,ctx);CHKERRQ(ierr);
1088   PetscFunctionReturn(0);
1089 }
1090 
1091 #undef __FUNCT__
1092 #define __FUNCT__ "TSGetRHSFunction"
1093 /*@C
1094    TSGetRHSFunction - Returns the vector where the right hand side is stored and the function/context to compute it.
1095 
1096    Not Collective
1097 
1098    Input Parameter:
1099 .  ts - the TS context
1100 
1101    Output Parameter:
1102 +  r - vector to hold computed right hand side (or NULL)
1103 .  func - the function to compute right hand side (or NULL)
1104 -  ctx - the function context (or NULL)
1105 
1106    Level: advanced
1107 
1108 .keywords: TS, nonlinear, get, function
1109 
1110 .seealso: TSSetRhsfunction(), SNESGetFunction()
1111 @*/
1112 PetscErrorCode TSGetRHSFunction(TS ts,Vec *r,TSRHSFunction *func,void **ctx)
1113 {
1114   PetscErrorCode ierr;
1115   SNES           snes;
1116   DM             dm;
1117 
1118   PetscFunctionBegin;
1119   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1120   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1121   ierr = SNESGetFunction(snes,r,NULL,NULL);CHKERRQ(ierr);
1122   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1123   ierr = DMTSGetRHSFunction(dm,func,ctx);CHKERRQ(ierr);
1124   PetscFunctionReturn(0);
1125 }
1126 
1127 #undef __FUNCT__
1128 #define __FUNCT__ "TSSetIJacobian"
1129 /*@C
1130    TSSetIJacobian - Set the function to compute the matrix dF/dU + a*dF/dU_t where F(t,U,U_t) is the function
1131         you provided with TSSetIFunction().
1132 
1133    Logically Collective on TS
1134 
1135    Input Parameters:
1136 +  ts  - the TS context obtained from TSCreate()
1137 .  Amat - (approximate) Jacobian matrix
1138 .  Pmat - matrix used to compute preconditioner (usually the same as Amat)
1139 .  f   - the Jacobian evaluation routine
1140 -  ctx - user-defined context for private data for the Jacobian evaluation routine (may be NULL)
1141 
1142    Calling sequence of f:
1143 $  f(TS ts,PetscReal t,Vec U,Vec U_t,PetscReal a,Mat *Amat,Mat *Pmat,MatStructure *flag,void *ctx);
1144 
1145 +  t    - time at step/stage being solved
1146 .  U    - state vector
1147 .  U_t  - time derivative of state vector
1148 .  a    - shift
1149 .  Amat - (approximate) Jacobian of F(t,U,W+a*U), equivalent to dF/dU + a*dF/dU_t
1150 .  Pmat - matrix used for constructing preconditioner, usually the same as Amat
1151 .  flag - flag indicating information about the preconditioner matrix
1152           structure (same as flag in KSPSetOperators())
1153 -  ctx  - [optional] user-defined context for matrix evaluation routine
1154 
1155    Notes:
1156    The matrices Amat and Pmat are exactly the matrices that are used by SNES for the nonlinear solve.
1157 
1158    The matrix dF/dU + a*dF/dU_t you provide turns out to be
1159    the Jacobian of F(t,U,W+a*U) where F(t,U,U_t) = 0 is the DAE to be solved.
1160    The time integrator internally approximates U_t by W+a*U where the positive "shift"
1161    a and vector W depend on the integration method, step size, and past states. For example with
1162    the backward Euler method a = 1/dt and W = -a*U(previous timestep) so
1163    W + a*U = a*(U - U(previous timestep)) = (U - U(previous timestep))/dt
1164 
1165    Level: beginner
1166 
1167 .keywords: TS, timestep, DAE, Jacobian
1168 
1169 .seealso: TSSetIFunction(), TSSetRHSJacobian(), SNESComputeJacobianDefaultColor(), SNESComputeJacobianDefault()
1170 
1171 @*/
1172 PetscErrorCode  TSSetIJacobian(TS ts,Mat Amat,Mat Pmat,TSIJacobian f,void *ctx)
1173 {
1174   PetscErrorCode ierr;
1175   SNES           snes;
1176   DM             dm;
1177 
1178   PetscFunctionBegin;
1179   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1180   if (Amat) PetscValidHeaderSpecific(Amat,MAT_CLASSID,2);
1181   if (Pmat) PetscValidHeaderSpecific(Pmat,MAT_CLASSID,3);
1182   if (Amat) PetscCheckSameComm(ts,1,Amat,2);
1183   if (Pmat) PetscCheckSameComm(ts,1,Pmat,3);
1184 
1185   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1186   ierr = DMTSSetIJacobian(dm,f,ctx);CHKERRQ(ierr);
1187 
1188   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1189   ierr = SNESSetJacobian(snes,Amat,Pmat,SNESTSFormJacobian,ts);CHKERRQ(ierr);
1190   PetscFunctionReturn(0);
1191 }
1192 
1193 #undef __FUNCT__
1194 #define __FUNCT__ "TSRHSJacobianSetReuse"
1195 /*@
1196    TSRHSJacobianSetReuse - restore RHS Jacobian before re-evaluating.  Without this flag, TS will change the sign and
1197    shift the RHS Jacobian for a finite-time-step implicit solve, in which case the user function will need to recompute
1198    the entire Jacobian.  The reuse flag must be set if the evaluation function will assume that the matrix entries have
1199    not been changed by the TS.
1200 
1201    Logically Collective
1202 
1203    Input Arguments:
1204 +  ts - TS context obtained from TSCreate()
1205 -  reuse - PETSC_TRUE if the RHS Jacobian
1206 
1207    Level: intermediate
1208 
1209 .seealso: TSSetRHSJacobian(), TSComputeRHSJacobianConstant()
1210 @*/
1211 PetscErrorCode TSRHSJacobianSetReuse(TS ts,PetscBool reuse)
1212 {
1213   PetscFunctionBegin;
1214   ts->rhsjacobian.reuse = reuse;
1215   PetscFunctionReturn(0);
1216 }
1217 
1218 #undef __FUNCT__
1219 #define __FUNCT__ "TSLoad"
1220 /*@C
1221   TSLoad - Loads a KSP that has been stored in binary  with KSPView().
1222 
1223   Collective on PetscViewer
1224 
1225   Input Parameters:
1226 + newdm - the newly loaded TS, this needs to have been created with TSCreate() or
1227            some related function before a call to TSLoad().
1228 - viewer - binary file viewer, obtained from PetscViewerBinaryOpen()
1229 
1230    Level: intermediate
1231 
1232   Notes:
1233    The type is determined by the data in the file, any type set into the TS before this call is ignored.
1234 
1235   Notes for advanced users:
1236   Most users should not need to know the details of the binary storage
1237   format, since TSLoad() and TSView() completely hide these details.
1238   But for anyone who's interested, the standard binary matrix storage
1239   format is
1240 .vb
1241      has not yet been determined
1242 .ve
1243 
1244 .seealso: PetscViewerBinaryOpen(), TSView(), MatLoad(), VecLoad()
1245 @*/
1246 PetscErrorCode  TSLoad(TS ts, PetscViewer viewer)
1247 {
1248   PetscErrorCode ierr;
1249   PetscBool      isbinary;
1250   PetscInt       classid;
1251   char           type[256];
1252   DMTS           sdm;
1253   DM             dm;
1254 
1255   PetscFunctionBegin;
1256   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1257   PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,2);
1258   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);CHKERRQ(ierr);
1259   if (!isbinary) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Invalid viewer; open viewer with PetscViewerBinaryOpen()");
1260 
1261   ierr = PetscViewerBinaryRead(viewer,&classid,1,PETSC_INT);CHKERRQ(ierr);
1262   if (classid != TS_FILE_CLASSID) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_ARG_WRONG,"Not TS next in file");
1263   ierr = PetscViewerBinaryRead(viewer,type,256,PETSC_CHAR);CHKERRQ(ierr);
1264   ierr = TSSetType(ts, type);CHKERRQ(ierr);
1265   if (ts->ops->load) {
1266     ierr = (*ts->ops->load)(ts,viewer);CHKERRQ(ierr);
1267   }
1268   ierr = DMCreate(PetscObjectComm((PetscObject)ts),&dm);CHKERRQ(ierr);
1269   ierr = DMLoad(dm,viewer);CHKERRQ(ierr);
1270   ierr = TSSetDM(ts,dm);CHKERRQ(ierr);
1271   ierr = DMCreateGlobalVector(ts->dm,&ts->vec_sol);CHKERRQ(ierr);
1272   ierr = VecLoad(ts->vec_sol,viewer);CHKERRQ(ierr);
1273   ierr = DMGetDMTS(ts->dm,&sdm);CHKERRQ(ierr);
1274   ierr = DMTSLoad(sdm,viewer);CHKERRQ(ierr);
1275   PetscFunctionReturn(0);
1276 }
1277 
1278 #include <petscdraw.h>
1279 #if defined(PETSC_HAVE_AMS)
1280 #include <petscviewerams.h>
1281 #endif
1282 #undef __FUNCT__
1283 #define __FUNCT__ "TSView"
1284 /*@C
1285     TSView - Prints the TS data structure.
1286 
1287     Collective on TS
1288 
1289     Input Parameters:
1290 +   ts - the TS context obtained from TSCreate()
1291 -   viewer - visualization context
1292 
1293     Options Database Key:
1294 .   -ts_view - calls TSView() at end of TSStep()
1295 
1296     Notes:
1297     The available visualization contexts include
1298 +     PETSC_VIEWER_STDOUT_SELF - standard output (default)
1299 -     PETSC_VIEWER_STDOUT_WORLD - synchronized standard
1300          output where only the first processor opens
1301          the file.  All other processors send their
1302          data to the first processor to print.
1303 
1304     The user can open an alternative visualization context with
1305     PetscViewerASCIIOpen() - output to a specified file.
1306 
1307     Level: beginner
1308 
1309 .keywords: TS, timestep, view
1310 
1311 .seealso: PetscViewerASCIIOpen()
1312 @*/
1313 PetscErrorCode  TSView(TS ts,PetscViewer viewer)
1314 {
1315   PetscErrorCode ierr;
1316   TSType         type;
1317   PetscBool      iascii,isstring,isundials,isbinary,isdraw;
1318   DMTS           sdm;
1319 #if defined(PETSC_HAVE_AMS)
1320   PetscBool      isams;
1321 #endif
1322 
1323   PetscFunctionBegin;
1324   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1325   if (!viewer) {
1326     ierr = PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)ts),&viewer);CHKERRQ(ierr);
1327   }
1328   PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,2);
1329   PetscCheckSameComm(ts,1,viewer,2);
1330 
1331   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr);
1332   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);CHKERRQ(ierr);
1333   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);CHKERRQ(ierr);
1334   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);CHKERRQ(ierr);
1335 #if defined(PETSC_HAVE_AMS)
1336   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERAMS,&isams);CHKERRQ(ierr);
1337 #endif
1338   if (iascii) {
1339     ierr = PetscObjectPrintClassNamePrefixType((PetscObject)ts,viewer);CHKERRQ(ierr);
1340     ierr = PetscViewerASCIIPrintf(viewer,"  maximum steps=%D\n",ts->max_steps);CHKERRQ(ierr);
1341     ierr = PetscViewerASCIIPrintf(viewer,"  maximum time=%G\n",ts->max_time);CHKERRQ(ierr);
1342     if (ts->problem_type == TS_NONLINEAR) {
1343       ierr = PetscViewerASCIIPrintf(viewer,"  total number of nonlinear solver iterations=%D\n",ts->snes_its);CHKERRQ(ierr);
1344       ierr = PetscViewerASCIIPrintf(viewer,"  total number of nonlinear solve failures=%D\n",ts->num_snes_failures);CHKERRQ(ierr);
1345     }
1346     ierr = PetscViewerASCIIPrintf(viewer,"  total number of linear solver iterations=%D\n",ts->ksp_its);CHKERRQ(ierr);
1347     ierr = PetscViewerASCIIPrintf(viewer,"  total number of rejected steps=%D\n",ts->reject);CHKERRQ(ierr);
1348     ierr = DMGetDMTS(ts->dm,&sdm);CHKERRQ(ierr);
1349     ierr = DMTSView(sdm,viewer);CHKERRQ(ierr);
1350     if (ts->ops->view) {
1351       ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
1352       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1353       ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
1354     }
1355   } else if (isstring) {
1356     ierr = TSGetType(ts,&type);CHKERRQ(ierr);
1357     ierr = PetscViewerStringSPrintf(viewer," %-7.7s",type);CHKERRQ(ierr);
1358   } else if (isbinary) {
1359     PetscInt    classid = TS_FILE_CLASSID;
1360     MPI_Comm    comm;
1361     PetscMPIInt rank;
1362     char        type[256];
1363 
1364     ierr = PetscObjectGetComm((PetscObject)ts,&comm);CHKERRQ(ierr);
1365     ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
1366     if (!rank) {
1367       ierr = PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT,PETSC_FALSE);CHKERRQ(ierr);
1368       ierr = PetscStrncpy(type,((PetscObject)ts)->type_name,256);CHKERRQ(ierr);
1369       ierr = PetscViewerBinaryWrite(viewer,type,256,PETSC_CHAR,PETSC_FALSE);CHKERRQ(ierr);
1370     }
1371     if (ts->ops->view) {
1372       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1373     }
1374     ierr = DMView(ts->dm,viewer);CHKERRQ(ierr);
1375     ierr = VecView(ts->vec_sol,viewer);CHKERRQ(ierr);
1376     ierr = DMGetDMTS(ts->dm,&sdm);CHKERRQ(ierr);
1377     ierr = DMTSView(sdm,viewer);CHKERRQ(ierr);
1378   } else if (isdraw) {
1379     PetscDraw draw;
1380     char      str[36];
1381     PetscReal x,y,bottom,h;
1382 
1383     ierr   = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr);
1384     ierr   = PetscDrawGetCurrentPoint(draw,&x,&y);CHKERRQ(ierr);
1385     ierr   = PetscStrcpy(str,"TS: ");CHKERRQ(ierr);
1386     ierr   = PetscStrcat(str,((PetscObject)ts)->type_name);CHKERRQ(ierr);
1387     ierr   = PetscDrawBoxedString(draw,x,y,PETSC_DRAW_BLACK,PETSC_DRAW_BLACK,str,NULL,&h);CHKERRQ(ierr);
1388     bottom = y - h;
1389     ierr   = PetscDrawPushCurrentPoint(draw,x,bottom);CHKERRQ(ierr);
1390     if (ts->ops->view) {
1391       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1392     }
1393     ierr = PetscDrawPopCurrentPoint(draw);CHKERRQ(ierr);
1394 #if defined(PETSC_HAVE_AMS)
1395   } else if (isams) {
1396     if (((PetscObject)ts)->amsmem == -1) {
1397       ierr = PetscObjectViewAMS((PetscObject)ts,viewer);CHKERRQ(ierr);
1398       PetscStackCallAMS(AMS_Memory_take_access,(((PetscObject)ts)->amsmem));
1399       PetscStackCallAMS(AMS_Memory_add_field,(((PetscObject)ts)->amsmem,"time step",&ts->steps,1,AMS_INT,AMS_READ,AMS_COMMON,AMS_REDUCT_UNDEF));
1400       PetscStackCallAMS(AMS_Memory_add_field,(((PetscObject)ts)->amsmem,"time",&ts->ptime,1,AMS_DOUBLE,AMS_READ,AMS_COMMON,AMS_REDUCT_UNDEF));
1401       PetscStackCallAMS(AMS_Memory_grant_access,(((PetscObject)ts)->amsmem));
1402     }
1403     if (ts->ops->view) {
1404       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1405     }
1406 #endif
1407   }
1408 
1409   ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
1410   ierr = PetscObjectTypeCompare((PetscObject)ts,TSSUNDIALS,&isundials);CHKERRQ(ierr);
1411   ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
1412   PetscFunctionReturn(0);
1413 }
1414 
1415 
1416 #undef __FUNCT__
1417 #define __FUNCT__ "TSSetApplicationContext"
1418 /*@
1419    TSSetApplicationContext - Sets an optional user-defined context for
1420    the timesteppers.
1421 
1422    Logically Collective on TS
1423 
1424    Input Parameters:
1425 +  ts - the TS context obtained from TSCreate()
1426 -  usrP - optional user context
1427 
1428    Level: intermediate
1429 
1430 .keywords: TS, timestep, set, application, context
1431 
1432 .seealso: TSGetApplicationContext()
1433 @*/
1434 PetscErrorCode  TSSetApplicationContext(TS ts,void *usrP)
1435 {
1436   PetscFunctionBegin;
1437   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1438   ts->user = usrP;
1439   PetscFunctionReturn(0);
1440 }
1441 
1442 #undef __FUNCT__
1443 #define __FUNCT__ "TSGetApplicationContext"
1444 /*@
1445     TSGetApplicationContext - Gets the user-defined context for the
1446     timestepper.
1447 
1448     Not Collective
1449 
1450     Input Parameter:
1451 .   ts - the TS context obtained from TSCreate()
1452 
1453     Output Parameter:
1454 .   usrP - user context
1455 
1456     Level: intermediate
1457 
1458 .keywords: TS, timestep, get, application, context
1459 
1460 .seealso: TSSetApplicationContext()
1461 @*/
1462 PetscErrorCode  TSGetApplicationContext(TS ts,void *usrP)
1463 {
1464   PetscFunctionBegin;
1465   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1466   *(void**)usrP = ts->user;
1467   PetscFunctionReturn(0);
1468 }
1469 
1470 #undef __FUNCT__
1471 #define __FUNCT__ "TSGetTimeStepNumber"
1472 /*@
1473    TSGetTimeStepNumber - Gets the number of time steps completed.
1474 
1475    Not Collective
1476 
1477    Input Parameter:
1478 .  ts - the TS context obtained from TSCreate()
1479 
1480    Output Parameter:
1481 .  iter - number of steps completed so far
1482 
1483    Level: intermediate
1484 
1485 .keywords: TS, timestep, get, iteration, number
1486 .seealso: TSGetTime(), TSGetTimeStep(), TSSetPreStep(), TSSetPreStage(), TSSetPostStep()
1487 @*/
1488 PetscErrorCode  TSGetTimeStepNumber(TS ts,PetscInt *iter)
1489 {
1490   PetscFunctionBegin;
1491   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1492   PetscValidIntPointer(iter,2);
1493   *iter = ts->steps;
1494   PetscFunctionReturn(0);
1495 }
1496 
1497 #undef __FUNCT__
1498 #define __FUNCT__ "TSSetInitialTimeStep"
1499 /*@
1500    TSSetInitialTimeStep - Sets the initial timestep to be used,
1501    as well as the initial time.
1502 
1503    Logically Collective on TS
1504 
1505    Input Parameters:
1506 +  ts - the TS context obtained from TSCreate()
1507 .  initial_time - the initial time
1508 -  time_step - the size of the timestep
1509 
1510    Level: intermediate
1511 
1512 .seealso: TSSetTimeStep(), TSGetTimeStep()
1513 
1514 .keywords: TS, set, initial, timestep
1515 @*/
1516 PetscErrorCode  TSSetInitialTimeStep(TS ts,PetscReal initial_time,PetscReal time_step)
1517 {
1518   PetscErrorCode ierr;
1519 
1520   PetscFunctionBegin;
1521   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1522   ierr = TSSetTimeStep(ts,time_step);CHKERRQ(ierr);
1523   ierr = TSSetTime(ts,initial_time);CHKERRQ(ierr);
1524   PetscFunctionReturn(0);
1525 }
1526 
1527 #undef __FUNCT__
1528 #define __FUNCT__ "TSSetTimeStep"
1529 /*@
1530    TSSetTimeStep - Allows one to reset the timestep at any time,
1531    useful for simple pseudo-timestepping codes.
1532 
1533    Logically Collective on TS
1534 
1535    Input Parameters:
1536 +  ts - the TS context obtained from TSCreate()
1537 -  time_step - the size of the timestep
1538 
1539    Level: intermediate
1540 
1541 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
1542 
1543 .keywords: TS, set, timestep
1544 @*/
1545 PetscErrorCode  TSSetTimeStep(TS ts,PetscReal time_step)
1546 {
1547   PetscFunctionBegin;
1548   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1549   PetscValidLogicalCollectiveReal(ts,time_step,2);
1550   ts->time_step      = time_step;
1551   ts->time_step_orig = time_step;
1552   PetscFunctionReturn(0);
1553 }
1554 
1555 #undef __FUNCT__
1556 #define __FUNCT__ "TSSetExactFinalTime"
1557 /*@
1558    TSSetExactFinalTime - Determines whether to adapt the final time step to
1559      match the exact final time, interpolate solution to the exact final time,
1560      or just return at the final time TS computed.
1561 
1562   Logically Collective on TS
1563 
1564    Input Parameter:
1565 +   ts - the time-step context
1566 -   eftopt - exact final time option
1567 
1568    Level: beginner
1569 
1570 .seealso: TSExactFinalTimeOption
1571 @*/
1572 PetscErrorCode  TSSetExactFinalTime(TS ts,TSExactFinalTimeOption eftopt)
1573 {
1574   PetscFunctionBegin;
1575   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1576   PetscValidLogicalCollectiveEnum(ts,eftopt,2);
1577   ts->exact_final_time = eftopt;
1578   PetscFunctionReturn(0);
1579 }
1580 
1581 #undef __FUNCT__
1582 #define __FUNCT__ "TSGetTimeStep"
1583 /*@
1584    TSGetTimeStep - Gets the current timestep size.
1585 
1586    Not Collective
1587 
1588    Input Parameter:
1589 .  ts - the TS context obtained from TSCreate()
1590 
1591    Output Parameter:
1592 .  dt - the current timestep size
1593 
1594    Level: intermediate
1595 
1596 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
1597 
1598 .keywords: TS, get, timestep
1599 @*/
1600 PetscErrorCode  TSGetTimeStep(TS ts,PetscReal *dt)
1601 {
1602   PetscFunctionBegin;
1603   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1604   PetscValidRealPointer(dt,2);
1605   *dt = ts->time_step;
1606   PetscFunctionReturn(0);
1607 }
1608 
1609 #undef __FUNCT__
1610 #define __FUNCT__ "TSGetSolution"
1611 /*@
1612    TSGetSolution - Returns the solution at the present timestep. It
1613    is valid to call this routine inside the function that you are evaluating
1614    in order to move to the new timestep. This vector not changed until
1615    the solution at the next timestep has been calculated.
1616 
1617    Not Collective, but Vec returned is parallel if TS is parallel
1618 
1619    Input Parameter:
1620 .  ts - the TS context obtained from TSCreate()
1621 
1622    Output Parameter:
1623 .  v - the vector containing the solution
1624 
1625    Level: intermediate
1626 
1627 .seealso: TSGetTimeStep()
1628 
1629 .keywords: TS, timestep, get, solution
1630 @*/
1631 PetscErrorCode  TSGetSolution(TS ts,Vec *v)
1632 {
1633   PetscFunctionBegin;
1634   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1635   PetscValidPointer(v,2);
1636   *v = ts->vec_sol;
1637   PetscFunctionReturn(0);
1638 }
1639 
1640 /* ----- Routines to initialize and destroy a timestepper ---- */
1641 #undef __FUNCT__
1642 #define __FUNCT__ "TSSetProblemType"
1643 /*@
1644   TSSetProblemType - Sets the type of problem to be solved.
1645 
1646   Not collective
1647 
1648   Input Parameters:
1649 + ts   - The TS
1650 - type - One of TS_LINEAR, TS_NONLINEAR where these types refer to problems of the forms
1651 .vb
1652          U_t - A U = 0      (linear)
1653          U_t - A(t) U = 0   (linear)
1654          F(t,U,U_t) = 0     (nonlinear)
1655 .ve
1656 
1657    Level: beginner
1658 
1659 .keywords: TS, problem type
1660 .seealso: TSSetUp(), TSProblemType, TS
1661 @*/
1662 PetscErrorCode  TSSetProblemType(TS ts, TSProblemType type)
1663 {
1664   PetscErrorCode ierr;
1665 
1666   PetscFunctionBegin;
1667   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
1668   ts->problem_type = type;
1669   if (type == TS_LINEAR) {
1670     SNES snes;
1671     ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1672     ierr = SNESSetType(snes,SNESKSPONLY);CHKERRQ(ierr);
1673   }
1674   PetscFunctionReturn(0);
1675 }
1676 
1677 #undef __FUNCT__
1678 #define __FUNCT__ "TSGetProblemType"
1679 /*@C
1680   TSGetProblemType - Gets the type of problem to be solved.
1681 
1682   Not collective
1683 
1684   Input Parameter:
1685 . ts   - The TS
1686 
1687   Output Parameter:
1688 . type - One of TS_LINEAR, TS_NONLINEAR where these types refer to problems of the forms
1689 .vb
1690          M U_t = A U
1691          M(t) U_t = A(t) U
1692          F(t,U,U_t)
1693 .ve
1694 
1695    Level: beginner
1696 
1697 .keywords: TS, problem type
1698 .seealso: TSSetUp(), TSProblemType, TS
1699 @*/
1700 PetscErrorCode  TSGetProblemType(TS ts, TSProblemType *type)
1701 {
1702   PetscFunctionBegin;
1703   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
1704   PetscValidIntPointer(type,2);
1705   *type = ts->problem_type;
1706   PetscFunctionReturn(0);
1707 }
1708 
1709 #undef __FUNCT__
1710 #define __FUNCT__ "TSSetUp"
1711 /*@
1712    TSSetUp - Sets up the internal data structures for the later use
1713    of a timestepper.
1714 
1715    Collective on TS
1716 
1717    Input Parameter:
1718 .  ts - the TS context obtained from TSCreate()
1719 
1720    Notes:
1721    For basic use of the TS solvers the user need not explicitly call
1722    TSSetUp(), since these actions will automatically occur during
1723    the call to TSStep().  However, if one wishes to control this
1724    phase separately, TSSetUp() should be called after TSCreate()
1725    and optional routines of the form TSSetXXX(), but before TSStep().
1726 
1727    Level: advanced
1728 
1729 .keywords: TS, timestep, setup
1730 
1731 .seealso: TSCreate(), TSStep(), TSDestroy()
1732 @*/
1733 PetscErrorCode  TSSetUp(TS ts)
1734 {
1735   PetscErrorCode ierr;
1736   DM             dm;
1737   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
1738   PetscErrorCode (*jac)(SNES,Vec,Mat*,Mat*,MatStructure*,void*);
1739   TSIJacobian    ijac;
1740   TSRHSJacobian  rhsjac;
1741 
1742   PetscFunctionBegin;
1743   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1744   if (ts->setupcalled) PetscFunctionReturn(0);
1745 
1746   if (!((PetscObject)ts)->type_name) {
1747     ierr = TSSetType(ts,TSEULER);CHKERRQ(ierr);
1748   }
1749 
1750   if (!ts->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Must call TSSetSolution() first");
1751 
1752   ierr = TSGetAdapt(ts,&ts->adapt);CHKERRQ(ierr);
1753 
1754   if (ts->rhsjacobian.reuse) {
1755     Mat Amat,Pmat;
1756     SNES snes;
1757     ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1758     ierr = SNESGetJacobian(snes,&Amat,&Pmat,NULL,NULL);CHKERRQ(ierr);
1759     /* Matching matrices implies that an IJacobian is NOT set, because if it had been set, the IJacobian's matrix would
1760      * have displaced the RHS matrix */
1761     if (Amat == ts->Arhs) {
1762       ierr = MatDuplicate(ts->Arhs,MAT_DO_NOT_COPY_VALUES,&Amat);CHKERRQ(ierr);
1763       ierr = SNESSetJacobian(snes,Amat,NULL,NULL,NULL);CHKERRQ(ierr);
1764       ierr = MatDestroy(&Amat);CHKERRQ(ierr);
1765     }
1766     if (Pmat == ts->Brhs) {
1767       ierr = MatDuplicate(ts->Brhs,MAT_DO_NOT_COPY_VALUES,&Pmat);CHKERRQ(ierr);
1768       ierr = SNESSetJacobian(snes,NULL,Pmat,NULL,NULL);CHKERRQ(ierr);
1769       ierr = MatDestroy(&Pmat);CHKERRQ(ierr);
1770     }
1771   }
1772 
1773   if (ts->ops->setup) {
1774     ierr = (*ts->ops->setup)(ts);CHKERRQ(ierr);
1775   }
1776 
1777   /* in the case where we've set a DMTSFunction or what have you, we need the default SNESFunction
1778    to be set right but can't do it elsewhere due to the overreliance on ctx=ts.
1779    */
1780   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1781   ierr = DMSNESGetFunction(dm,&func,NULL);CHKERRQ(ierr);
1782   if (!func) {
1783     ierr =DMSNESSetFunction(dm,SNESTSFormFunction,ts);CHKERRQ(ierr);
1784   }
1785   /* if the SNES doesn't have a jacobian set and the TS has an ijacobian or rhsjacobian set, set the SNES to use it.
1786      Otherwise, the SNES will use coloring internally to form the Jacobian.
1787    */
1788   ierr = DMSNESGetJacobian(dm,&jac,NULL);CHKERRQ(ierr);
1789   ierr = DMTSGetIJacobian(dm,&ijac,NULL);CHKERRQ(ierr);
1790   ierr = DMTSGetRHSJacobian(dm,&rhsjac,NULL);CHKERRQ(ierr);
1791   if (!jac && (ijac || rhsjac)) {
1792     ierr = DMSNESSetJacobian(dm,SNESTSFormJacobian,ts);CHKERRQ(ierr);
1793   }
1794   ts->setupcalled = PETSC_TRUE;
1795   PetscFunctionReturn(0);
1796 }
1797 
1798 #undef __FUNCT__
1799 #define __FUNCT__ "TSReset"
1800 /*@
1801    TSReset - Resets a TS context and removes any allocated Vecs and Mats.
1802 
1803    Collective on TS
1804 
1805    Input Parameter:
1806 .  ts - the TS context obtained from TSCreate()
1807 
1808    Level: beginner
1809 
1810 .keywords: TS, timestep, reset
1811 
1812 .seealso: TSCreate(), TSSetup(), TSDestroy()
1813 @*/
1814 PetscErrorCode  TSReset(TS ts)
1815 {
1816   PetscErrorCode ierr;
1817 
1818   PetscFunctionBegin;
1819   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1820   if (ts->ops->reset) {
1821     ierr = (*ts->ops->reset)(ts);CHKERRQ(ierr);
1822   }
1823   if (ts->snes) {ierr = SNESReset(ts->snes);CHKERRQ(ierr);}
1824 
1825   ierr = MatDestroy(&ts->Arhs);CHKERRQ(ierr);
1826   ierr = MatDestroy(&ts->Brhs);CHKERRQ(ierr);
1827   ierr = VecDestroy(&ts->Frhs);CHKERRQ(ierr);
1828   ierr = VecDestroy(&ts->vec_sol);CHKERRQ(ierr);
1829   ierr = VecDestroy(&ts->vatol);CHKERRQ(ierr);
1830   ierr = VecDestroy(&ts->vrtol);CHKERRQ(ierr);
1831   ierr = VecDestroyVecs(ts->nwork,&ts->work);CHKERRQ(ierr);
1832 
1833   ts->setupcalled = PETSC_FALSE;
1834   PetscFunctionReturn(0);
1835 }
1836 
1837 #undef __FUNCT__
1838 #define __FUNCT__ "TSDestroy"
1839 /*@
1840    TSDestroy - Destroys the timestepper context that was created
1841    with TSCreate().
1842 
1843    Collective on TS
1844 
1845    Input Parameter:
1846 .  ts - the TS context obtained from TSCreate()
1847 
1848    Level: beginner
1849 
1850 .keywords: TS, timestepper, destroy
1851 
1852 .seealso: TSCreate(), TSSetUp(), TSSolve()
1853 @*/
1854 PetscErrorCode  TSDestroy(TS *ts)
1855 {
1856   PetscErrorCode ierr;
1857 
1858   PetscFunctionBegin;
1859   if (!*ts) PetscFunctionReturn(0);
1860   PetscValidHeaderSpecific((*ts),TS_CLASSID,1);
1861   if (--((PetscObject)(*ts))->refct > 0) {*ts = 0; PetscFunctionReturn(0);}
1862 
1863   ierr = TSReset((*ts));CHKERRQ(ierr);
1864 
1865   /* if memory was published with AMS then destroy it */
1866   ierr = PetscObjectAMSViewOff((PetscObject)*ts);CHKERRQ(ierr);
1867   if ((*ts)->ops->destroy) {ierr = (*(*ts)->ops->destroy)((*ts));CHKERRQ(ierr);}
1868 
1869   ierr = TSAdaptDestroy(&(*ts)->adapt);CHKERRQ(ierr);
1870   ierr = SNESDestroy(&(*ts)->snes);CHKERRQ(ierr);
1871   ierr = DMDestroy(&(*ts)->dm);CHKERRQ(ierr);
1872   ierr = TSMonitorCancel((*ts));CHKERRQ(ierr);
1873 
1874   ierr = PetscHeaderDestroy(ts);CHKERRQ(ierr);
1875   PetscFunctionReturn(0);
1876 }
1877 
1878 #undef __FUNCT__
1879 #define __FUNCT__ "TSGetSNES"
1880 /*@
1881    TSGetSNES - Returns the SNES (nonlinear solver) associated with
1882    a TS (timestepper) context. Valid only for nonlinear problems.
1883 
1884    Not Collective, but SNES is parallel if TS is parallel
1885 
1886    Input Parameter:
1887 .  ts - the TS context obtained from TSCreate()
1888 
1889    Output Parameter:
1890 .  snes - the nonlinear solver context
1891 
1892    Notes:
1893    The user can then directly manipulate the SNES context to set various
1894    options, etc.  Likewise, the user can then extract and manipulate the
1895    KSP, KSP, and PC contexts as well.
1896 
1897    TSGetSNES() does not work for integrators that do not use SNES; in
1898    this case TSGetSNES() returns NULL in snes.
1899 
1900    Level: beginner
1901 
1902 .keywords: timestep, get, SNES
1903 @*/
1904 PetscErrorCode  TSGetSNES(TS ts,SNES *snes)
1905 {
1906   PetscErrorCode ierr;
1907 
1908   PetscFunctionBegin;
1909   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1910   PetscValidPointer(snes,2);
1911   if (!ts->snes) {
1912     ierr = SNESCreate(PetscObjectComm((PetscObject)ts),&ts->snes);CHKERRQ(ierr);
1913     ierr = SNESSetFunction(ts->snes,NULL,SNESTSFormFunction,ts);CHKERRQ(ierr);
1914     ierr = PetscLogObjectParent(ts,ts->snes);CHKERRQ(ierr);
1915     ierr = PetscObjectIncrementTabLevel((PetscObject)ts->snes,(PetscObject)ts,1);CHKERRQ(ierr);
1916     if (ts->dm) {ierr = SNESSetDM(ts->snes,ts->dm);CHKERRQ(ierr);}
1917     if (ts->problem_type == TS_LINEAR) {
1918       ierr = SNESSetType(ts->snes,SNESKSPONLY);CHKERRQ(ierr);
1919     }
1920   }
1921   *snes = ts->snes;
1922   PetscFunctionReturn(0);
1923 }
1924 
1925 #undef __FUNCT__
1926 #define __FUNCT__ "TSSetSNES"
1927 /*@
1928    TSSetSNES - Set the SNES (nonlinear solver) to be used by the timestepping context
1929 
1930    Collective
1931 
1932    Input Parameter:
1933 +  ts - the TS context obtained from TSCreate()
1934 -  snes - the nonlinear solver context
1935 
1936    Notes:
1937    Most users should have the TS created by calling TSGetSNES()
1938 
1939    Level: developer
1940 
1941 .keywords: timestep, set, SNES
1942 @*/
1943 PetscErrorCode TSSetSNES(TS ts,SNES snes)
1944 {
1945   PetscErrorCode ierr;
1946   PetscErrorCode (*func)(SNES,Vec,Mat*,Mat*,MatStructure*,void*);
1947 
1948   PetscFunctionBegin;
1949   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1950   PetscValidHeaderSpecific(snes,SNES_CLASSID,2);
1951   ierr = PetscObjectReference((PetscObject)snes);CHKERRQ(ierr);
1952   ierr = SNESDestroy(&ts->snes);CHKERRQ(ierr);
1953 
1954   ts->snes = snes;
1955 
1956   ierr = SNESSetFunction(ts->snes,NULL,SNESTSFormFunction,ts);CHKERRQ(ierr);
1957   ierr = SNESGetJacobian(ts->snes,NULL,NULL,&func,NULL);CHKERRQ(ierr);
1958   if (func == SNESTSFormJacobian) {
1959     ierr = SNESSetJacobian(ts->snes,NULL,NULL,SNESTSFormJacobian,ts);CHKERRQ(ierr);
1960   }
1961   PetscFunctionReturn(0);
1962 }
1963 
1964 #undef __FUNCT__
1965 #define __FUNCT__ "TSGetKSP"
1966 /*@
1967    TSGetKSP - Returns the KSP (linear solver) associated with
1968    a TS (timestepper) context.
1969 
1970    Not Collective, but KSP is parallel if TS is parallel
1971 
1972    Input Parameter:
1973 .  ts - the TS context obtained from TSCreate()
1974 
1975    Output Parameter:
1976 .  ksp - the nonlinear solver context
1977 
1978    Notes:
1979    The user can then directly manipulate the KSP context to set various
1980    options, etc.  Likewise, the user can then extract and manipulate the
1981    KSP and PC contexts as well.
1982 
1983    TSGetKSP() does not work for integrators that do not use KSP;
1984    in this case TSGetKSP() returns NULL in ksp.
1985 
1986    Level: beginner
1987 
1988 .keywords: timestep, get, KSP
1989 @*/
1990 PetscErrorCode  TSGetKSP(TS ts,KSP *ksp)
1991 {
1992   PetscErrorCode ierr;
1993   SNES           snes;
1994 
1995   PetscFunctionBegin;
1996   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1997   PetscValidPointer(ksp,2);
1998   if (!((PetscObject)ts)->type_name) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"KSP is not created yet. Call TSSetType() first");
1999   if (ts->problem_type != TS_LINEAR) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Linear only; use TSGetSNES()");
2000   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2001   ierr = SNESGetKSP(snes,ksp);CHKERRQ(ierr);
2002   PetscFunctionReturn(0);
2003 }
2004 
2005 /* ----------- Routines to set solver parameters ---------- */
2006 
2007 #undef __FUNCT__
2008 #define __FUNCT__ "TSGetDuration"
2009 /*@
2010    TSGetDuration - Gets the maximum number of timesteps to use and
2011    maximum time for iteration.
2012 
2013    Not Collective
2014 
2015    Input Parameters:
2016 +  ts       - the TS context obtained from TSCreate()
2017 .  maxsteps - maximum number of iterations to use, or NULL
2018 -  maxtime  - final time to iterate to, or NULL
2019 
2020    Level: intermediate
2021 
2022 .keywords: TS, timestep, get, maximum, iterations, time
2023 @*/
2024 PetscErrorCode  TSGetDuration(TS ts, PetscInt *maxsteps, PetscReal *maxtime)
2025 {
2026   PetscFunctionBegin;
2027   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2028   if (maxsteps) {
2029     PetscValidIntPointer(maxsteps,2);
2030     *maxsteps = ts->max_steps;
2031   }
2032   if (maxtime) {
2033     PetscValidScalarPointer(maxtime,3);
2034     *maxtime = ts->max_time;
2035   }
2036   PetscFunctionReturn(0);
2037 }
2038 
2039 #undef __FUNCT__
2040 #define __FUNCT__ "TSSetDuration"
2041 /*@
2042    TSSetDuration - Sets the maximum number of timesteps to use and
2043    maximum time for iteration.
2044 
2045    Logically Collective on TS
2046 
2047    Input Parameters:
2048 +  ts - the TS context obtained from TSCreate()
2049 .  maxsteps - maximum number of iterations to use
2050 -  maxtime - final time to iterate to
2051 
2052    Options Database Keys:
2053 .  -ts_max_steps <maxsteps> - Sets maxsteps
2054 .  -ts_final_time <maxtime> - Sets maxtime
2055 
2056    Notes:
2057    The default maximum number of iterations is 5000. Default time is 5.0
2058 
2059    Level: intermediate
2060 
2061 .keywords: TS, timestep, set, maximum, iterations
2062 
2063 .seealso: TSSetExactFinalTime()
2064 @*/
2065 PetscErrorCode  TSSetDuration(TS ts,PetscInt maxsteps,PetscReal maxtime)
2066 {
2067   PetscFunctionBegin;
2068   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2069   PetscValidLogicalCollectiveInt(ts,maxsteps,2);
2070   PetscValidLogicalCollectiveReal(ts,maxtime,2);
2071   if (maxsteps >= 0) ts->max_steps = maxsteps;
2072   if (maxtime != PETSC_DEFAULT) ts->max_time = maxtime;
2073   PetscFunctionReturn(0);
2074 }
2075 
2076 #undef __FUNCT__
2077 #define __FUNCT__ "TSSetSolution"
2078 /*@
2079    TSSetSolution - Sets the initial solution vector
2080    for use by the TS routines.
2081 
2082    Logically Collective on TS and Vec
2083 
2084    Input Parameters:
2085 +  ts - the TS context obtained from TSCreate()
2086 -  u - the solution vector
2087 
2088    Level: beginner
2089 
2090 .keywords: TS, timestep, set, solution, initial conditions
2091 @*/
2092 PetscErrorCode  TSSetSolution(TS ts,Vec u)
2093 {
2094   PetscErrorCode ierr;
2095   DM             dm;
2096 
2097   PetscFunctionBegin;
2098   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2099   PetscValidHeaderSpecific(u,VEC_CLASSID,2);
2100   ierr = PetscObjectReference((PetscObject)u);CHKERRQ(ierr);
2101   ierr = VecDestroy(&ts->vec_sol);CHKERRQ(ierr);
2102 
2103   ts->vec_sol = u;
2104 
2105   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
2106   ierr = DMShellSetGlobalVector(dm,u);CHKERRQ(ierr);
2107   PetscFunctionReturn(0);
2108 }
2109 
2110 #undef __FUNCT__
2111 #define __FUNCT__ "TSSetPreStep"
2112 /*@C
2113   TSSetPreStep - Sets the general-purpose function
2114   called once at the beginning of each time step.
2115 
2116   Logically Collective on TS
2117 
2118   Input Parameters:
2119 + ts   - The TS context obtained from TSCreate()
2120 - func - The function
2121 
2122   Calling sequence of func:
2123 . func (TS ts);
2124 
2125   Level: intermediate
2126 
2127   Note:
2128   If a step is rejected, TSStep() will call this routine again before each attempt.
2129   The last completed time step number can be queried using TSGetTimeStepNumber(), the
2130   size of the step being attempted can be obtained using TSGetTimeStep().
2131 
2132 .keywords: TS, timestep
2133 .seealso: TSSetPreStage(), TSSetPostStep(), TSStep()
2134 @*/
2135 PetscErrorCode  TSSetPreStep(TS ts, PetscErrorCode (*func)(TS))
2136 {
2137   PetscFunctionBegin;
2138   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2139   ts->prestep = func;
2140   PetscFunctionReturn(0);
2141 }
2142 
2143 #undef __FUNCT__
2144 #define __FUNCT__ "TSPreStep"
2145 /*@
2146   TSPreStep - Runs the user-defined pre-step function.
2147 
2148   Collective on TS
2149 
2150   Input Parameters:
2151 . ts   - The TS context obtained from TSCreate()
2152 
2153   Notes:
2154   TSPreStep() is typically used within time stepping implementations,
2155   so most users would not generally call this routine themselves.
2156 
2157   Level: developer
2158 
2159 .keywords: TS, timestep
2160 .seealso: TSSetPreStep(), TSPreStage(), TSPostStep()
2161 @*/
2162 PetscErrorCode  TSPreStep(TS ts)
2163 {
2164   PetscErrorCode ierr;
2165 
2166   PetscFunctionBegin;
2167   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2168   if (ts->prestep) {
2169     PetscStackCallStandard((*ts->prestep),(ts));
2170   }
2171   PetscFunctionReturn(0);
2172 }
2173 
2174 #undef __FUNCT__
2175 #define __FUNCT__ "TSSetPreStage"
2176 /*@C
2177   TSSetPreStage - Sets the general-purpose function
2178   called once at the beginning of each stage.
2179 
2180   Logically Collective on TS
2181 
2182   Input Parameters:
2183 + ts   - The TS context obtained from TSCreate()
2184 - func - The function
2185 
2186   Calling sequence of func:
2187 . PetscErrorCode func(TS ts, PetscReal stagetime);
2188 
2189   Level: intermediate
2190 
2191   Note:
2192   There may be several stages per time step. If the solve for a given stage fails, the step may be rejected and retried.
2193   The time step number being computed can be queried using TSGetTimeStepNumber() and the total size of the step being
2194   attempted can be obtained using TSGetTimeStep(). The time at the start of the step is available via TSGetTime().
2195 
2196 .keywords: TS, timestep
2197 .seealso: TSSetPreStep(), TSSetPostStep(), TSGetApplicationContext()
2198 @*/
2199 PetscErrorCode  TSSetPreStage(TS ts, PetscErrorCode (*func)(TS,PetscReal))
2200 {
2201   PetscFunctionBegin;
2202   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2203   ts->prestage = func;
2204   PetscFunctionReturn(0);
2205 }
2206 
2207 #undef __FUNCT__
2208 #define __FUNCT__ "TSPreStage"
2209 /*@
2210   TSPreStage - Runs the user-defined pre-stage function set using TSSetPreStage()
2211 
2212   Collective on TS
2213 
2214   Input Parameters:
2215 . ts   - The TS context obtained from TSCreate()
2216 
2217   Notes:
2218   TSPreStage() is typically used within time stepping implementations,
2219   most users would not generally call this routine themselves.
2220 
2221   Level: developer
2222 
2223 .keywords: TS, timestep
2224 .seealso: TSSetPreStep(), TSPreStep(), TSPostStep()
2225 @*/
2226 PetscErrorCode  TSPreStage(TS ts, PetscReal stagetime)
2227 {
2228   PetscErrorCode ierr;
2229 
2230   PetscFunctionBegin;
2231   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2232   if (ts->prestage) {
2233     PetscStackCallStandard((*ts->prestage),(ts,stagetime));
2234   }
2235   PetscFunctionReturn(0);
2236 }
2237 
2238 #undef __FUNCT__
2239 #define __FUNCT__ "TSSetPostStep"
2240 /*@C
2241   TSSetPostStep - Sets the general-purpose function
2242   called once at the end of each time step.
2243 
2244   Logically Collective on TS
2245 
2246   Input Parameters:
2247 + ts   - The TS context obtained from TSCreate()
2248 - func - The function
2249 
2250   Calling sequence of func:
2251 $ func (TS ts);
2252 
2253   Level: intermediate
2254 
2255 .keywords: TS, timestep
2256 .seealso: TSSetPreStep(), TSSetPreStage(), TSGetTimeStep(), TSGetTimeStepNumber(), TSGetTime()
2257 @*/
2258 PetscErrorCode  TSSetPostStep(TS ts, PetscErrorCode (*func)(TS))
2259 {
2260   PetscFunctionBegin;
2261   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2262   ts->poststep = func;
2263   PetscFunctionReturn(0);
2264 }
2265 
2266 #undef __FUNCT__
2267 #define __FUNCT__ "TSPostStep"
2268 /*@
2269   TSPostStep - Runs the user-defined post-step function.
2270 
2271   Collective on TS
2272 
2273   Input Parameters:
2274 . ts   - The TS context obtained from TSCreate()
2275 
2276   Notes:
2277   TSPostStep() is typically used within time stepping implementations,
2278   so most users would not generally call this routine themselves.
2279 
2280   Level: developer
2281 
2282 .keywords: TS, timestep
2283 @*/
2284 PetscErrorCode  TSPostStep(TS ts)
2285 {
2286   PetscErrorCode ierr;
2287 
2288   PetscFunctionBegin;
2289   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2290   if (ts->poststep) {
2291     PetscStackCallStandard((*ts->poststep),(ts));
2292   }
2293   PetscFunctionReturn(0);
2294 }
2295 
2296 /* ------------ Routines to set performance monitoring options ----------- */
2297 
2298 #undef __FUNCT__
2299 #define __FUNCT__ "TSMonitorSet"
2300 /*@C
2301    TSMonitorSet - Sets an ADDITIONAL function that is to be used at every
2302    timestep to display the iteration's  progress.
2303 
2304    Logically Collective on TS
2305 
2306    Input Parameters:
2307 +  ts - the TS context obtained from TSCreate()
2308 .  monitor - monitoring routine
2309 .  mctx - [optional] user-defined context for private data for the
2310              monitor routine (use NULL if no context is desired)
2311 -  monitordestroy - [optional] routine that frees monitor context
2312           (may be NULL)
2313 
2314    Calling sequence of monitor:
2315 $    int monitor(TS ts,PetscInt steps,PetscReal time,Vec u,void *mctx)
2316 
2317 +    ts - the TS context
2318 .    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
2319                                been interpolated to)
2320 .    time - current time
2321 .    u - current iterate
2322 -    mctx - [optional] monitoring context
2323 
2324    Notes:
2325    This routine adds an additional monitor to the list of monitors that
2326    already has been loaded.
2327 
2328    Fortran notes: Only a single monitor function can be set for each TS object
2329 
2330    Level: intermediate
2331 
2332 .keywords: TS, timestep, set, monitor
2333 
2334 .seealso: TSMonitorDefault(), TSMonitorCancel()
2335 @*/
2336 PetscErrorCode  TSMonitorSet(TS ts,PetscErrorCode (*monitor)(TS,PetscInt,PetscReal,Vec,void*),void *mctx,PetscErrorCode (*mdestroy)(void**))
2337 {
2338   PetscFunctionBegin;
2339   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2340   if (ts->numbermonitors >= MAXTSMONITORS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
2341   ts->monitor[ts->numbermonitors]          = monitor;
2342   ts->monitordestroy[ts->numbermonitors]   = mdestroy;
2343   ts->monitorcontext[ts->numbermonitors++] = (void*)mctx;
2344   PetscFunctionReturn(0);
2345 }
2346 
2347 #undef __FUNCT__
2348 #define __FUNCT__ "TSMonitorCancel"
2349 /*@C
2350    TSMonitorCancel - Clears all the monitors that have been set on a time-step object.
2351 
2352    Logically Collective on TS
2353 
2354    Input Parameters:
2355 .  ts - the TS context obtained from TSCreate()
2356 
2357    Notes:
2358    There is no way to remove a single, specific monitor.
2359 
2360    Level: intermediate
2361 
2362 .keywords: TS, timestep, set, monitor
2363 
2364 .seealso: TSMonitorDefault(), TSMonitorSet()
2365 @*/
2366 PetscErrorCode  TSMonitorCancel(TS ts)
2367 {
2368   PetscErrorCode ierr;
2369   PetscInt       i;
2370 
2371   PetscFunctionBegin;
2372   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2373   for (i=0; i<ts->numbermonitors; i++) {
2374     if (ts->monitordestroy[i]) {
2375       ierr = (*ts->monitordestroy[i])(&ts->monitorcontext[i]);CHKERRQ(ierr);
2376     }
2377   }
2378   ts->numbermonitors = 0;
2379   PetscFunctionReturn(0);
2380 }
2381 
2382 #undef __FUNCT__
2383 #define __FUNCT__ "TSMonitorDefault"
2384 /*@
2385    TSMonitorDefault - Sets the Default monitor
2386 
2387    Level: intermediate
2388 
2389 .keywords: TS, set, monitor
2390 
2391 .seealso: TSMonitorDefault(), TSMonitorSet()
2392 @*/
2393 PetscErrorCode TSMonitorDefault(TS ts,PetscInt step,PetscReal ptime,Vec v,void *dummy)
2394 {
2395   PetscErrorCode ierr;
2396   PetscViewer    viewer = dummy ? (PetscViewer) dummy : PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)ts));
2397 
2398   PetscFunctionBegin;
2399   ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)ts)->tablevel);CHKERRQ(ierr);
2400   ierr = PetscViewerASCIIPrintf(viewer,"%D TS dt %g time %g\n",step,(double)ts->time_step,(double)ptime);CHKERRQ(ierr);
2401   ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)ts)->tablevel);CHKERRQ(ierr);
2402   PetscFunctionReturn(0);
2403 }
2404 
2405 #undef __FUNCT__
2406 #define __FUNCT__ "TSSetRetainStages"
2407 /*@
2408    TSSetRetainStages - Request that all stages in the upcoming step be stored so that interpolation will be available.
2409 
2410    Logically Collective on TS
2411 
2412    Input Argument:
2413 .  ts - time stepping context
2414 
2415    Output Argument:
2416 .  flg - PETSC_TRUE or PETSC_FALSE
2417 
2418    Level: intermediate
2419 
2420 .keywords: TS, set
2421 
2422 .seealso: TSInterpolate(), TSSetPostStep()
2423 @*/
2424 PetscErrorCode TSSetRetainStages(TS ts,PetscBool flg)
2425 {
2426   PetscFunctionBegin;
2427   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2428   ts->retain_stages = flg;
2429   PetscFunctionReturn(0);
2430 }
2431 
2432 #undef __FUNCT__
2433 #define __FUNCT__ "TSInterpolate"
2434 /*@
2435    TSInterpolate - Interpolate the solution computed during the previous step to an arbitrary location in the interval
2436 
2437    Collective on TS
2438 
2439    Input Argument:
2440 +  ts - time stepping context
2441 -  t - time to interpolate to
2442 
2443    Output Argument:
2444 .  U - state at given time
2445 
2446    Notes:
2447    The user should call TSSetRetainStages() before taking a step in which interpolation will be requested.
2448 
2449    Level: intermediate
2450 
2451    Developer Notes:
2452    TSInterpolate() and the storing of previous steps/stages should be generalized to support delay differential equations and continuous adjoints.
2453 
2454 .keywords: TS, set
2455 
2456 .seealso: TSSetRetainStages(), TSSetPostStep()
2457 @*/
2458 PetscErrorCode TSInterpolate(TS ts,PetscReal t,Vec U)
2459 {
2460   PetscErrorCode ierr;
2461 
2462   PetscFunctionBegin;
2463   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2464   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
2465   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,ts->ptime-ts->time_step_prev,ts->ptime);
2466   if (!ts->ops->interpolate) SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"%s does not provide interpolation",((PetscObject)ts)->type_name);
2467   ierr = (*ts->ops->interpolate)(ts,t,U);CHKERRQ(ierr);
2468   PetscFunctionReturn(0);
2469 }
2470 
2471 #undef __FUNCT__
2472 #define __FUNCT__ "TSStep"
2473 /*@
2474    TSStep - Steps one time step
2475 
2476    Collective on TS
2477 
2478    Input Parameter:
2479 .  ts - the TS context obtained from TSCreate()
2480 
2481    Level: intermediate
2482 
2483    Notes:
2484    The hook set using TSSetPreStep() is called before each attempt to take the step. In general, the time step size may
2485    be changed due to adaptive error controller or solve failures. Note that steps may contain multiple stages.
2486 
2487    This may over-step the final time provided in TSSetDuration() depending on the time-step used. TSSolve() interpolates to exactly the
2488    time provided in TSSetDuration(). One can use TSInterpolate() to determine an interpolated solution within the final timestep.
2489 
2490 .keywords: TS, timestep, solve
2491 
2492 .seealso: TSCreate(), TSSetUp(), TSDestroy(), TSSolve(), TSSetPreStep(), TSSetPreStage(), TSInterpolate()
2493 @*/
2494 PetscErrorCode  TSStep(TS ts)
2495 {
2496   PetscReal      ptime_prev;
2497   PetscErrorCode ierr;
2498 
2499   PetscFunctionBegin;
2500   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2501   ierr = TSSetUp(ts);CHKERRQ(ierr);
2502 
2503   ts->reason = TS_CONVERGED_ITERATING;
2504   ptime_prev = ts->ptime;
2505 
2506   ierr = PetscLogEventBegin(TS_Step,ts,0,0,0);CHKERRQ(ierr);
2507   ierr = (*ts->ops->step)(ts);CHKERRQ(ierr);
2508   ierr = PetscLogEventEnd(TS_Step,ts,0,0,0);CHKERRQ(ierr);
2509 
2510   ts->time_step_prev = ts->ptime - ptime_prev;
2511 
2512   if (ts->reason < 0) {
2513     if (ts->errorifstepfailed) {
2514       if (ts->reason == TS_DIVERGED_NONLINEAR_SOLVE) {
2515         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]);
2516       } else SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_NOT_CONVERGED,"TSStep has failed due to %s",TSConvergedReasons[ts->reason]);
2517     }
2518   } else if (!ts->reason) {
2519     if (ts->steps >= ts->max_steps)     ts->reason = TS_CONVERGED_ITS;
2520     else if (ts->ptime >= ts->max_time) ts->reason = TS_CONVERGED_TIME;
2521   }
2522   PetscFunctionReturn(0);
2523 }
2524 
2525 #undef __FUNCT__
2526 #define __FUNCT__ "TSEvaluateStep"
2527 /*@
2528    TSEvaluateStep - Evaluate the solution at the end of a time step with a given order of accuracy.
2529 
2530    Collective on TS
2531 
2532    Input Arguments:
2533 +  ts - time stepping context
2534 .  order - desired order of accuracy
2535 -  done - whether the step was evaluated at this order (pass NULL to generate an error if not available)
2536 
2537    Output Arguments:
2538 .  U - state at the end of the current step
2539 
2540    Level: advanced
2541 
2542    Notes:
2543    This function cannot be called until all stages have been evaluated.
2544    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.
2545 
2546 .seealso: TSStep(), TSAdapt
2547 @*/
2548 PetscErrorCode TSEvaluateStep(TS ts,PetscInt order,Vec U,PetscBool *done)
2549 {
2550   PetscErrorCode ierr;
2551 
2552   PetscFunctionBegin;
2553   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2554   PetscValidType(ts,1);
2555   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
2556   if (!ts->ops->evaluatestep) SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"TSEvaluateStep not implemented for type '%s'",((PetscObject)ts)->type_name);
2557   ierr = (*ts->ops->evaluatestep)(ts,order,U,done);CHKERRQ(ierr);
2558   PetscFunctionReturn(0);
2559 }
2560 
2561 #undef __FUNCT__
2562 #define __FUNCT__ "TSSolve"
2563 /*@
2564    TSSolve - Steps the requested number of timesteps.
2565 
2566    Collective on TS
2567 
2568    Input Parameter:
2569 +  ts - the TS context obtained from TSCreate()
2570 -  u - the solution vector  (can be null if TSSetSolution() was used, otherwise must contain the initial conditions)
2571 
2572    Level: beginner
2573 
2574    Notes:
2575    The final time returned by this function may be different from the time of the internally
2576    held state accessible by TSGetSolution() and TSGetTime() because the method may have
2577    stepped over the final time.
2578 
2579 .keywords: TS, timestep, solve
2580 
2581 .seealso: TSCreate(), TSSetSolution(), TSStep()
2582 @*/
2583 PetscErrorCode TSSolve(TS ts,Vec u)
2584 {
2585   PetscBool         flg;
2586   PetscViewer       viewer;
2587   Vec               solution;
2588   PetscErrorCode    ierr;
2589   PetscViewerFormat format;
2590 
2591   PetscFunctionBegin;
2592   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2593   if (u) PetscValidHeaderSpecific(u,VEC_CLASSID,2);
2594   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 */
2595     PetscValidHeaderSpecific(u,VEC_CLASSID,2);
2596     if (!ts->vec_sol || u == ts->vec_sol) {
2597       ierr = VecDuplicate(u,&solution);CHKERRQ(ierr);
2598       ierr = TSSetSolution(ts,solution);CHKERRQ(ierr);
2599       ierr = VecDestroy(&solution);CHKERRQ(ierr); /* grant ownership */
2600     }
2601     ierr = VecCopy(u,ts->vec_sol);CHKERRQ(ierr);
2602   } else if (u) {
2603     ierr = TSSetSolution(ts,u);CHKERRQ(ierr);
2604   }
2605   ierr = TSSetUp(ts);CHKERRQ(ierr);
2606   /* reset time step and iteration counters */
2607   ts->steps             = 0;
2608   ts->ksp_its           = 0;
2609   ts->snes_its          = 0;
2610   ts->num_snes_failures = 0;
2611   ts->reject            = 0;
2612   ts->reason            = TS_CONVERGED_ITERATING;
2613 
2614   ierr = PetscOptionsGetViewer(PetscObjectComm((PetscObject)ts),((PetscObject)ts)->prefix,"-ts_view_pre",&viewer,&format,&flg);CHKERRQ(ierr);
2615   if (flg && !PetscPreLoadingOn) {
2616     ierr = PetscViewerPushFormat(viewer,format);CHKERRQ(ierr);
2617     ierr = TSView(ts,viewer);CHKERRQ(ierr);
2618     ierr = PetscViewerPopFormat(viewer);CHKERRQ(ierr);
2619     ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
2620   }
2621 
2622   if (ts->ops->solve) {         /* This private interface is transitional and should be removed when all implementations are updated. */
2623     ierr = (*ts->ops->solve)(ts);CHKERRQ(ierr);
2624     ierr = VecCopy(ts->vec_sol,u);CHKERRQ(ierr);
2625     ts->solvetime = ts->ptime;
2626   } else {
2627     /* steps the requested number of timesteps. */
2628     if (ts->steps >= ts->max_steps)     ts->reason = TS_CONVERGED_ITS;
2629     else if (ts->ptime >= ts->max_time) ts->reason = TS_CONVERGED_TIME;
2630     while (!ts->reason) {
2631       ierr = TSMonitor(ts,ts->steps,ts->ptime,ts->vec_sol);CHKERRQ(ierr);
2632       ierr = TSStep(ts);CHKERRQ(ierr);
2633       ierr = TSPostStep(ts);CHKERRQ(ierr);
2634     }
2635     if (ts->exact_final_time == TS_EXACTFINALTIME_INTERPOLATE && ts->ptime > ts->max_time) {
2636       ierr = TSInterpolate(ts,ts->max_time,u);CHKERRQ(ierr);
2637       ts->solvetime = ts->max_time;
2638       solution = u;
2639     } else {
2640       if (u) {ierr = VecCopy(ts->vec_sol,u);CHKERRQ(ierr);}
2641       ts->solvetime = ts->ptime;
2642       solution = ts->vec_sol;
2643     }
2644     ierr = TSMonitor(ts,ts->steps,ts->solvetime,solution);CHKERRQ(ierr);
2645   }
2646   ierr = PetscOptionsGetViewer(PetscObjectComm((PetscObject)ts),((PetscObject)ts)->prefix,"-ts_view",&viewer,&format,&flg);CHKERRQ(ierr);
2647   if (flg && !PetscPreLoadingOn) {
2648     ierr = PetscViewerPushFormat(viewer,format);CHKERRQ(ierr);
2649     ierr = TSView(ts,viewer);CHKERRQ(ierr);
2650     ierr = PetscViewerPopFormat(viewer);CHKERRQ(ierr);
2651     ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
2652   }
2653   PetscFunctionReturn(0);
2654 }
2655 
2656 #undef __FUNCT__
2657 #define __FUNCT__ "TSMonitor"
2658 /*@
2659    TSMonitor - Runs all user-provided monitor routines set using TSMonitorSet()
2660 
2661    Collective on TS
2662 
2663    Input Parameters:
2664 +  ts - time stepping context obtained from TSCreate()
2665 .  step - step number that has just completed
2666 .  ptime - model time of the state
2667 -  u - state at the current model time
2668 
2669    Notes:
2670    TSMonitor() is typically used within the time stepping implementations.
2671    Users might call this function when using the TSStep() interface instead of TSSolve().
2672 
2673    Level: advanced
2674 
2675 .keywords: TS, timestep
2676 @*/
2677 PetscErrorCode TSMonitor(TS ts,PetscInt step,PetscReal ptime,Vec u)
2678 {
2679   PetscErrorCode ierr;
2680   PetscInt       i,n = ts->numbermonitors;
2681 
2682   PetscFunctionBegin;
2683   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2684   PetscValidHeaderSpecific(u,VEC_CLASSID,4);
2685   for (i=0; i<n; i++) {
2686     ierr = (*ts->monitor[i])(ts,step,ptime,u,ts->monitorcontext[i]);CHKERRQ(ierr);
2687   }
2688   PetscFunctionReturn(0);
2689 }
2690 
2691 /* ------------------------------------------------------------------------*/
2692 struct _n_TSMonitorLGCtx {
2693   PetscDrawLG lg;
2694   PetscInt    howoften;  /* when > 0 uses step % howoften, when negative only final solution plotted */
2695   PetscInt    ksp_its,snes_its;
2696 };
2697 
2698 
2699 #undef __FUNCT__
2700 #define __FUNCT__ "TSMonitorLGCtxCreate"
2701 /*@C
2702    TSMonitorLGCtxCreate - Creates a line graph context for use with
2703    TS to monitor the solution process graphically in various ways
2704 
2705    Collective on TS
2706 
2707    Input Parameters:
2708 +  host - the X display to open, or null for the local machine
2709 .  label - the title to put in the title bar
2710 .  x, y - the screen coordinates of the upper left coordinate of the window
2711 .  m, n - the screen width and height in pixels
2712 -  howoften - if positive then determines the frequency of the plotting, if -1 then only at the final time
2713 
2714    Output Parameter:
2715 .  ctx - the context
2716 
2717    Options Database Key:
2718 +  -ts_monitor_lg_timestep - automatically sets line graph monitor
2719 .  -ts_monitor_lg_solution -
2720 .  -ts_monitor_lg_error -
2721 .  -ts_monitor_lg_ksp_iterations -
2722 .  -ts_monitor_lg_snes_iterations -
2723 -  -lg_indicate_data_points <true,false> - indicate the data points (at each time step) on the plot; default is true
2724 
2725    Notes:
2726    Use TSMonitorLGCtxDestroy() to destroy.
2727 
2728    Level: intermediate
2729 
2730 .keywords: TS, monitor, line graph, residual, seealso
2731 
2732 .seealso: TSMonitorLGTimeStep(), TSMonitorSet(), TSMonitorLGSolution(), TSMonitorLGError()
2733 
2734 @*/
2735 PetscErrorCode  TSMonitorLGCtxCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscInt howoften,TSMonitorLGCtx *ctx)
2736 {
2737   PetscDraw      win;
2738   PetscErrorCode ierr;
2739   PetscBool      flg = PETSC_TRUE;
2740 
2741   PetscFunctionBegin;
2742   ierr = PetscNew(struct _n_TSMonitorLGCtx,ctx);CHKERRQ(ierr);
2743   ierr = PetscDrawCreate(comm,host,label,x,y,m,n,&win);CHKERRQ(ierr);
2744   ierr = PetscDrawSetFromOptions(win);CHKERRQ(ierr);
2745   ierr = PetscDrawLGCreate(win,1,&(*ctx)->lg);CHKERRQ(ierr);
2746   ierr = PetscOptionsGetBool(NULL,"-lg_indicate_data_points",&flg,NULL);CHKERRQ(ierr);
2747   if (flg) {
2748     ierr = PetscDrawLGIndicateDataPoints((*ctx)->lg);CHKERRQ(ierr);
2749   }
2750   ierr = PetscLogObjectParent((*ctx)->lg,win);CHKERRQ(ierr);
2751   (*ctx)->howoften = howoften;
2752   PetscFunctionReturn(0);
2753 }
2754 
2755 #undef __FUNCT__
2756 #define __FUNCT__ "TSMonitorLGTimeStep"
2757 PetscErrorCode TSMonitorLGTimeStep(TS ts,PetscInt step,PetscReal ptime,Vec v,void *monctx)
2758 {
2759   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
2760   PetscReal      x   = ptime,y;
2761   PetscErrorCode ierr;
2762 
2763   PetscFunctionBegin;
2764   if (!step) {
2765     PetscDrawAxis axis;
2766     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
2767     ierr = PetscDrawAxisSetLabels(axis,"Timestep as function of time","Time","Time step");CHKERRQ(ierr);
2768     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
2769   }
2770   ierr = TSGetTimeStep(ts,&y);CHKERRQ(ierr);
2771   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
2772   if (((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason)) {
2773     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
2774   }
2775   PetscFunctionReturn(0);
2776 }
2777 
2778 #undef __FUNCT__
2779 #define __FUNCT__ "TSMonitorLGCtxDestroy"
2780 /*@C
2781    TSMonitorLGCtxDestroy - Destroys a line graph context that was created
2782    with TSMonitorLGCtxCreate().
2783 
2784    Collective on TSMonitorLGCtx
2785 
2786    Input Parameter:
2787 .  ctx - the monitor context
2788 
2789    Level: intermediate
2790 
2791 .keywords: TS, monitor, line graph, destroy
2792 
2793 .seealso: TSMonitorLGCtxCreate(),  TSMonitorSet(), TSMonitorLGTimeStep();
2794 @*/
2795 PetscErrorCode  TSMonitorLGCtxDestroy(TSMonitorLGCtx *ctx)
2796 {
2797   PetscDraw      draw;
2798   PetscErrorCode ierr;
2799 
2800   PetscFunctionBegin;
2801   ierr = PetscDrawLGGetDraw((*ctx)->lg,&draw);CHKERRQ(ierr);
2802   ierr = PetscDrawDestroy(&draw);CHKERRQ(ierr);
2803   ierr = PetscDrawLGDestroy(&(*ctx)->lg);CHKERRQ(ierr);
2804   ierr = PetscFree(*ctx);CHKERRQ(ierr);
2805   PetscFunctionReturn(0);
2806 }
2807 
2808 #undef __FUNCT__
2809 #define __FUNCT__ "TSGetTime"
2810 /*@
2811    TSGetTime - Gets the time of the most recently completed step.
2812 
2813    Not Collective
2814 
2815    Input Parameter:
2816 .  ts - the TS context obtained from TSCreate()
2817 
2818    Output Parameter:
2819 .  t  - the current time
2820 
2821    Level: beginner
2822 
2823    Note:
2824    When called during time step evaluation (e.g. during residual evaluation or via hooks set using TSSetPreStep(),
2825    TSSetPreStage(), or TSSetPostStep()), the time is the time at the start of the step being evaluated.
2826 
2827 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
2828 
2829 .keywords: TS, get, time
2830 @*/
2831 PetscErrorCode  TSGetTime(TS ts,PetscReal *t)
2832 {
2833   PetscFunctionBegin;
2834   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2835   PetscValidRealPointer(t,2);
2836   *t = ts->ptime;
2837   PetscFunctionReturn(0);
2838 }
2839 
2840 #undef __FUNCT__
2841 #define __FUNCT__ "TSSetTime"
2842 /*@
2843    TSSetTime - Allows one to reset the time.
2844 
2845    Logically Collective on TS
2846 
2847    Input Parameters:
2848 +  ts - the TS context obtained from TSCreate()
2849 -  time - the time
2850 
2851    Level: intermediate
2852 
2853 .seealso: TSGetTime(), TSSetDuration()
2854 
2855 .keywords: TS, set, time
2856 @*/
2857 PetscErrorCode  TSSetTime(TS ts, PetscReal t)
2858 {
2859   PetscFunctionBegin;
2860   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2861   PetscValidLogicalCollectiveReal(ts,t,2);
2862   ts->ptime = t;
2863   PetscFunctionReturn(0);
2864 }
2865 
2866 #undef __FUNCT__
2867 #define __FUNCT__ "TSSetOptionsPrefix"
2868 /*@C
2869    TSSetOptionsPrefix - Sets the prefix used for searching for all
2870    TS options in the database.
2871 
2872    Logically Collective on TS
2873 
2874    Input Parameter:
2875 +  ts     - The TS context
2876 -  prefix - The prefix to prepend to all option names
2877 
2878    Notes:
2879    A hyphen (-) must NOT be given at the beginning of the prefix name.
2880    The first character of all runtime options is AUTOMATICALLY the
2881    hyphen.
2882 
2883    Level: advanced
2884 
2885 .keywords: TS, set, options, prefix, database
2886 
2887 .seealso: TSSetFromOptions()
2888 
2889 @*/
2890 PetscErrorCode  TSSetOptionsPrefix(TS ts,const char prefix[])
2891 {
2892   PetscErrorCode ierr;
2893   SNES           snes;
2894 
2895   PetscFunctionBegin;
2896   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2897   ierr = PetscObjectSetOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
2898   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2899   ierr = SNESSetOptionsPrefix(snes,prefix);CHKERRQ(ierr);
2900   PetscFunctionReturn(0);
2901 }
2902 
2903 
2904 #undef __FUNCT__
2905 #define __FUNCT__ "TSAppendOptionsPrefix"
2906 /*@C
2907    TSAppendOptionsPrefix - Appends to the prefix used for searching for all
2908    TS options in the database.
2909 
2910    Logically Collective on TS
2911 
2912    Input Parameter:
2913 +  ts     - The TS context
2914 -  prefix - The prefix to prepend to all option names
2915 
2916    Notes:
2917    A hyphen (-) must NOT be given at the beginning of the prefix name.
2918    The first character of all runtime options is AUTOMATICALLY the
2919    hyphen.
2920 
2921    Level: advanced
2922 
2923 .keywords: TS, append, options, prefix, database
2924 
2925 .seealso: TSGetOptionsPrefix()
2926 
2927 @*/
2928 PetscErrorCode  TSAppendOptionsPrefix(TS ts,const char prefix[])
2929 {
2930   PetscErrorCode ierr;
2931   SNES           snes;
2932 
2933   PetscFunctionBegin;
2934   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2935   ierr = PetscObjectAppendOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
2936   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2937   ierr = SNESAppendOptionsPrefix(snes,prefix);CHKERRQ(ierr);
2938   PetscFunctionReturn(0);
2939 }
2940 
2941 #undef __FUNCT__
2942 #define __FUNCT__ "TSGetOptionsPrefix"
2943 /*@C
2944    TSGetOptionsPrefix - Sets the prefix used for searching for all
2945    TS options in the database.
2946 
2947    Not Collective
2948 
2949    Input Parameter:
2950 .  ts - The TS context
2951 
2952    Output Parameter:
2953 .  prefix - A pointer to the prefix string used
2954 
2955    Notes: On the fortran side, the user should pass in a string 'prifix' of
2956    sufficient length to hold the prefix.
2957 
2958    Level: intermediate
2959 
2960 .keywords: TS, get, options, prefix, database
2961 
2962 .seealso: TSAppendOptionsPrefix()
2963 @*/
2964 PetscErrorCode  TSGetOptionsPrefix(TS ts,const char *prefix[])
2965 {
2966   PetscErrorCode ierr;
2967 
2968   PetscFunctionBegin;
2969   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2970   PetscValidPointer(prefix,2);
2971   ierr = PetscObjectGetOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
2972   PetscFunctionReturn(0);
2973 }
2974 
2975 #undef __FUNCT__
2976 #define __FUNCT__ "TSGetRHSJacobian"
2977 /*@C
2978    TSGetRHSJacobian - Returns the Jacobian J at the present timestep.
2979 
2980    Not Collective, but parallel objects are returned if TS is parallel
2981 
2982    Input Parameter:
2983 .  ts  - The TS context obtained from TSCreate()
2984 
2985    Output Parameters:
2986 +  Amat - The (approximate) Jacobian J of G, where U_t = G(U,t)  (or NULL)
2987 .  Pmat - The matrix from which the preconditioner is constructed, usually the same as Amat  (or NULL)
2988 .  func - Function to compute the Jacobian of the RHS  (or NULL)
2989 -  ctx - User-defined context for Jacobian evaluation routine  (or NULL)
2990 
2991    Notes: You can pass in NULL for any return argument you do not need.
2992 
2993    Level: intermediate
2994 
2995 .seealso: TSGetTimeStep(), TSGetMatrices(), TSGetTime(), TSGetTimeStepNumber()
2996 
2997 .keywords: TS, timestep, get, matrix, Jacobian
2998 @*/
2999 PetscErrorCode  TSGetRHSJacobian(TS ts,Mat *Amat,Mat *Pmat,TSRHSJacobian *func,void **ctx)
3000 {
3001   PetscErrorCode ierr;
3002   SNES           snes;
3003   DM             dm;
3004 
3005   PetscFunctionBegin;
3006   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3007   ierr = SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);CHKERRQ(ierr);
3008   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
3009   ierr = DMTSGetRHSJacobian(dm,func,ctx);CHKERRQ(ierr);
3010   PetscFunctionReturn(0);
3011 }
3012 
3013 #undef __FUNCT__
3014 #define __FUNCT__ "TSGetIJacobian"
3015 /*@C
3016    TSGetIJacobian - Returns the implicit Jacobian at the present timestep.
3017 
3018    Not Collective, but parallel objects are returned if TS is parallel
3019 
3020    Input Parameter:
3021 .  ts  - The TS context obtained from TSCreate()
3022 
3023    Output Parameters:
3024 +  Amat  - The (approximate) Jacobian of F(t,U,U_t)
3025 .  Pmat - The matrix from which the preconditioner is constructed, often the same as Amat
3026 .  f   - The function to compute the matrices
3027 - ctx - User-defined context for Jacobian evaluation routine
3028 
3029    Notes: You can pass in NULL for any return argument you do not need.
3030 
3031    Level: advanced
3032 
3033 .seealso: TSGetTimeStep(), TSGetRHSJacobian(), TSGetMatrices(), TSGetTime(), TSGetTimeStepNumber()
3034 
3035 .keywords: TS, timestep, get, matrix, Jacobian
3036 @*/
3037 PetscErrorCode  TSGetIJacobian(TS ts,Mat *Amat,Mat *Pmat,TSIJacobian *f,void **ctx)
3038 {
3039   PetscErrorCode ierr;
3040   SNES           snes;
3041   DM             dm;
3042 
3043   PetscFunctionBegin;
3044   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3045   ierr = SNESSetUpMatrices(snes);CHKERRQ(ierr);
3046   ierr = SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);CHKERRQ(ierr);
3047   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
3048   ierr = DMTSGetIJacobian(dm,f,ctx);CHKERRQ(ierr);
3049   PetscFunctionReturn(0);
3050 }
3051 
3052 
3053 #undef __FUNCT__
3054 #define __FUNCT__ "TSMonitorDrawSolution"
3055 /*@C
3056    TSMonitorDrawSolution - Monitors progress of the TS solvers by calling
3057    VecView() for the solution at each timestep
3058 
3059    Collective on TS
3060 
3061    Input Parameters:
3062 +  ts - the TS context
3063 .  step - current time-step
3064 .  ptime - current time
3065 -  dummy - either a viewer or NULL
3066 
3067    Options Database:
3068 .   -ts_monitor_draw_solution_initial - show initial solution as well as current solution
3069 
3070    Notes: the initial solution and current solution are not displayed with a common axis scaling so generally the option -ts_monitor_draw_solution_initial
3071        will look bad
3072 
3073    Level: intermediate
3074 
3075 .keywords: TS,  vector, monitor, view
3076 
3077 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3078 @*/
3079 PetscErrorCode  TSMonitorDrawSolution(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
3080 {
3081   PetscErrorCode   ierr;
3082   TSMonitorDrawCtx ictx = (TSMonitorDrawCtx)dummy;
3083   PetscDraw        draw;
3084 
3085   PetscFunctionBegin;
3086   if (!step && ictx->showinitial) {
3087     if (!ictx->initialsolution) {
3088       ierr = VecDuplicate(u,&ictx->initialsolution);CHKERRQ(ierr);
3089     }
3090     ierr = VecCopy(u,ictx->initialsolution);CHKERRQ(ierr);
3091   }
3092   if (!(((ictx->howoften > 0) && (!(step % ictx->howoften))) || ((ictx->howoften == -1) && ts->reason))) PetscFunctionReturn(0);
3093 
3094   if (ictx->showinitial) {
3095     PetscReal pause;
3096     ierr = PetscViewerDrawGetPause(ictx->viewer,&pause);CHKERRQ(ierr);
3097     ierr = PetscViewerDrawSetPause(ictx->viewer,0.0);CHKERRQ(ierr);
3098     ierr = VecView(ictx->initialsolution,ictx->viewer);CHKERRQ(ierr);
3099     ierr = PetscViewerDrawSetPause(ictx->viewer,pause);CHKERRQ(ierr);
3100     ierr = PetscViewerDrawSetHold(ictx->viewer,PETSC_TRUE);CHKERRQ(ierr);
3101   }
3102   ierr = VecView(u,ictx->viewer);CHKERRQ(ierr);
3103   if (ictx->showtimestepandtime) {
3104     PetscReal xl,yl,xr,yr,tw,w,h;
3105     char      time[32];
3106     size_t    len;
3107 
3108     ierr = PetscViewerDrawGetDraw(ictx->viewer,0,&draw);CHKERRQ(ierr);
3109     ierr = PetscSNPrintf(time,32,"Timestep %d Time %f",(int)step,(double)ptime);CHKERRQ(ierr);
3110     ierr = PetscDrawGetCoordinates(draw,&xl,&yl,&xr,&yr);CHKERRQ(ierr);
3111     ierr =  PetscStrlen(time,&len);CHKERRQ(ierr);
3112     ierr = PetscDrawStringGetSize(draw,&tw,NULL);CHKERRQ(ierr);
3113     w    = xl + .5*(xr - xl) - .5*len*tw;
3114     h    = yl + .95*(yr - yl);
3115     ierr = PetscDrawString(draw,w,h,PETSC_DRAW_BLACK,time);CHKERRQ(ierr);
3116     ierr = PetscDrawFlush(draw);CHKERRQ(ierr);
3117   }
3118 
3119   if (ictx->showinitial) {
3120     ierr = PetscViewerDrawSetHold(ictx->viewer,PETSC_FALSE);CHKERRQ(ierr);
3121   }
3122   PetscFunctionReturn(0);
3123 }
3124 
3125 #undef __FUNCT__
3126 #define __FUNCT__ "TSMonitorDrawSolutionPhase"
3127 /*@C
3128    TSMonitorDrawSolutionPhase - Monitors progress of the TS solvers by plotting the solution as a phase diagram
3129 
3130    Collective on TS
3131 
3132    Input Parameters:
3133 +  ts - the TS context
3134 .  step - current time-step
3135 .  ptime - current time
3136 -  dummy - either a viewer or NULL
3137 
3138    Level: intermediate
3139 
3140 .keywords: TS,  vector, monitor, view
3141 
3142 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3143 @*/
3144 PetscErrorCode  TSMonitorDrawSolutionPhase(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
3145 {
3146   PetscErrorCode    ierr;
3147   TSMonitorDrawCtx  ictx = (TSMonitorDrawCtx)dummy;
3148   PetscDraw         draw;
3149   MPI_Comm          comm;
3150   PetscInt          n;
3151   PetscMPIInt       size;
3152   PetscReal         xl,yl,xr,yr,tw,w,h;
3153   char              time[32];
3154   size_t            len;
3155   const PetscScalar *U;
3156 
3157   PetscFunctionBegin;
3158   ierr = PetscObjectGetComm((PetscObject)ts,&comm);CHKERRQ(ierr);
3159   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
3160   if (size != 1) SETERRQ(comm,PETSC_ERR_SUP,"Only allowed for sequential runs");
3161   ierr = VecGetSize(u,&n);CHKERRQ(ierr);
3162   if (n != 2) SETERRQ(comm,PETSC_ERR_SUP,"Only for ODEs with two unknowns");
3163 
3164   ierr = PetscViewerDrawGetDraw(ictx->viewer,0,&draw);CHKERRQ(ierr);
3165 
3166   ierr = VecGetArrayRead(u,&U);CHKERRQ(ierr);
3167   ierr = PetscDrawAxisGetLimits(ictx->axis,&xl,&xr,&yl,&yr);CHKERRQ(ierr);
3168   if ((PetscRealPart(U[0]) < xl) || (PetscRealPart(U[1]) < yl) || (PetscRealPart(U[0]) > xr) || (PetscRealPart(U[1]) > yr)) {
3169       ierr = VecRestoreArrayRead(u,&U);CHKERRQ(ierr);
3170       PetscFunctionReturn(0);
3171   }
3172   if (!step) ictx->color++;
3173   ierr = PetscDrawPoint(draw,PetscRealPart(U[0]),PetscRealPart(U[1]),ictx->color);CHKERRQ(ierr);
3174   ierr = VecRestoreArrayRead(u,&U);CHKERRQ(ierr);
3175 
3176   if (ictx->showtimestepandtime) {
3177     ierr = PetscDrawGetCoordinates(draw,&xl,&yl,&xr,&yr);CHKERRQ(ierr);
3178     ierr = PetscSNPrintf(time,32,"Timestep %d Time %f",(int)step,(double)ptime);CHKERRQ(ierr);
3179     ierr = PetscStrlen(time,&len);CHKERRQ(ierr);
3180     ierr = PetscDrawStringGetSize(draw,&tw,NULL);CHKERRQ(ierr);
3181     w    = xl + .5*(xr - xl) - .5*len*tw;
3182     h    = yl + .95*(yr - yl);
3183     ierr = PetscDrawString(draw,w,h,PETSC_DRAW_BLACK,time);CHKERRQ(ierr);
3184   }
3185   ierr = PetscDrawFlush(draw);CHKERRQ(ierr);
3186   PetscFunctionReturn(0);
3187 }
3188 
3189 
3190 #undef __FUNCT__
3191 #define __FUNCT__ "TSMonitorDrawCtxDestroy"
3192 /*@C
3193    TSMonitorDrawCtxDestroy - Destroys the monitor context for TSMonitorDrawSolution()
3194 
3195    Collective on TS
3196 
3197    Input Parameters:
3198 .    ctx - the monitor context
3199 
3200    Level: intermediate
3201 
3202 .keywords: TS,  vector, monitor, view
3203 
3204 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSMonitorDrawSolution(), TSMonitorDrawError()
3205 @*/
3206 PetscErrorCode  TSMonitorDrawCtxDestroy(TSMonitorDrawCtx *ictx)
3207 {
3208   PetscErrorCode ierr;
3209 
3210   PetscFunctionBegin;
3211   ierr = PetscDrawAxisDestroy(&(*ictx)->axis);CHKERRQ(ierr);
3212   ierr = PetscViewerDestroy(&(*ictx)->viewer);CHKERRQ(ierr);
3213   ierr = VecDestroy(&(*ictx)->initialsolution);CHKERRQ(ierr);
3214   ierr = PetscFree(*ictx);CHKERRQ(ierr);
3215   PetscFunctionReturn(0);
3216 }
3217 
3218 #undef __FUNCT__
3219 #define __FUNCT__ "TSMonitorDrawCtxCreate"
3220 /*@C
3221    TSMonitorDrawCtxCreate - Creates the monitor context for TSMonitorDrawCtx
3222 
3223    Collective on TS
3224 
3225    Input Parameter:
3226 .    ts - time-step context
3227 
3228    Output Patameter:
3229 .    ctx - the monitor context
3230 
3231    Options Database:
3232 .   -ts_monitor_draw_solution_initial - show initial solution as well as current solution
3233 
3234    Level: intermediate
3235 
3236 .keywords: TS,  vector, monitor, view
3237 
3238 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSMonitorDrawCtx()
3239 @*/
3240 PetscErrorCode  TSMonitorDrawCtxCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscInt howoften,TSMonitorDrawCtx *ctx)
3241 {
3242   PetscErrorCode   ierr;
3243 
3244   PetscFunctionBegin;
3245   ierr = PetscNew(struct _n_TSMonitorDrawCtx,ctx);CHKERRQ(ierr);
3246   ierr = PetscViewerDrawOpen(comm,host,label,x,y,m,n,&(*ctx)->viewer);CHKERRQ(ierr);
3247   ierr = PetscViewerSetFromOptions((*ctx)->viewer);CHKERRQ(ierr);
3248 
3249   (*ctx)->howoften    = howoften;
3250   (*ctx)->showinitial = PETSC_FALSE;
3251   ierr = PetscOptionsGetBool(NULL,"-ts_monitor_draw_solution_initial",&(*ctx)->showinitial,NULL);CHKERRQ(ierr);
3252 
3253   (*ctx)->showtimestepandtime = PETSC_FALSE;
3254   ierr = PetscOptionsGetBool(NULL,"-ts_monitor_draw_solution_show_time",&(*ctx)->showtimestepandtime,NULL);CHKERRQ(ierr);
3255   (*ctx)->color = PETSC_DRAW_WHITE;
3256   PetscFunctionReturn(0);
3257 }
3258 
3259 #undef __FUNCT__
3260 #define __FUNCT__ "TSMonitorDrawError"
3261 /*@C
3262    TSMonitorDrawError - Monitors progress of the TS solvers by calling
3263    VecView() for the error at each timestep
3264 
3265    Collective on TS
3266 
3267    Input Parameters:
3268 +  ts - the TS context
3269 .  step - current time-step
3270 .  ptime - current time
3271 -  dummy - either a viewer or NULL
3272 
3273    Level: intermediate
3274 
3275 .keywords: TS,  vector, monitor, view
3276 
3277 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3278 @*/
3279 PetscErrorCode  TSMonitorDrawError(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
3280 {
3281   PetscErrorCode   ierr;
3282   TSMonitorDrawCtx ctx    = (TSMonitorDrawCtx)dummy;
3283   PetscViewer      viewer = ctx->viewer;
3284   Vec              work;
3285 
3286   PetscFunctionBegin;
3287   if (!(((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason))) PetscFunctionReturn(0);
3288   ierr = VecDuplicate(u,&work);CHKERRQ(ierr);
3289   ierr = TSComputeSolutionFunction(ts,ptime,work);CHKERRQ(ierr);
3290   ierr = VecAXPY(work,-1.0,u);CHKERRQ(ierr);
3291   ierr = VecView(work,viewer);CHKERRQ(ierr);
3292   ierr = VecDestroy(&work);CHKERRQ(ierr);
3293   PetscFunctionReturn(0);
3294 }
3295 
3296 #include <petsc-private/dmimpl.h>
3297 #undef __FUNCT__
3298 #define __FUNCT__ "TSSetDM"
3299 /*@
3300    TSSetDM - Sets the DM that may be used by some preconditioners
3301 
3302    Logically Collective on TS and DM
3303 
3304    Input Parameters:
3305 +  ts - the preconditioner context
3306 -  dm - the dm
3307 
3308    Level: intermediate
3309 
3310 
3311 .seealso: TSGetDM(), SNESSetDM(), SNESGetDM()
3312 @*/
3313 PetscErrorCode  TSSetDM(TS ts,DM dm)
3314 {
3315   PetscErrorCode ierr;
3316   SNES           snes;
3317   DMTS           tsdm;
3318 
3319   PetscFunctionBegin;
3320   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3321   ierr = PetscObjectReference((PetscObject)dm);CHKERRQ(ierr);
3322   if (ts->dm) {               /* Move the DMTS context over to the new DM unless the new DM already has one */
3323     if (ts->dm->dmts && !dm->dmts) {
3324       ierr = DMCopyDMTS(ts->dm,dm);CHKERRQ(ierr);
3325       ierr = DMGetDMTS(ts->dm,&tsdm);CHKERRQ(ierr);
3326       if (tsdm->originaldm == ts->dm) { /* Grant write privileges to the replacement DM */
3327         tsdm->originaldm = dm;
3328       }
3329     }
3330     ierr = DMDestroy(&ts->dm);CHKERRQ(ierr);
3331   }
3332   ts->dm = dm;
3333 
3334   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3335   ierr = SNESSetDM(snes,dm);CHKERRQ(ierr);
3336   PetscFunctionReturn(0);
3337 }
3338 
3339 #undef __FUNCT__
3340 #define __FUNCT__ "TSGetDM"
3341 /*@
3342    TSGetDM - Gets the DM that may be used by some preconditioners
3343 
3344    Not Collective
3345 
3346    Input Parameter:
3347 . ts - the preconditioner context
3348 
3349    Output Parameter:
3350 .  dm - the dm
3351 
3352    Level: intermediate
3353 
3354 
3355 .seealso: TSSetDM(), SNESSetDM(), SNESGetDM()
3356 @*/
3357 PetscErrorCode  TSGetDM(TS ts,DM *dm)
3358 {
3359   PetscErrorCode ierr;
3360 
3361   PetscFunctionBegin;
3362   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3363   if (!ts->dm) {
3364     ierr = DMShellCreate(PetscObjectComm((PetscObject)ts),&ts->dm);CHKERRQ(ierr);
3365     if (ts->snes) {ierr = SNESSetDM(ts->snes,ts->dm);CHKERRQ(ierr);}
3366   }
3367   *dm = ts->dm;
3368   PetscFunctionReturn(0);
3369 }
3370 
3371 #undef __FUNCT__
3372 #define __FUNCT__ "SNESTSFormFunction"
3373 /*@
3374    SNESTSFormFunction - Function to evaluate nonlinear residual
3375 
3376    Logically Collective on SNES
3377 
3378    Input Parameter:
3379 + snes - nonlinear solver
3380 . U - the current state at which to evaluate the residual
3381 - ctx - user context, must be a TS
3382 
3383    Output Parameter:
3384 . F - the nonlinear residual
3385 
3386    Notes:
3387    This function is not normally called by users and is automatically registered with the SNES used by TS.
3388    It is most frequently passed to MatFDColoringSetFunction().
3389 
3390    Level: advanced
3391 
3392 .seealso: SNESSetFunction(), MatFDColoringSetFunction()
3393 @*/
3394 PetscErrorCode  SNESTSFormFunction(SNES snes,Vec U,Vec F,void *ctx)
3395 {
3396   TS             ts = (TS)ctx;
3397   PetscErrorCode ierr;
3398 
3399   PetscFunctionBegin;
3400   PetscValidHeaderSpecific(snes,SNES_CLASSID,1);
3401   PetscValidHeaderSpecific(U,VEC_CLASSID,2);
3402   PetscValidHeaderSpecific(F,VEC_CLASSID,3);
3403   PetscValidHeaderSpecific(ts,TS_CLASSID,4);
3404   ierr = (ts->ops->snesfunction)(snes,U,F,ts);CHKERRQ(ierr);
3405   PetscFunctionReturn(0);
3406 }
3407 
3408 #undef __FUNCT__
3409 #define __FUNCT__ "SNESTSFormJacobian"
3410 /*@
3411    SNESTSFormJacobian - Function to evaluate the Jacobian
3412 
3413    Collective on SNES
3414 
3415    Input Parameter:
3416 + snes - nonlinear solver
3417 . U - the current state at which to evaluate the residual
3418 - ctx - user context, must be a TS
3419 
3420    Output Parameter:
3421 + A - the Jacobian
3422 . B - the preconditioning matrix (may be the same as A)
3423 - flag - indicates any structure change in the matrix
3424 
3425    Notes:
3426    This function is not normally called by users and is automatically registered with the SNES used by TS.
3427 
3428    Level: developer
3429 
3430 .seealso: SNESSetJacobian()
3431 @*/
3432 PetscErrorCode  SNESTSFormJacobian(SNES snes,Vec U,Mat *A,Mat *B,MatStructure *flag,void *ctx)
3433 {
3434   TS             ts = (TS)ctx;
3435   PetscErrorCode ierr;
3436 
3437   PetscFunctionBegin;
3438   PetscValidHeaderSpecific(snes,SNES_CLASSID,1);
3439   PetscValidHeaderSpecific(U,VEC_CLASSID,2);
3440   PetscValidPointer(A,3);
3441   PetscValidHeaderSpecific(*A,MAT_CLASSID,3);
3442   PetscValidPointer(B,4);
3443   PetscValidHeaderSpecific(*B,MAT_CLASSID,4);
3444   PetscValidPointer(flag,5);
3445   PetscValidHeaderSpecific(ts,TS_CLASSID,6);
3446   ierr = (ts->ops->snesjacobian)(snes,U,A,B,flag,ts);CHKERRQ(ierr);
3447   PetscFunctionReturn(0);
3448 }
3449 
3450 #undef __FUNCT__
3451 #define __FUNCT__ "TSComputeRHSFunctionLinear"
3452 /*@C
3453    TSComputeRHSFunctionLinear - Evaluate the right hand side via the user-provided Jacobian, for linear problems only
3454 
3455    Collective on TS
3456 
3457    Input Arguments:
3458 +  ts - time stepping context
3459 .  t - time at which to evaluate
3460 .  U - state at which to evaluate
3461 -  ctx - context
3462 
3463    Output Arguments:
3464 .  F - right hand side
3465 
3466    Level: intermediate
3467 
3468    Notes:
3469    This function is intended to be passed to TSSetRHSFunction() to evaluate the right hand side for linear problems.
3470    The matrix (and optionally the evaluation context) should be passed to TSSetRHSJacobian().
3471 
3472 .seealso: TSSetRHSFunction(), TSSetRHSJacobian(), TSComputeRHSJacobianConstant()
3473 @*/
3474 PetscErrorCode TSComputeRHSFunctionLinear(TS ts,PetscReal t,Vec U,Vec F,void *ctx)
3475 {
3476   PetscErrorCode ierr;
3477   Mat            Arhs,Brhs;
3478   MatStructure   flg2;
3479 
3480   PetscFunctionBegin;
3481   ierr = TSGetRHSMats_Private(ts,&Arhs,&Brhs);CHKERRQ(ierr);
3482   ierr = TSComputeRHSJacobian(ts,t,U,&Arhs,&Brhs,&flg2);CHKERRQ(ierr);
3483   ierr = MatMult(Arhs,U,F);CHKERRQ(ierr);
3484   PetscFunctionReturn(0);
3485 }
3486 
3487 #undef __FUNCT__
3488 #define __FUNCT__ "TSComputeRHSJacobianConstant"
3489 /*@C
3490    TSComputeRHSJacobianConstant - Reuses a Jacobian that is time-independent.
3491 
3492    Collective on TS
3493 
3494    Input Arguments:
3495 +  ts - time stepping context
3496 .  t - time at which to evaluate
3497 .  U - state at which to evaluate
3498 -  ctx - context
3499 
3500    Output Arguments:
3501 +  A - pointer to operator
3502 .  B - pointer to preconditioning matrix
3503 -  flg - matrix structure flag
3504 
3505    Level: intermediate
3506 
3507    Notes:
3508    This function is intended to be passed to TSSetRHSJacobian() to evaluate the Jacobian for linear time-independent problems.
3509 
3510 .seealso: TSSetRHSFunction(), TSSetRHSJacobian(), TSComputeRHSFunctionLinear()
3511 @*/
3512 PetscErrorCode TSComputeRHSJacobianConstant(TS ts,PetscReal t,Vec U,Mat *A,Mat *B,MatStructure *flg,void *ctx)
3513 {
3514   PetscFunctionBegin;
3515   *flg = SAME_PRECONDITIONER;
3516   PetscFunctionReturn(0);
3517 }
3518 
3519 #undef __FUNCT__
3520 #define __FUNCT__ "TSComputeIFunctionLinear"
3521 /*@C
3522    TSComputeIFunctionLinear - Evaluate the left hand side via the user-provided Jacobian, for linear problems only
3523 
3524    Collective on TS
3525 
3526    Input Arguments:
3527 +  ts - time stepping context
3528 .  t - time at which to evaluate
3529 .  U - state at which to evaluate
3530 .  Udot - time derivative of state vector
3531 -  ctx - context
3532 
3533    Output Arguments:
3534 .  F - left hand side
3535 
3536    Level: intermediate
3537 
3538    Notes:
3539    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
3540    user is required to write their own TSComputeIFunction.
3541    This function is intended to be passed to TSSetIFunction() to evaluate the left hand side for linear problems.
3542    The matrix (and optionally the evaluation context) should be passed to TSSetIJacobian().
3543 
3544 .seealso: TSSetIFunction(), TSSetIJacobian(), TSComputeIJacobianConstant()
3545 @*/
3546 PetscErrorCode TSComputeIFunctionLinear(TS ts,PetscReal t,Vec U,Vec Udot,Vec F,void *ctx)
3547 {
3548   PetscErrorCode ierr;
3549   Mat            A,B;
3550   MatStructure   flg2;
3551 
3552   PetscFunctionBegin;
3553   ierr = TSGetIJacobian(ts,&A,&B,NULL,NULL);CHKERRQ(ierr);
3554   ierr = TSComputeIJacobian(ts,t,U,Udot,1.0,&A,&B,&flg2,PETSC_TRUE);CHKERRQ(ierr);
3555   ierr = MatMult(A,Udot,F);CHKERRQ(ierr);
3556   PetscFunctionReturn(0);
3557 }
3558 
3559 #undef __FUNCT__
3560 #define __FUNCT__ "TSComputeIJacobianConstant"
3561 /*@C
3562    TSComputeIJacobianConstant - Reuses a time-independent for a semi-implicit DAE or ODE
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 .  Udot - time derivative of state vector
3571 .  shift - shift to apply
3572 -  ctx - context
3573 
3574    Output Arguments:
3575 +  A - pointer to operator
3576 .  B - pointer to preconditioning matrix
3577 -  flg - matrix structure flag
3578 
3579    Level: advanced
3580 
3581    Notes:
3582    This function is intended to be passed to TSSetIJacobian() to evaluate the Jacobian for linear time-independent problems.
3583 
3584    It is only appropriate for problems of the form
3585 
3586 $     M Udot = F(U,t)
3587 
3588   where M is constant and F is non-stiff.  The user must pass M to TSSetIJacobian().  The current implementation only
3589   works with IMEX time integration methods such as TSROSW and TSARKIMEX, since there is no support for de-constructing
3590   an implicit operator of the form
3591 
3592 $    shift*M + J
3593 
3594   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
3595   a copy of M or reassemble it when requested.
3596 
3597 .seealso: TSSetIFunction(), TSSetIJacobian(), TSComputeIFunctionLinear()
3598 @*/
3599 PetscErrorCode TSComputeIJacobianConstant(TS ts,PetscReal t,Vec U,Vec Udot,PetscReal shift,Mat *A,Mat *B,MatStructure *flg,void *ctx)
3600 {
3601   PetscErrorCode ierr;
3602 
3603   PetscFunctionBegin;
3604   ierr = MatScale(*A, shift / ts->ijacobian.shift);CHKERRQ(ierr);
3605   ts->ijacobian.shift = shift;
3606   *flg = SAME_PRECONDITIONER;
3607   PetscFunctionReturn(0);
3608 }
3609 
3610 #undef __FUNCT__
3611 #define __FUNCT__ "TSGetEquationType"
3612 /*@
3613    TSGetEquationType - Gets the type of the equation that TS is solving.
3614 
3615    Not Collective
3616 
3617    Input Parameter:
3618 .  ts - the TS context
3619 
3620    Output Parameter:
3621 .  equation_type - see TSEquationType
3622 
3623    Level: beginner
3624 
3625 .keywords: TS, equation type
3626 
3627 .seealso: TSSetEquationType(), TSEquationType
3628 @*/
3629 PetscErrorCode  TSGetEquationType(TS ts,TSEquationType *equation_type)
3630 {
3631   PetscFunctionBegin;
3632   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3633   PetscValidPointer(equation_type,2);
3634   *equation_type = ts->equation_type;
3635   PetscFunctionReturn(0);
3636 }
3637 
3638 #undef __FUNCT__
3639 #define __FUNCT__ "TSSetEquationType"
3640 /*@
3641    TSSetEquationType - Sets the type of the equation that TS is solving.
3642 
3643    Not Collective
3644 
3645    Input Parameter:
3646 +  ts - the TS context
3647 .  equation_type - see TSEquationType
3648 
3649    Level: advanced
3650 
3651 .keywords: TS, equation type
3652 
3653 .seealso: TSGetEquationType(), TSEquationType
3654 @*/
3655 PetscErrorCode  TSSetEquationType(TS ts,TSEquationType equation_type)
3656 {
3657   PetscFunctionBegin;
3658   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3659   ts->equation_type = equation_type;
3660   PetscFunctionReturn(0);
3661 }
3662 
3663 #undef __FUNCT__
3664 #define __FUNCT__ "TSGetConvergedReason"
3665 /*@
3666    TSGetConvergedReason - Gets the reason the TS iteration was stopped.
3667 
3668    Not Collective
3669 
3670    Input Parameter:
3671 .  ts - the TS context
3672 
3673    Output Parameter:
3674 .  reason - negative value indicates diverged, positive value converged, see TSConvergedReason or the
3675             manual pages for the individual convergence tests for complete lists
3676 
3677    Level: beginner
3678 
3679    Notes:
3680    Can only be called after the call to TSSolve() is complete.
3681 
3682 .keywords: TS, nonlinear, set, convergence, test
3683 
3684 .seealso: TSSetConvergenceTest(), TSConvergedReason
3685 @*/
3686 PetscErrorCode  TSGetConvergedReason(TS ts,TSConvergedReason *reason)
3687 {
3688   PetscFunctionBegin;
3689   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3690   PetscValidPointer(reason,2);
3691   *reason = ts->reason;
3692   PetscFunctionReturn(0);
3693 }
3694 
3695 #undef __FUNCT__
3696 #define __FUNCT__ "TSSetConvergedReason"
3697 /*@
3698    TSSetConvergedReason - Sets the reason for handling the convergence of TSSolve.
3699 
3700    Not Collective
3701 
3702    Input Parameter:
3703 +  ts - the TS context
3704 .  reason - negative value indicates diverged, positive value converged, see TSConvergedReason or the
3705             manual pages for the individual convergence tests for complete lists
3706 
3707    Level: advanced
3708 
3709    Notes:
3710    Can only be called during TSSolve() is active.
3711 
3712 .keywords: TS, nonlinear, set, convergence, test
3713 
3714 .seealso: TSConvergedReason
3715 @*/
3716 PetscErrorCode  TSSetConvergedReason(TS ts,TSConvergedReason reason)
3717 {
3718   PetscFunctionBegin;
3719   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3720   ts->reason = reason;
3721   PetscFunctionReturn(0);
3722 }
3723 
3724 #undef __FUNCT__
3725 #define __FUNCT__ "TSGetSolveTime"
3726 /*@
3727    TSGetSolveTime - Gets the time after a call to TSSolve()
3728 
3729    Not Collective
3730 
3731    Input Parameter:
3732 .  ts - the TS context
3733 
3734    Output Parameter:
3735 .  ftime - the final time. This time should correspond to the final time set with TSSetDuration()
3736 
3737    Level: beginner
3738 
3739    Notes:
3740    Can only be called after the call to TSSolve() is complete.
3741 
3742 .keywords: TS, nonlinear, set, convergence, test
3743 
3744 .seealso: TSSetConvergenceTest(), TSConvergedReason
3745 @*/
3746 PetscErrorCode  TSGetSolveTime(TS ts,PetscReal *ftime)
3747 {
3748   PetscFunctionBegin;
3749   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3750   PetscValidPointer(ftime,2);
3751   *ftime = ts->solvetime;
3752   PetscFunctionReturn(0);
3753 }
3754 
3755 #undef __FUNCT__
3756 #define __FUNCT__ "TSGetSNESIterations"
3757 /*@
3758    TSGetSNESIterations - Gets the total number of nonlinear iterations
3759    used by the time integrator.
3760 
3761    Not Collective
3762 
3763    Input Parameter:
3764 .  ts - TS context
3765 
3766    Output Parameter:
3767 .  nits - number of nonlinear iterations
3768 
3769    Notes:
3770    This counter is reset to zero for each successive call to TSSolve().
3771 
3772    Level: intermediate
3773 
3774 .keywords: TS, get, number, nonlinear, iterations
3775 
3776 .seealso:  TSGetKSPIterations()
3777 @*/
3778 PetscErrorCode TSGetSNESIterations(TS ts,PetscInt *nits)
3779 {
3780   PetscFunctionBegin;
3781   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3782   PetscValidIntPointer(nits,2);
3783   *nits = ts->snes_its;
3784   PetscFunctionReturn(0);
3785 }
3786 
3787 #undef __FUNCT__
3788 #define __FUNCT__ "TSGetKSPIterations"
3789 /*@
3790    TSGetKSPIterations - Gets the total number of linear iterations
3791    used by the time integrator.
3792 
3793    Not Collective
3794 
3795    Input Parameter:
3796 .  ts - TS context
3797 
3798    Output Parameter:
3799 .  lits - number of linear iterations
3800 
3801    Notes:
3802    This counter is reset to zero for each successive call to TSSolve().
3803 
3804    Level: intermediate
3805 
3806 .keywords: TS, get, number, linear, iterations
3807 
3808 .seealso:  TSGetSNESIterations(), SNESGetKSPIterations()
3809 @*/
3810 PetscErrorCode TSGetKSPIterations(TS ts,PetscInt *lits)
3811 {
3812   PetscFunctionBegin;
3813   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3814   PetscValidIntPointer(lits,2);
3815   *lits = ts->ksp_its;
3816   PetscFunctionReturn(0);
3817 }
3818 
3819 #undef __FUNCT__
3820 #define __FUNCT__ "TSGetStepRejections"
3821 /*@
3822    TSGetStepRejections - Gets the total number of rejected steps.
3823 
3824    Not Collective
3825 
3826    Input Parameter:
3827 .  ts - TS context
3828 
3829    Output Parameter:
3830 .  rejects - number of steps rejected
3831 
3832    Notes:
3833    This counter is reset to zero for each successive call to TSSolve().
3834 
3835    Level: intermediate
3836 
3837 .keywords: TS, get, number
3838 
3839 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetSNESFailures(), TSSetMaxSNESFailures(), TSSetErrorIfStepFails()
3840 @*/
3841 PetscErrorCode TSGetStepRejections(TS ts,PetscInt *rejects)
3842 {
3843   PetscFunctionBegin;
3844   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3845   PetscValidIntPointer(rejects,2);
3846   *rejects = ts->reject;
3847   PetscFunctionReturn(0);
3848 }
3849 
3850 #undef __FUNCT__
3851 #define __FUNCT__ "TSGetSNESFailures"
3852 /*@
3853    TSGetSNESFailures - Gets the total number of failed SNES solves
3854 
3855    Not Collective
3856 
3857    Input Parameter:
3858 .  ts - TS context
3859 
3860    Output Parameter:
3861 .  fails - number of failed nonlinear solves
3862 
3863    Notes:
3864    This counter is reset to zero for each successive call to TSSolve().
3865 
3866    Level: intermediate
3867 
3868 .keywords: TS, get, number
3869 
3870 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSSetMaxSNESFailures()
3871 @*/
3872 PetscErrorCode TSGetSNESFailures(TS ts,PetscInt *fails)
3873 {
3874   PetscFunctionBegin;
3875   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3876   PetscValidIntPointer(fails,2);
3877   *fails = ts->num_snes_failures;
3878   PetscFunctionReturn(0);
3879 }
3880 
3881 #undef __FUNCT__
3882 #define __FUNCT__ "TSSetMaxStepRejections"
3883 /*@
3884    TSSetMaxStepRejections - Sets the maximum number of step rejections before a step fails
3885 
3886    Not Collective
3887 
3888    Input Parameter:
3889 +  ts - TS context
3890 -  rejects - maximum number of rejected steps, pass -1 for unlimited
3891 
3892    Notes:
3893    The counter is reset to zero for each step
3894 
3895    Options Database Key:
3896  .  -ts_max_reject - Maximum number of step rejections before a step fails
3897 
3898    Level: intermediate
3899 
3900 .keywords: TS, set, maximum, number
3901 
3902 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxSNESFailures(), TSGetStepRejections(), TSGetSNESFailures(), TSSetErrorIfStepFails(), TSGetConvergedReason()
3903 @*/
3904 PetscErrorCode TSSetMaxStepRejections(TS ts,PetscInt rejects)
3905 {
3906   PetscFunctionBegin;
3907   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3908   ts->max_reject = rejects;
3909   PetscFunctionReturn(0);
3910 }
3911 
3912 #undef __FUNCT__
3913 #define __FUNCT__ "TSSetMaxSNESFailures"
3914 /*@
3915    TSSetMaxSNESFailures - Sets the maximum number of failed SNES solves
3916 
3917    Not Collective
3918 
3919    Input Parameter:
3920 +  ts - TS context
3921 -  fails - maximum number of failed nonlinear solves, pass -1 for unlimited
3922 
3923    Notes:
3924    The counter is reset to zero for each successive call to TSSolve().
3925 
3926    Options Database Key:
3927  .  -ts_max_snes_failures - Maximum number of nonlinear solve failures
3928 
3929    Level: intermediate
3930 
3931 .keywords: TS, set, maximum, number
3932 
3933 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSGetSNESFailures(), SNESGetConvergedReason(), TSGetConvergedReason()
3934 @*/
3935 PetscErrorCode TSSetMaxSNESFailures(TS ts,PetscInt fails)
3936 {
3937   PetscFunctionBegin;
3938   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3939   ts->max_snes_failures = fails;
3940   PetscFunctionReturn(0);
3941 }
3942 
3943 #undef __FUNCT__
3944 #define __FUNCT__ "TSSetErrorIfStepFails()"
3945 /*@
3946    TSSetErrorIfStepFails - Error if no step succeeds
3947 
3948    Not Collective
3949 
3950    Input Parameter:
3951 +  ts - TS context
3952 -  err - PETSC_TRUE to error if no step succeeds, PETSC_FALSE to return without failure
3953 
3954    Options Database Key:
3955  .  -ts_error_if_step_fails - Error if no step succeeds
3956 
3957    Level: intermediate
3958 
3959 .keywords: TS, set, error
3960 
3961 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSGetSNESFailures(), TSSetErrorIfStepFails(), TSGetConvergedReason()
3962 @*/
3963 PetscErrorCode TSSetErrorIfStepFails(TS ts,PetscBool err)
3964 {
3965   PetscFunctionBegin;
3966   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3967   ts->errorifstepfailed = err;
3968   PetscFunctionReturn(0);
3969 }
3970 
3971 #undef __FUNCT__
3972 #define __FUNCT__ "TSMonitorSolutionBinary"
3973 /*@C
3974    TSMonitorSolutionBinary - Monitors progress of the TS solvers by VecView() for the solution at each timestep. Normally the viewer is a binary file
3975 
3976    Collective on TS
3977 
3978    Input Parameters:
3979 +  ts - the TS context
3980 .  step - current time-step
3981 .  ptime - current time
3982 .  u - current state
3983 -  viewer - binary viewer
3984 
3985    Level: intermediate
3986 
3987 .keywords: TS,  vector, monitor, view
3988 
3989 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3990 @*/
3991 PetscErrorCode  TSMonitorSolutionBinary(TS ts,PetscInt step,PetscReal ptime,Vec u,void *viewer)
3992 {
3993   PetscErrorCode ierr;
3994   PetscViewer    v = (PetscViewer)viewer;
3995 
3996   PetscFunctionBegin;
3997   ierr = VecView(u,v);CHKERRQ(ierr);
3998   PetscFunctionReturn(0);
3999 }
4000 
4001 #undef __FUNCT__
4002 #define __FUNCT__ "TSMonitorSolutionVTK"
4003 /*@C
4004    TSMonitorSolutionVTK - Monitors progress of the TS solvers by VecView() for the solution at each timestep.
4005 
4006    Collective on TS
4007 
4008    Input Parameters:
4009 +  ts - the TS context
4010 .  step - current time-step
4011 .  ptime - current time
4012 .  u - current state
4013 -  filenametemplate - string containing a format specifier for the integer time step (e.g. %03D)
4014 
4015    Level: intermediate
4016 
4017    Notes:
4018    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.
4019    These are named according to the file name template.
4020 
4021    This function is normally passed as an argument to TSMonitorSet() along with TSMonitorSolutionVTKDestroy().
4022 
4023 .keywords: TS,  vector, monitor, view
4024 
4025 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
4026 @*/
4027 PetscErrorCode TSMonitorSolutionVTK(TS ts,PetscInt step,PetscReal ptime,Vec u,void *filenametemplate)
4028 {
4029   PetscErrorCode ierr;
4030   char           filename[PETSC_MAX_PATH_LEN];
4031   PetscViewer    viewer;
4032 
4033   PetscFunctionBegin;
4034   ierr = PetscSNPrintf(filename,sizeof(filename),(const char*)filenametemplate,step);CHKERRQ(ierr);
4035   ierr = PetscViewerVTKOpen(PetscObjectComm((PetscObject)ts),filename,FILE_MODE_WRITE,&viewer);CHKERRQ(ierr);
4036   ierr = VecView(u,viewer);CHKERRQ(ierr);
4037   ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
4038   PetscFunctionReturn(0);
4039 }
4040 
4041 #undef __FUNCT__
4042 #define __FUNCT__ "TSMonitorSolutionVTKDestroy"
4043 /*@C
4044    TSMonitorSolutionVTKDestroy - Destroy context for monitoring
4045 
4046    Collective on TS
4047 
4048    Input Parameters:
4049 .  filenametemplate - string containing a format specifier for the integer time step (e.g. %03D)
4050 
4051    Level: intermediate
4052 
4053    Note:
4054    This function is normally passed to TSMonitorSet() along with TSMonitorSolutionVTK().
4055 
4056 .keywords: TS,  vector, monitor, view
4057 
4058 .seealso: TSMonitorSet(), TSMonitorSolutionVTK()
4059 @*/
4060 PetscErrorCode TSMonitorSolutionVTKDestroy(void *filenametemplate)
4061 {
4062   PetscErrorCode ierr;
4063 
4064   PetscFunctionBegin;
4065   ierr = PetscFree(*(char**)filenametemplate);CHKERRQ(ierr);
4066   PetscFunctionReturn(0);
4067 }
4068 
4069 #undef __FUNCT__
4070 #define __FUNCT__ "TSGetAdapt"
4071 /*@
4072    TSGetAdapt - Get the adaptive controller context for the current method
4073 
4074    Collective on TS if controller has not been created yet
4075 
4076    Input Arguments:
4077 .  ts - time stepping context
4078 
4079    Output Arguments:
4080 .  adapt - adaptive controller
4081 
4082    Level: intermediate
4083 
4084 .seealso: TSAdapt, TSAdaptSetType(), TSAdaptChoose()
4085 @*/
4086 PetscErrorCode TSGetAdapt(TS ts,TSAdapt *adapt)
4087 {
4088   PetscErrorCode ierr;
4089 
4090   PetscFunctionBegin;
4091   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4092   PetscValidPointer(adapt,2);
4093   if (!ts->adapt) {
4094     ierr = TSAdaptCreate(PetscObjectComm((PetscObject)ts),&ts->adapt);CHKERRQ(ierr);
4095     ierr = PetscLogObjectParent(ts,ts->adapt);CHKERRQ(ierr);
4096     ierr = PetscObjectIncrementTabLevel((PetscObject)ts->adapt,(PetscObject)ts,1);CHKERRQ(ierr);
4097   }
4098   *adapt = ts->adapt;
4099   PetscFunctionReturn(0);
4100 }
4101 
4102 #undef __FUNCT__
4103 #define __FUNCT__ "TSSetTolerances"
4104 /*@
4105    TSSetTolerances - Set tolerances for local truncation error when using adaptive controller
4106 
4107    Logically Collective
4108 
4109    Input Arguments:
4110 +  ts - time integration context
4111 .  atol - scalar absolute tolerances, PETSC_DECIDE to leave current value
4112 .  vatol - vector of absolute tolerances or NULL, used in preference to atol if present
4113 .  rtol - scalar relative tolerances, PETSC_DECIDE to leave current value
4114 -  vrtol - vector of relative tolerances or NULL, used in preference to atol if present
4115 
4116    Level: beginner
4117 
4118 .seealso: TS, TSAdapt, TSVecNormWRMS(), TSGetTolerances()
4119 @*/
4120 PetscErrorCode TSSetTolerances(TS ts,PetscReal atol,Vec vatol,PetscReal rtol,Vec vrtol)
4121 {
4122   PetscErrorCode ierr;
4123 
4124   PetscFunctionBegin;
4125   if (atol != PETSC_DECIDE && atol != PETSC_DEFAULT) ts->atol = atol;
4126   if (vatol) {
4127     ierr = PetscObjectReference((PetscObject)vatol);CHKERRQ(ierr);
4128     ierr = VecDestroy(&ts->vatol);CHKERRQ(ierr);
4129 
4130     ts->vatol = vatol;
4131   }
4132   if (rtol != PETSC_DECIDE && rtol != PETSC_DEFAULT) ts->rtol = rtol;
4133   if (vrtol) {
4134     ierr = PetscObjectReference((PetscObject)vrtol);CHKERRQ(ierr);
4135     ierr = VecDestroy(&ts->vrtol);CHKERRQ(ierr);
4136 
4137     ts->vrtol = vrtol;
4138   }
4139   PetscFunctionReturn(0);
4140 }
4141 
4142 #undef __FUNCT__
4143 #define __FUNCT__ "TSGetTolerances"
4144 /*@
4145    TSGetTolerances - Get tolerances for local truncation error when using adaptive controller
4146 
4147    Logically Collective
4148 
4149    Input Arguments:
4150 .  ts - time integration context
4151 
4152    Output Arguments:
4153 +  atol - scalar absolute tolerances, NULL to ignore
4154 .  vatol - vector of absolute tolerances, NULL to ignore
4155 .  rtol - scalar relative tolerances, NULL to ignore
4156 -  vrtol - vector of relative tolerances, NULL to ignore
4157 
4158    Level: beginner
4159 
4160 .seealso: TS, TSAdapt, TSVecNormWRMS(), TSSetTolerances()
4161 @*/
4162 PetscErrorCode TSGetTolerances(TS ts,PetscReal *atol,Vec *vatol,PetscReal *rtol,Vec *vrtol)
4163 {
4164   PetscFunctionBegin;
4165   if (atol)  *atol  = ts->atol;
4166   if (vatol) *vatol = ts->vatol;
4167   if (rtol)  *rtol  = ts->rtol;
4168   if (vrtol) *vrtol = ts->vrtol;
4169   PetscFunctionReturn(0);
4170 }
4171 
4172 #undef __FUNCT__
4173 #define __FUNCT__ "TSErrorNormWRMS"
4174 /*@
4175    TSErrorNormWRMS - compute a weighted norm of the difference between a vector and the current state
4176 
4177    Collective on TS
4178 
4179    Input Arguments:
4180 +  ts - time stepping context
4181 -  Y - state vector to be compared to ts->vec_sol
4182 
4183    Output Arguments:
4184 .  norm - weighted norm, a value of 1.0 is considered small
4185 
4186    Level: developer
4187 
4188 .seealso: TSSetTolerances()
4189 @*/
4190 PetscErrorCode TSErrorNormWRMS(TS ts,Vec Y,PetscReal *norm)
4191 {
4192   PetscErrorCode    ierr;
4193   PetscInt          i,n,N;
4194   const PetscScalar *u,*y;
4195   Vec               U;
4196   PetscReal         sum,gsum;
4197 
4198   PetscFunctionBegin;
4199   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4200   PetscValidHeaderSpecific(Y,VEC_CLASSID,2);
4201   PetscValidPointer(norm,3);
4202   U = ts->vec_sol;
4203   PetscCheckSameTypeAndComm(U,1,Y,2);
4204   if (U == Y) SETERRQ(PetscObjectComm((PetscObject)U),PETSC_ERR_ARG_IDN,"Y cannot be the TS solution vector");
4205 
4206   ierr = VecGetSize(U,&N);CHKERRQ(ierr);
4207   ierr = VecGetLocalSize(U,&n);CHKERRQ(ierr);
4208   ierr = VecGetArrayRead(U,&u);CHKERRQ(ierr);
4209   ierr = VecGetArrayRead(Y,&y);CHKERRQ(ierr);
4210   sum  = 0.;
4211   if (ts->vatol && ts->vrtol) {
4212     const PetscScalar *atol,*rtol;
4213     ierr = VecGetArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4214     ierr = VecGetArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4215     for (i=0; i<n; i++) {
4216       PetscReal tol = PetscRealPart(atol[i]) + PetscRealPart(rtol[i]) * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4217       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4218     }
4219     ierr = VecRestoreArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4220     ierr = VecRestoreArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4221   } else if (ts->vatol) {       /* vector atol, scalar rtol */
4222     const PetscScalar *atol;
4223     ierr = VecGetArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4224     for (i=0; i<n; i++) {
4225       PetscReal tol = PetscRealPart(atol[i]) + ts->rtol * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4226       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4227     }
4228     ierr = VecRestoreArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4229   } else if (ts->vrtol) {       /* scalar atol, vector rtol */
4230     const PetscScalar *rtol;
4231     ierr = VecGetArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4232     for (i=0; i<n; i++) {
4233       PetscReal tol = ts->atol + PetscRealPart(rtol[i]) * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4234       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4235     }
4236     ierr = VecRestoreArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4237   } else {                      /* scalar atol, scalar rtol */
4238     for (i=0; i<n; i++) {
4239       PetscReal tol = ts->atol + ts->rtol * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4240       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4241     }
4242   }
4243   ierr = VecRestoreArrayRead(U,&u);CHKERRQ(ierr);
4244   ierr = VecRestoreArrayRead(Y,&y);CHKERRQ(ierr);
4245 
4246   ierr  = MPI_Allreduce(&sum,&gsum,1,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)ts));CHKERRQ(ierr);
4247   *norm = PetscSqrtReal(gsum / N);
4248   if (PetscIsInfOrNanScalar(*norm)) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_FP,"Infinite or not-a-number generated in norm");
4249   PetscFunctionReturn(0);
4250 }
4251 
4252 #undef __FUNCT__
4253 #define __FUNCT__ "TSSetCFLTimeLocal"
4254 /*@
4255    TSSetCFLTimeLocal - Set the local CFL constraint relative to forward Euler
4256 
4257    Logically Collective on TS
4258 
4259    Input Arguments:
4260 +  ts - time stepping context
4261 -  cfltime - maximum stable time step if using forward Euler (value can be different on each process)
4262 
4263    Note:
4264    After calling this function, the global CFL time can be obtained by calling TSGetCFLTime()
4265 
4266    Level: intermediate
4267 
4268 .seealso: TSGetCFLTime(), TSADAPTCFL
4269 @*/
4270 PetscErrorCode TSSetCFLTimeLocal(TS ts,PetscReal cfltime)
4271 {
4272   PetscFunctionBegin;
4273   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4274   ts->cfltime_local = cfltime;
4275   ts->cfltime       = -1.;
4276   PetscFunctionReturn(0);
4277 }
4278 
4279 #undef __FUNCT__
4280 #define __FUNCT__ "TSGetCFLTime"
4281 /*@
4282    TSGetCFLTime - Get the maximum stable time step according to CFL criteria applied to forward Euler
4283 
4284    Collective on TS
4285 
4286    Input Arguments:
4287 .  ts - time stepping context
4288 
4289    Output Arguments:
4290 .  cfltime - maximum stable time step for forward Euler
4291 
4292    Level: advanced
4293 
4294 .seealso: TSSetCFLTimeLocal()
4295 @*/
4296 PetscErrorCode TSGetCFLTime(TS ts,PetscReal *cfltime)
4297 {
4298   PetscErrorCode ierr;
4299 
4300   PetscFunctionBegin;
4301   if (ts->cfltime < 0) {
4302     ierr = MPI_Allreduce(&ts->cfltime_local,&ts->cfltime,1,MPIU_REAL,MPIU_MIN,PetscObjectComm((PetscObject)ts));CHKERRQ(ierr);
4303   }
4304   *cfltime = ts->cfltime;
4305   PetscFunctionReturn(0);
4306 }
4307 
4308 #undef __FUNCT__
4309 #define __FUNCT__ "TSVISetVariableBounds"
4310 /*@
4311    TSVISetVariableBounds - Sets the lower and upper bounds for the solution vector. xl <= x <= xu
4312 
4313    Input Parameters:
4314 .  ts   - the TS context.
4315 .  xl   - lower bound.
4316 .  xu   - upper bound.
4317 
4318    Notes:
4319    If this routine is not called then the lower and upper bounds are set to
4320    SNES_VI_NINF and SNES_VI_INF respectively during SNESSetUp().
4321 
4322    Level: advanced
4323 
4324 @*/
4325 PetscErrorCode TSVISetVariableBounds(TS ts, Vec xl, Vec xu)
4326 {
4327   PetscErrorCode ierr;
4328   SNES           snes;
4329 
4330   PetscFunctionBegin;
4331   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
4332   ierr = SNESVISetVariableBounds(snes,xl,xu);CHKERRQ(ierr);
4333   PetscFunctionReturn(0);
4334 }
4335 
4336 #if defined(PETSC_HAVE_MATLAB_ENGINE)
4337 #include <mex.h>
4338 
4339 typedef struct {char *funcname; mxArray *ctx;} TSMatlabContext;
4340 
4341 #undef __FUNCT__
4342 #define __FUNCT__ "TSComputeFunction_Matlab"
4343 /*
4344    TSComputeFunction_Matlab - Calls the function that has been set with
4345                          TSSetFunctionMatlab().
4346 
4347    Collective on TS
4348 
4349    Input Parameters:
4350 +  snes - the TS context
4351 -  u - input vector
4352 
4353    Output Parameter:
4354 .  y - function vector, as set by TSSetFunction()
4355 
4356    Notes:
4357    TSComputeFunction() is typically used within nonlinear solvers
4358    implementations, so most users would not generally call this routine
4359    themselves.
4360 
4361    Level: developer
4362 
4363 .keywords: TS, nonlinear, compute, function
4364 
4365 .seealso: TSSetFunction(), TSGetFunction()
4366 */
4367 PetscErrorCode  TSComputeFunction_Matlab(TS snes,PetscReal time,Vec u,Vec udot,Vec y, void *ctx)
4368 {
4369   PetscErrorCode  ierr;
4370   TSMatlabContext *sctx = (TSMatlabContext*)ctx;
4371   int             nlhs  = 1,nrhs = 7;
4372   mxArray         *plhs[1],*prhs[7];
4373   long long int   lx = 0,lxdot = 0,ly = 0,ls = 0;
4374 
4375   PetscFunctionBegin;
4376   PetscValidHeaderSpecific(snes,TS_CLASSID,1);
4377   PetscValidHeaderSpecific(u,VEC_CLASSID,3);
4378   PetscValidHeaderSpecific(udot,VEC_CLASSID,4);
4379   PetscValidHeaderSpecific(y,VEC_CLASSID,5);
4380   PetscCheckSameComm(snes,1,u,3);
4381   PetscCheckSameComm(snes,1,y,5);
4382 
4383   ierr = PetscMemcpy(&ls,&snes,sizeof(snes));CHKERRQ(ierr);
4384   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4385   ierr = PetscMemcpy(&lxdot,&udot,sizeof(udot));CHKERRQ(ierr);
4386   ierr = PetscMemcpy(&ly,&y,sizeof(u));CHKERRQ(ierr);
4387 
4388   prhs[0] =  mxCreateDoubleScalar((double)ls);
4389   prhs[1] =  mxCreateDoubleScalar(time);
4390   prhs[2] =  mxCreateDoubleScalar((double)lx);
4391   prhs[3] =  mxCreateDoubleScalar((double)lxdot);
4392   prhs[4] =  mxCreateDoubleScalar((double)ly);
4393   prhs[5] =  mxCreateString(sctx->funcname);
4394   prhs[6] =  sctx->ctx;
4395   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSComputeFunctionInternal");CHKERRQ(ierr);
4396   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4397   mxDestroyArray(prhs[0]);
4398   mxDestroyArray(prhs[1]);
4399   mxDestroyArray(prhs[2]);
4400   mxDestroyArray(prhs[3]);
4401   mxDestroyArray(prhs[4]);
4402   mxDestroyArray(prhs[5]);
4403   mxDestroyArray(plhs[0]);
4404   PetscFunctionReturn(0);
4405 }
4406 
4407 
4408 #undef __FUNCT__
4409 #define __FUNCT__ "TSSetFunctionMatlab"
4410 /*
4411    TSSetFunctionMatlab - Sets the function evaluation routine and function
4412    vector for use by the TS routines in solving ODEs
4413    equations from MATLAB. Here the function is a string containing the name of a MATLAB function
4414 
4415    Logically Collective on TS
4416 
4417    Input Parameters:
4418 +  ts - the TS context
4419 -  func - function evaluation routine
4420 
4421    Calling sequence of func:
4422 $    func (TS ts,PetscReal time,Vec u,Vec udot,Vec f,void *ctx);
4423 
4424    Level: beginner
4425 
4426 .keywords: TS, nonlinear, set, function
4427 
4428 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4429 */
4430 PetscErrorCode  TSSetFunctionMatlab(TS ts,const char *func,mxArray *ctx)
4431 {
4432   PetscErrorCode  ierr;
4433   TSMatlabContext *sctx;
4434 
4435   PetscFunctionBegin;
4436   /* currently sctx is memory bleed */
4437   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4438   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4439   /*
4440      This should work, but it doesn't
4441   sctx->ctx = ctx;
4442   mexMakeArrayPersistent(sctx->ctx);
4443   */
4444   sctx->ctx = mxDuplicateArray(ctx);
4445 
4446   ierr = TSSetIFunction(ts,NULL,TSComputeFunction_Matlab,sctx);CHKERRQ(ierr);
4447   PetscFunctionReturn(0);
4448 }
4449 
4450 #undef __FUNCT__
4451 #define __FUNCT__ "TSComputeJacobian_Matlab"
4452 /*
4453    TSComputeJacobian_Matlab - Calls the function that has been set with
4454                          TSSetJacobianMatlab().
4455 
4456    Collective on TS
4457 
4458    Input Parameters:
4459 +  ts - the TS context
4460 .  u - input vector
4461 .  A, B - the matrices
4462 -  ctx - user context
4463 
4464    Output Parameter:
4465 .  flag - structure of the matrix
4466 
4467    Level: developer
4468 
4469 .keywords: TS, nonlinear, compute, function
4470 
4471 .seealso: TSSetFunction(), TSGetFunction()
4472 @*/
4473 PetscErrorCode  TSComputeJacobian_Matlab(TS ts,PetscReal time,Vec u,Vec udot,PetscReal shift,Mat *A,Mat *B,MatStructure *flag, void *ctx)
4474 {
4475   PetscErrorCode  ierr;
4476   TSMatlabContext *sctx = (TSMatlabContext*)ctx;
4477   int             nlhs  = 2,nrhs = 9;
4478   mxArray         *plhs[2],*prhs[9];
4479   long long int   lx = 0,lxdot = 0,lA = 0,ls = 0, lB = 0;
4480 
4481   PetscFunctionBegin;
4482   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4483   PetscValidHeaderSpecific(u,VEC_CLASSID,3);
4484 
4485   /* call Matlab function in ctx with arguments u and y */
4486 
4487   ierr = PetscMemcpy(&ls,&ts,sizeof(ts));CHKERRQ(ierr);
4488   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4489   ierr = PetscMemcpy(&lxdot,&udot,sizeof(u));CHKERRQ(ierr);
4490   ierr = PetscMemcpy(&lA,A,sizeof(u));CHKERRQ(ierr);
4491   ierr = PetscMemcpy(&lB,B,sizeof(u));CHKERRQ(ierr);
4492 
4493   prhs[0] =  mxCreateDoubleScalar((double)ls);
4494   prhs[1] =  mxCreateDoubleScalar((double)time);
4495   prhs[2] =  mxCreateDoubleScalar((double)lx);
4496   prhs[3] =  mxCreateDoubleScalar((double)lxdot);
4497   prhs[4] =  mxCreateDoubleScalar((double)shift);
4498   prhs[5] =  mxCreateDoubleScalar((double)lA);
4499   prhs[6] =  mxCreateDoubleScalar((double)lB);
4500   prhs[7] =  mxCreateString(sctx->funcname);
4501   prhs[8] =  sctx->ctx;
4502   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSComputeJacobianInternal");CHKERRQ(ierr);
4503   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4504   *flag   =  (MatStructure) mxGetScalar(plhs[1]);CHKERRQ(ierr);
4505   mxDestroyArray(prhs[0]);
4506   mxDestroyArray(prhs[1]);
4507   mxDestroyArray(prhs[2]);
4508   mxDestroyArray(prhs[3]);
4509   mxDestroyArray(prhs[4]);
4510   mxDestroyArray(prhs[5]);
4511   mxDestroyArray(prhs[6]);
4512   mxDestroyArray(prhs[7]);
4513   mxDestroyArray(plhs[0]);
4514   mxDestroyArray(plhs[1]);
4515   PetscFunctionReturn(0);
4516 }
4517 
4518 
4519 #undef __FUNCT__
4520 #define __FUNCT__ "TSSetJacobianMatlab"
4521 /*
4522    TSSetJacobianMatlab - Sets the Jacobian function evaluation routine and two empty Jacobian matrices
4523    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
4524 
4525    Logically Collective on TS
4526 
4527    Input Parameters:
4528 +  ts - the TS context
4529 .  A,B - Jacobian matrices
4530 .  func - function evaluation routine
4531 -  ctx - user context
4532 
4533    Calling sequence of func:
4534 $    flag = func (TS ts,PetscReal time,Vec u,Vec udot,Mat A,Mat B,void *ctx);
4535 
4536 
4537    Level: developer
4538 
4539 .keywords: TS, nonlinear, set, function
4540 
4541 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4542 */
4543 PetscErrorCode  TSSetJacobianMatlab(TS ts,Mat A,Mat B,const char *func,mxArray *ctx)
4544 {
4545   PetscErrorCode  ierr;
4546   TSMatlabContext *sctx;
4547 
4548   PetscFunctionBegin;
4549   /* currently sctx is memory bleed */
4550   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4551   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4552   /*
4553      This should work, but it doesn't
4554   sctx->ctx = ctx;
4555   mexMakeArrayPersistent(sctx->ctx);
4556   */
4557   sctx->ctx = mxDuplicateArray(ctx);
4558 
4559   ierr = TSSetIJacobian(ts,A,B,TSComputeJacobian_Matlab,sctx);CHKERRQ(ierr);
4560   PetscFunctionReturn(0);
4561 }
4562 
4563 #undef __FUNCT__
4564 #define __FUNCT__ "TSMonitor_Matlab"
4565 /*
4566    TSMonitor_Matlab - Calls the function that has been set with TSMonitorSetMatlab().
4567 
4568    Collective on TS
4569 
4570 .seealso: TSSetFunction(), TSGetFunction()
4571 @*/
4572 PetscErrorCode  TSMonitor_Matlab(TS ts,PetscInt it, PetscReal time,Vec u, void *ctx)
4573 {
4574   PetscErrorCode  ierr;
4575   TSMatlabContext *sctx = (TSMatlabContext*)ctx;
4576   int             nlhs  = 1,nrhs = 6;
4577   mxArray         *plhs[1],*prhs[6];
4578   long long int   lx = 0,ls = 0;
4579 
4580   PetscFunctionBegin;
4581   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4582   PetscValidHeaderSpecific(u,VEC_CLASSID,4);
4583 
4584   ierr = PetscMemcpy(&ls,&ts,sizeof(ts));CHKERRQ(ierr);
4585   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4586 
4587   prhs[0] =  mxCreateDoubleScalar((double)ls);
4588   prhs[1] =  mxCreateDoubleScalar((double)it);
4589   prhs[2] =  mxCreateDoubleScalar((double)time);
4590   prhs[3] =  mxCreateDoubleScalar((double)lx);
4591   prhs[4] =  mxCreateString(sctx->funcname);
4592   prhs[5] =  sctx->ctx;
4593   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSMonitorInternal");CHKERRQ(ierr);
4594   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4595   mxDestroyArray(prhs[0]);
4596   mxDestroyArray(prhs[1]);
4597   mxDestroyArray(prhs[2]);
4598   mxDestroyArray(prhs[3]);
4599   mxDestroyArray(prhs[4]);
4600   mxDestroyArray(plhs[0]);
4601   PetscFunctionReturn(0);
4602 }
4603 
4604 
4605 #undef __FUNCT__
4606 #define __FUNCT__ "TSMonitorSetMatlab"
4607 /*
4608    TSMonitorSetMatlab - Sets the monitor function from Matlab
4609 
4610    Level: developer
4611 
4612 .keywords: TS, nonlinear, set, function
4613 
4614 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4615 */
4616 PetscErrorCode  TSMonitorSetMatlab(TS ts,const char *func,mxArray *ctx)
4617 {
4618   PetscErrorCode  ierr;
4619   TSMatlabContext *sctx;
4620 
4621   PetscFunctionBegin;
4622   /* currently sctx is memory bleed */
4623   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4624   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4625   /*
4626      This should work, but it doesn't
4627   sctx->ctx = ctx;
4628   mexMakeArrayPersistent(sctx->ctx);
4629   */
4630   sctx->ctx = mxDuplicateArray(ctx);
4631 
4632   ierr = TSMonitorSet(ts,TSMonitor_Matlab,sctx,NULL);CHKERRQ(ierr);
4633   PetscFunctionReturn(0);
4634 }
4635 #endif
4636 
4637 
4638 
4639 #undef __FUNCT__
4640 #define __FUNCT__ "TSMonitorLGSolution"
4641 /*@C
4642    TSMonitorLGSolution - Monitors progress of the TS solvers by plotting each component of the solution vector
4643        in a time based line graph
4644 
4645    Collective on TS
4646 
4647    Input Parameters:
4648 +  ts - the TS context
4649 .  step - current time-step
4650 .  ptime - current time
4651 -  lg - a line graph object
4652 
4653    Level: intermediate
4654 
4655     Notes: each process in a parallel run displays its component solutions in a separate window
4656 
4657 .keywords: TS,  vector, monitor, view
4658 
4659 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
4660 @*/
4661 PetscErrorCode  TSMonitorLGSolution(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
4662 {
4663   PetscErrorCode    ierr;
4664   TSMonitorLGCtx    ctx = (TSMonitorLGCtx)dummy;
4665   const PetscScalar *yy;
4666   PetscInt          dim;
4667 
4668   PetscFunctionBegin;
4669   if (!step) {
4670     PetscDrawAxis axis;
4671     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4672     ierr = PetscDrawAxisSetLabels(axis,"Solution as function of time","Time","Solution");CHKERRQ(ierr);
4673     ierr = VecGetLocalSize(u,&dim);CHKERRQ(ierr);
4674     ierr = PetscDrawLGSetDimension(ctx->lg,dim);CHKERRQ(ierr);
4675     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4676   }
4677   ierr = VecGetArrayRead(u,&yy);CHKERRQ(ierr);
4678 #if defined(PETSC_USE_COMPLEX)
4679   {
4680     PetscReal *yreal;
4681     PetscInt  i,n;
4682     ierr = VecGetLocalSize(u,&n);CHKERRQ(ierr);
4683     ierr = PetscMalloc(n*sizeof(PetscReal),&yreal);CHKERRQ(ierr);
4684     for (i=0; i<n; i++) yreal[i] = PetscRealPart(yy[i]);
4685     ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yreal);CHKERRQ(ierr);
4686     ierr = PetscFree(yreal);CHKERRQ(ierr);
4687   }
4688 #else
4689   ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yy);CHKERRQ(ierr);
4690 #endif
4691   ierr = VecRestoreArrayRead(u,&yy);CHKERRQ(ierr);
4692   if (((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason)) {
4693     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4694   }
4695   PetscFunctionReturn(0);
4696 }
4697 
4698 #undef __FUNCT__
4699 #define __FUNCT__ "TSMonitorLGError"
4700 /*@C
4701    TSMonitorLGError - Monitors progress of the TS solvers by plotting each component of the solution vector
4702        in a time based line graph
4703 
4704    Collective on TS
4705 
4706    Input Parameters:
4707 +  ts - the TS context
4708 .  step - current time-step
4709 .  ptime - current time
4710 -  lg - a line graph object
4711 
4712    Level: intermediate
4713 
4714    Notes:
4715    Only for sequential solves.
4716 
4717    The user must provide the solution using TSSetSolutionFunction() to use this monitor.
4718 
4719    Options Database Keys:
4720 .  -ts_monitor_lg_error - create a graphical monitor of error history
4721 
4722 .keywords: TS,  vector, monitor, view
4723 
4724 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSSetSolutionFunction()
4725 @*/
4726 PetscErrorCode  TSMonitorLGError(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
4727 {
4728   PetscErrorCode    ierr;
4729   TSMonitorLGCtx    ctx = (TSMonitorLGCtx)dummy;
4730   const PetscScalar *yy;
4731   Vec               y;
4732   PetscInt          dim;
4733 
4734   PetscFunctionBegin;
4735   if (!step) {
4736     PetscDrawAxis axis;
4737     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4738     ierr = PetscDrawAxisSetLabels(axis,"Error in solution as function of time","Time","Solution");CHKERRQ(ierr);
4739     ierr = VecGetLocalSize(u,&dim);CHKERRQ(ierr);
4740     ierr = PetscDrawLGSetDimension(ctx->lg,dim);CHKERRQ(ierr);
4741     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4742   }
4743   ierr = VecDuplicate(u,&y);CHKERRQ(ierr);
4744   ierr = TSComputeSolutionFunction(ts,ptime,y);CHKERRQ(ierr);
4745   ierr = VecAXPY(y,-1.0,u);CHKERRQ(ierr);
4746   ierr = VecGetArrayRead(y,&yy);CHKERRQ(ierr);
4747 #if defined(PETSC_USE_COMPLEX)
4748   {
4749     PetscReal *yreal;
4750     PetscInt  i,n;
4751     ierr = VecGetLocalSize(y,&n);CHKERRQ(ierr);
4752     ierr = PetscMalloc(n*sizeof(PetscReal),&yreal);CHKERRQ(ierr);
4753     for (i=0; i<n; i++) yreal[i] = PetscRealPart(yy[i]);
4754     ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yreal);CHKERRQ(ierr);
4755     ierr = PetscFree(yreal);CHKERRQ(ierr);
4756   }
4757 #else
4758   ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yy);CHKERRQ(ierr);
4759 #endif
4760   ierr = VecRestoreArrayRead(y,&yy);CHKERRQ(ierr);
4761   ierr = VecDestroy(&y);CHKERRQ(ierr);
4762   if (((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason)) {
4763     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4764   }
4765   PetscFunctionReturn(0);
4766 }
4767 
4768 #undef __FUNCT__
4769 #define __FUNCT__ "TSMonitorLGSNESIterations"
4770 PetscErrorCode TSMonitorLGSNESIterations(TS ts,PetscInt n,PetscReal ptime,Vec v,void *monctx)
4771 {
4772   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
4773   PetscReal      x   = ptime,y;
4774   PetscErrorCode ierr;
4775   PetscInt       its;
4776 
4777   PetscFunctionBegin;
4778   if (!n) {
4779     PetscDrawAxis axis;
4780 
4781     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4782     ierr = PetscDrawAxisSetLabels(axis,"Nonlinear iterations as function of time","Time","SNES Iterations");CHKERRQ(ierr);
4783     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4784 
4785     ctx->snes_its = 0;
4786   }
4787   ierr = TSGetSNESIterations(ts,&its);CHKERRQ(ierr);
4788   y    = its - ctx->snes_its;
4789   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
4790   if (((ctx->howoften > 0) && (!(n % ctx->howoften)) && (n > -1)) || ((ctx->howoften == -1) && (n == -1))) {
4791     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4792   }
4793   ctx->snes_its = its;
4794   PetscFunctionReturn(0);
4795 }
4796 
4797 #undef __FUNCT__
4798 #define __FUNCT__ "TSMonitorLGKSPIterations"
4799 PetscErrorCode TSMonitorLGKSPIterations(TS ts,PetscInt n,PetscReal ptime,Vec v,void *monctx)
4800 {
4801   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
4802   PetscReal      x   = ptime,y;
4803   PetscErrorCode ierr;
4804   PetscInt       its;
4805 
4806   PetscFunctionBegin;
4807   if (!n) {
4808     PetscDrawAxis axis;
4809 
4810     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4811     ierr = PetscDrawAxisSetLabels(axis,"Linear iterations as function of time","Time","KSP Iterations");CHKERRQ(ierr);
4812     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4813 
4814     ctx->ksp_its = 0;
4815   }
4816   ierr = TSGetKSPIterations(ts,&its);CHKERRQ(ierr);
4817   y    = its - ctx->ksp_its;
4818   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
4819   if (((ctx->howoften > 0) && (!(n % ctx->howoften)) && (n > -1)) || ((ctx->howoften == -1) && (n == -1))) {
4820     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4821   }
4822   ctx->ksp_its = its;
4823   PetscFunctionReturn(0);
4824 }
4825 
4826 #undef __FUNCT__
4827 #define __FUNCT__ "TSComputeLinearStability"
4828 /*@
4829    TSComputeLinearStability - computes the linear stability function at a point
4830 
4831    Collective on TS and Vec
4832 
4833    Input Parameters:
4834 +  ts - the TS context
4835 -  xr,xi - real and imaginary part of input arguments
4836 
4837    Output Parameters:
4838 .  yr,yi - real and imaginary part of function value
4839 
4840    Level: developer
4841 
4842 .keywords: TS, compute
4843 
4844 .seealso: TSSetRHSFunction(), TSComputeIFunction()
4845 @*/
4846 PetscErrorCode TSComputeLinearStability(TS ts,PetscReal xr,PetscReal xi,PetscReal *yr,PetscReal *yi)
4847 {
4848   PetscErrorCode ierr;
4849 
4850   PetscFunctionBegin;
4851   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4852   if (!ts->ops->linearstability) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"Linearized stability function not provided for this method");
4853   ierr = (*ts->ops->linearstability)(ts,xr,xi,yr,yi);CHKERRQ(ierr);
4854   PetscFunctionReturn(0);
4855 }
4856