xref: /petsc/src/ts/interface/ts.c (revision 24655328f080896bc75518026e6e8bd491ef3aa6)
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,"TS Object");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   PetscErrorCode ierr;
2497 
2498   PetscFunctionBegin;
2499   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2500   ierr = TSSetUp(ts);CHKERRQ(ierr);
2501 
2502   ts->reason = TS_CONVERGED_ITERATING;
2503   ts->ptime_prev = ts->ptime;
2504 
2505   ierr = PetscLogEventBegin(TS_Step,ts,0,0,0);CHKERRQ(ierr);
2506   ierr = (*ts->ops->step)(ts);CHKERRQ(ierr);
2507   ierr = PetscLogEventEnd(TS_Step,ts,0,0,0);CHKERRQ(ierr);
2508 
2509   ts->time_step_prev = ts->ptime - ts->ptime_prev;
2510 
2511   if (ts->reason < 0) {
2512     if (ts->errorifstepfailed) {
2513       if (ts->reason == TS_DIVERGED_NONLINEAR_SOLVE) {
2514         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]);
2515       } else SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_NOT_CONVERGED,"TSStep has failed due to %s",TSConvergedReasons[ts->reason]);
2516     }
2517   } else if (!ts->reason) {
2518     if (ts->steps >= ts->max_steps)     ts->reason = TS_CONVERGED_ITS;
2519     else if (ts->ptime >= ts->max_time) ts->reason = TS_CONVERGED_TIME;
2520   }
2521   PetscFunctionReturn(0);
2522 }
2523 
2524 #undef __FUNCT__
2525 #define __FUNCT__ "TSEvaluateStep"
2526 /*@
2527    TSEvaluateStep - Evaluate the solution at the end of a time step with a given order of accuracy.
2528 
2529    Collective on TS
2530 
2531    Input Arguments:
2532 +  ts - time stepping context
2533 .  order - desired order of accuracy
2534 -  done - whether the step was evaluated at this order (pass NULL to generate an error if not available)
2535 
2536    Output Arguments:
2537 .  U - state at the end of the current step
2538 
2539    Level: advanced
2540 
2541    Notes:
2542    This function cannot be called until all stages have been evaluated.
2543    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.
2544 
2545 .seealso: TSStep(), TSAdapt
2546 @*/
2547 PetscErrorCode TSEvaluateStep(TS ts,PetscInt order,Vec U,PetscBool *done)
2548 {
2549   PetscErrorCode ierr;
2550 
2551   PetscFunctionBegin;
2552   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2553   PetscValidType(ts,1);
2554   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
2555   if (!ts->ops->evaluatestep) SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"TSEvaluateStep not implemented for type '%s'",((PetscObject)ts)->type_name);
2556   ierr = (*ts->ops->evaluatestep)(ts,order,U,done);CHKERRQ(ierr);
2557   PetscFunctionReturn(0);
2558 }
2559 
2560 #undef __FUNCT__
2561 #define __FUNCT__ "TSSolve"
2562 /*@
2563    TSSolve - Steps the requested number of timesteps.
2564 
2565    Collective on TS
2566 
2567    Input Parameter:
2568 +  ts - the TS context obtained from TSCreate()
2569 -  u - the solution vector  (can be null if TSSetSolution() was used, otherwise must contain the initial conditions)
2570 
2571    Level: beginner
2572 
2573    Notes:
2574    The final time returned by this function may be different from the time of the internally
2575    held state accessible by TSGetSolution() and TSGetTime() because the method may have
2576    stepped over the final time.
2577 
2578 .keywords: TS, timestep, solve
2579 
2580 .seealso: TSCreate(), TSSetSolution(), TSStep()
2581 @*/
2582 PetscErrorCode TSSolve(TS ts,Vec u)
2583 {
2584   PetscBool         flg;
2585   PetscViewer       viewer;
2586   Vec               solution;
2587   PetscErrorCode    ierr;
2588   PetscViewerFormat format;
2589 
2590   PetscFunctionBegin;
2591   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2592   if (u) PetscValidHeaderSpecific(u,VEC_CLASSID,2);
2593   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 */
2594     PetscValidHeaderSpecific(u,VEC_CLASSID,2);
2595     if (!ts->vec_sol || u == ts->vec_sol) {
2596       ierr = VecDuplicate(u,&solution);CHKERRQ(ierr);
2597       ierr = TSSetSolution(ts,solution);CHKERRQ(ierr);
2598       ierr = VecDestroy(&solution);CHKERRQ(ierr); /* grant ownership */
2599     }
2600     ierr = VecCopy(u,ts->vec_sol);CHKERRQ(ierr);
2601   } else if (u) {
2602     ierr = TSSetSolution(ts,u);CHKERRQ(ierr);
2603   }
2604   ierr = TSSetUp(ts);CHKERRQ(ierr);
2605   /* reset time step and iteration counters */
2606   ts->steps             = 0;
2607   ts->ksp_its           = 0;
2608   ts->snes_its          = 0;
2609   ts->num_snes_failures = 0;
2610   ts->reject            = 0;
2611   ts->reason            = TS_CONVERGED_ITERATING;
2612 
2613   ierr = PetscOptionsGetViewer(PetscObjectComm((PetscObject)ts),((PetscObject)ts)->prefix,"-ts_view_pre",&viewer,&format,&flg);CHKERRQ(ierr);
2614   if (flg && !PetscPreLoadingOn) {
2615     ierr = PetscViewerPushFormat(viewer,format);CHKERRQ(ierr);
2616     ierr = TSView(ts,viewer);CHKERRQ(ierr);
2617     ierr = PetscViewerPopFormat(viewer);CHKERRQ(ierr);
2618     ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
2619   }
2620 
2621   if (ts->ops->solve) {         /* This private interface is transitional and should be removed when all implementations are updated. */
2622     ierr = (*ts->ops->solve)(ts);CHKERRQ(ierr);
2623     ierr = VecCopy(ts->vec_sol,u);CHKERRQ(ierr);
2624     ts->solvetime = ts->ptime;
2625   } else {
2626     /* steps the requested number of timesteps. */
2627     if (ts->steps >= ts->max_steps)     ts->reason = TS_CONVERGED_ITS;
2628     else if (ts->ptime >= ts->max_time) ts->reason = TS_CONVERGED_TIME;
2629     while (!ts->reason) {
2630       ierr = TSMonitor(ts,ts->steps,ts->ptime,ts->vec_sol);CHKERRQ(ierr);
2631       ierr = TSStep(ts);CHKERRQ(ierr);
2632       ierr = TSPostStep(ts);CHKERRQ(ierr);
2633     }
2634     if (ts->exact_final_time == TS_EXACTFINALTIME_INTERPOLATE && ts->ptime > ts->max_time) {
2635       ierr = TSInterpolate(ts,ts->max_time,u);CHKERRQ(ierr);
2636       ts->solvetime = ts->max_time;
2637       solution = u;
2638     } else {
2639       if (u) {ierr = VecCopy(ts->vec_sol,u);CHKERRQ(ierr);}
2640       ts->solvetime = ts->ptime;
2641       solution = ts->vec_sol;
2642     }
2643     ierr = TSMonitor(ts,ts->steps,ts->solvetime,solution);CHKERRQ(ierr);
2644   }
2645   ierr = PetscOptionsGetViewer(PetscObjectComm((PetscObject)ts),((PetscObject)ts)->prefix,"-ts_view",&viewer,&format,&flg);CHKERRQ(ierr);
2646   if (flg && !PetscPreLoadingOn) {
2647     ierr = PetscViewerPushFormat(viewer,format);CHKERRQ(ierr);
2648     ierr = TSView(ts,viewer);CHKERRQ(ierr);
2649     ierr = PetscViewerPopFormat(viewer);CHKERRQ(ierr);
2650     ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
2651   }
2652   PetscFunctionReturn(0);
2653 }
2654 
2655 #undef __FUNCT__
2656 #define __FUNCT__ "TSMonitor"
2657 /*@
2658    TSMonitor - Runs all user-provided monitor routines set using TSMonitorSet()
2659 
2660    Collective on TS
2661 
2662    Input Parameters:
2663 +  ts - time stepping context obtained from TSCreate()
2664 .  step - step number that has just completed
2665 .  ptime - model time of the state
2666 -  u - state at the current model time
2667 
2668    Notes:
2669    TSMonitor() is typically used within the time stepping implementations.
2670    Users might call this function when using the TSStep() interface instead of TSSolve().
2671 
2672    Level: advanced
2673 
2674 .keywords: TS, timestep
2675 @*/
2676 PetscErrorCode TSMonitor(TS ts,PetscInt step,PetscReal ptime,Vec u)
2677 {
2678   PetscErrorCode ierr;
2679   PetscInt       i,n = ts->numbermonitors;
2680 
2681   PetscFunctionBegin;
2682   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2683   PetscValidHeaderSpecific(u,VEC_CLASSID,4);
2684   for (i=0; i<n; i++) {
2685     ierr = (*ts->monitor[i])(ts,step,ptime,u,ts->monitorcontext[i]);CHKERRQ(ierr);
2686   }
2687   PetscFunctionReturn(0);
2688 }
2689 
2690 /* ------------------------------------------------------------------------*/
2691 struct _n_TSMonitorLGCtx {
2692   PetscDrawLG lg;
2693   PetscInt    howoften;  /* when > 0 uses step % howoften, when negative only final solution plotted */
2694   PetscInt    ksp_its,snes_its;
2695 };
2696 
2697 
2698 #undef __FUNCT__
2699 #define __FUNCT__ "TSMonitorLGCtxCreate"
2700 /*@C
2701    TSMonitorLGCtxCreate - Creates a line graph context for use with
2702    TS to monitor the solution process graphically in various ways
2703 
2704    Collective on TS
2705 
2706    Input Parameters:
2707 +  host - the X display to open, or null for the local machine
2708 .  label - the title to put in the title bar
2709 .  x, y - the screen coordinates of the upper left coordinate of the window
2710 .  m, n - the screen width and height in pixels
2711 -  howoften - if positive then determines the frequency of the plotting, if -1 then only at the final time
2712 
2713    Output Parameter:
2714 .  ctx - the context
2715 
2716    Options Database Key:
2717 +  -ts_monitor_lg_timestep - automatically sets line graph monitor
2718 .  -ts_monitor_lg_solution -
2719 .  -ts_monitor_lg_error -
2720 .  -ts_monitor_lg_ksp_iterations -
2721 .  -ts_monitor_lg_snes_iterations -
2722 -  -lg_indicate_data_points <true,false> - indicate the data points (at each time step) on the plot; default is true
2723 
2724    Notes:
2725    Use TSMonitorLGCtxDestroy() to destroy.
2726 
2727    Level: intermediate
2728 
2729 .keywords: TS, monitor, line graph, residual, seealso
2730 
2731 .seealso: TSMonitorLGTimeStep(), TSMonitorSet(), TSMonitorLGSolution(), TSMonitorLGError()
2732 
2733 @*/
2734 PetscErrorCode  TSMonitorLGCtxCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscInt howoften,TSMonitorLGCtx *ctx)
2735 {
2736   PetscDraw      win;
2737   PetscErrorCode ierr;
2738   PetscBool      flg = PETSC_TRUE;
2739 
2740   PetscFunctionBegin;
2741   ierr = PetscNew(struct _n_TSMonitorLGCtx,ctx);CHKERRQ(ierr);
2742   ierr = PetscDrawCreate(comm,host,label,x,y,m,n,&win);CHKERRQ(ierr);
2743   ierr = PetscDrawSetFromOptions(win);CHKERRQ(ierr);
2744   ierr = PetscDrawLGCreate(win,1,&(*ctx)->lg);CHKERRQ(ierr);
2745   ierr = PetscOptionsGetBool(NULL,"-lg_indicate_data_points",&flg,NULL);CHKERRQ(ierr);
2746   if (flg) {
2747     ierr = PetscDrawLGIndicateDataPoints((*ctx)->lg);CHKERRQ(ierr);
2748   }
2749   ierr = PetscLogObjectParent((*ctx)->lg,win);CHKERRQ(ierr);
2750   (*ctx)->howoften = howoften;
2751   PetscFunctionReturn(0);
2752 }
2753 
2754 #undef __FUNCT__
2755 #define __FUNCT__ "TSMonitorLGTimeStep"
2756 PetscErrorCode TSMonitorLGTimeStep(TS ts,PetscInt step,PetscReal ptime,Vec v,void *monctx)
2757 {
2758   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
2759   PetscReal      x   = ptime,y;
2760   PetscErrorCode ierr;
2761 
2762   PetscFunctionBegin;
2763   if (!step) {
2764     PetscDrawAxis axis;
2765     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
2766     ierr = PetscDrawAxisSetLabels(axis,"Timestep as function of time","Time","Time step");CHKERRQ(ierr);
2767     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
2768   }
2769   ierr = TSGetTimeStep(ts,&y);CHKERRQ(ierr);
2770   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
2771   if (((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason)) {
2772     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
2773   }
2774   PetscFunctionReturn(0);
2775 }
2776 
2777 #undef __FUNCT__
2778 #define __FUNCT__ "TSMonitorLGCtxDestroy"
2779 /*@C
2780    TSMonitorLGCtxDestroy - Destroys a line graph context that was created
2781    with TSMonitorLGCtxCreate().
2782 
2783    Collective on TSMonitorLGCtx
2784 
2785    Input Parameter:
2786 .  ctx - the monitor context
2787 
2788    Level: intermediate
2789 
2790 .keywords: TS, monitor, line graph, destroy
2791 
2792 .seealso: TSMonitorLGCtxCreate(),  TSMonitorSet(), TSMonitorLGTimeStep();
2793 @*/
2794 PetscErrorCode  TSMonitorLGCtxDestroy(TSMonitorLGCtx *ctx)
2795 {
2796   PetscDraw      draw;
2797   PetscErrorCode ierr;
2798 
2799   PetscFunctionBegin;
2800   ierr = PetscDrawLGGetDraw((*ctx)->lg,&draw);CHKERRQ(ierr);
2801   ierr = PetscDrawDestroy(&draw);CHKERRQ(ierr);
2802   ierr = PetscDrawLGDestroy(&(*ctx)->lg);CHKERRQ(ierr);
2803   ierr = PetscFree(*ctx);CHKERRQ(ierr);
2804   PetscFunctionReturn(0);
2805 }
2806 
2807 #undef __FUNCT__
2808 #define __FUNCT__ "TSGetTime"
2809 /*@
2810    TSGetTime - Gets the time of the most recently completed step.
2811 
2812    Not Collective
2813 
2814    Input Parameter:
2815 .  ts - the TS context obtained from TSCreate()
2816 
2817    Output Parameter:
2818 .  t  - the current time
2819 
2820    Level: beginner
2821 
2822    Note:
2823    When called during time step evaluation (e.g. during residual evaluation or via hooks set using TSSetPreStep(),
2824    TSSetPreStage(), or TSSetPostStep()), the time is the time at the start of the step being evaluated.
2825 
2826 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
2827 
2828 .keywords: TS, get, time
2829 @*/
2830 PetscErrorCode  TSGetTime(TS ts,PetscReal *t)
2831 {
2832   PetscFunctionBegin;
2833   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2834   PetscValidRealPointer(t,2);
2835   *t = ts->ptime;
2836   PetscFunctionReturn(0);
2837 }
2838 
2839 #undef __FUNCT__
2840 #define __FUNCT__ "TSSetTime"
2841 /*@
2842    TSSetTime - Allows one to reset the time.
2843 
2844    Logically Collective on TS
2845 
2846    Input Parameters:
2847 +  ts - the TS context obtained from TSCreate()
2848 -  time - the time
2849 
2850    Level: intermediate
2851 
2852 .seealso: TSGetTime(), TSSetDuration()
2853 
2854 .keywords: TS, set, time
2855 @*/
2856 PetscErrorCode  TSSetTime(TS ts, PetscReal t)
2857 {
2858   PetscFunctionBegin;
2859   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2860   PetscValidLogicalCollectiveReal(ts,t,2);
2861   ts->ptime = t;
2862   PetscFunctionReturn(0);
2863 }
2864 
2865 #undef __FUNCT__
2866 #define __FUNCT__ "TSSetOptionsPrefix"
2867 /*@C
2868    TSSetOptionsPrefix - Sets the prefix used for searching for all
2869    TS options in the database.
2870 
2871    Logically Collective on TS
2872 
2873    Input Parameter:
2874 +  ts     - The TS context
2875 -  prefix - The prefix to prepend to all option names
2876 
2877    Notes:
2878    A hyphen (-) must NOT be given at the beginning of the prefix name.
2879    The first character of all runtime options is AUTOMATICALLY the
2880    hyphen.
2881 
2882    Level: advanced
2883 
2884 .keywords: TS, set, options, prefix, database
2885 
2886 .seealso: TSSetFromOptions()
2887 
2888 @*/
2889 PetscErrorCode  TSSetOptionsPrefix(TS ts,const char prefix[])
2890 {
2891   PetscErrorCode ierr;
2892   SNES           snes;
2893 
2894   PetscFunctionBegin;
2895   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2896   ierr = PetscObjectSetOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
2897   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2898   ierr = SNESSetOptionsPrefix(snes,prefix);CHKERRQ(ierr);
2899   PetscFunctionReturn(0);
2900 }
2901 
2902 
2903 #undef __FUNCT__
2904 #define __FUNCT__ "TSAppendOptionsPrefix"
2905 /*@C
2906    TSAppendOptionsPrefix - Appends to the prefix used for searching for all
2907    TS options in the database.
2908 
2909    Logically Collective on TS
2910 
2911    Input Parameter:
2912 +  ts     - The TS context
2913 -  prefix - The prefix to prepend to all option names
2914 
2915    Notes:
2916    A hyphen (-) must NOT be given at the beginning of the prefix name.
2917    The first character of all runtime options is AUTOMATICALLY the
2918    hyphen.
2919 
2920    Level: advanced
2921 
2922 .keywords: TS, append, options, prefix, database
2923 
2924 .seealso: TSGetOptionsPrefix()
2925 
2926 @*/
2927 PetscErrorCode  TSAppendOptionsPrefix(TS ts,const char prefix[])
2928 {
2929   PetscErrorCode ierr;
2930   SNES           snes;
2931 
2932   PetscFunctionBegin;
2933   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2934   ierr = PetscObjectAppendOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
2935   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2936   ierr = SNESAppendOptionsPrefix(snes,prefix);CHKERRQ(ierr);
2937   PetscFunctionReturn(0);
2938 }
2939 
2940 #undef __FUNCT__
2941 #define __FUNCT__ "TSGetOptionsPrefix"
2942 /*@C
2943    TSGetOptionsPrefix - Sets the prefix used for searching for all
2944    TS options in the database.
2945 
2946    Not Collective
2947 
2948    Input Parameter:
2949 .  ts - The TS context
2950 
2951    Output Parameter:
2952 .  prefix - A pointer to the prefix string used
2953 
2954    Notes: On the fortran side, the user should pass in a string 'prifix' of
2955    sufficient length to hold the prefix.
2956 
2957    Level: intermediate
2958 
2959 .keywords: TS, get, options, prefix, database
2960 
2961 .seealso: TSAppendOptionsPrefix()
2962 @*/
2963 PetscErrorCode  TSGetOptionsPrefix(TS ts,const char *prefix[])
2964 {
2965   PetscErrorCode ierr;
2966 
2967   PetscFunctionBegin;
2968   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2969   PetscValidPointer(prefix,2);
2970   ierr = PetscObjectGetOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
2971   PetscFunctionReturn(0);
2972 }
2973 
2974 #undef __FUNCT__
2975 #define __FUNCT__ "TSGetRHSJacobian"
2976 /*@C
2977    TSGetRHSJacobian - Returns the Jacobian J at the present timestep.
2978 
2979    Not Collective, but parallel objects are returned if TS is parallel
2980 
2981    Input Parameter:
2982 .  ts  - The TS context obtained from TSCreate()
2983 
2984    Output Parameters:
2985 +  Amat - The (approximate) Jacobian J of G, where U_t = G(U,t)  (or NULL)
2986 .  Pmat - The matrix from which the preconditioner is constructed, usually the same as Amat  (or NULL)
2987 .  func - Function to compute the Jacobian of the RHS  (or NULL)
2988 -  ctx - User-defined context for Jacobian evaluation routine  (or NULL)
2989 
2990    Notes: You can pass in NULL for any return argument you do not need.
2991 
2992    Level: intermediate
2993 
2994 .seealso: TSGetTimeStep(), TSGetMatrices(), TSGetTime(), TSGetTimeStepNumber()
2995 
2996 .keywords: TS, timestep, get, matrix, Jacobian
2997 @*/
2998 PetscErrorCode  TSGetRHSJacobian(TS ts,Mat *Amat,Mat *Pmat,TSRHSJacobian *func,void **ctx)
2999 {
3000   PetscErrorCode ierr;
3001   SNES           snes;
3002   DM             dm;
3003 
3004   PetscFunctionBegin;
3005   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3006   ierr = SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);CHKERRQ(ierr);
3007   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
3008   ierr = DMTSGetRHSJacobian(dm,func,ctx);CHKERRQ(ierr);
3009   PetscFunctionReturn(0);
3010 }
3011 
3012 #undef __FUNCT__
3013 #define __FUNCT__ "TSGetIJacobian"
3014 /*@C
3015    TSGetIJacobian - Returns the implicit Jacobian at the present timestep.
3016 
3017    Not Collective, but parallel objects are returned if TS is parallel
3018 
3019    Input Parameter:
3020 .  ts  - The TS context obtained from TSCreate()
3021 
3022    Output Parameters:
3023 +  Amat  - The (approximate) Jacobian of F(t,U,U_t)
3024 .  Pmat - The matrix from which the preconditioner is constructed, often the same as Amat
3025 .  f   - The function to compute the matrices
3026 - ctx - User-defined context for Jacobian evaluation routine
3027 
3028    Notes: You can pass in NULL for any return argument you do not need.
3029 
3030    Level: advanced
3031 
3032 .seealso: TSGetTimeStep(), TSGetRHSJacobian(), TSGetMatrices(), TSGetTime(), TSGetTimeStepNumber()
3033 
3034 .keywords: TS, timestep, get, matrix, Jacobian
3035 @*/
3036 PetscErrorCode  TSGetIJacobian(TS ts,Mat *Amat,Mat *Pmat,TSIJacobian *f,void **ctx)
3037 {
3038   PetscErrorCode ierr;
3039   SNES           snes;
3040   DM             dm;
3041 
3042   PetscFunctionBegin;
3043   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3044   ierr = SNESSetUpMatrices(snes);CHKERRQ(ierr);
3045   ierr = SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);CHKERRQ(ierr);
3046   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
3047   ierr = DMTSGetIJacobian(dm,f,ctx);CHKERRQ(ierr);
3048   PetscFunctionReturn(0);
3049 }
3050 
3051 
3052 #undef __FUNCT__
3053 #define __FUNCT__ "TSMonitorDrawSolution"
3054 /*@C
3055    TSMonitorDrawSolution - Monitors progress of the TS solvers by calling
3056    VecView() for the solution at each timestep
3057 
3058    Collective on TS
3059 
3060    Input Parameters:
3061 +  ts - the TS context
3062 .  step - current time-step
3063 .  ptime - current time
3064 -  dummy - either a viewer or NULL
3065 
3066    Options Database:
3067 .   -ts_monitor_draw_solution_initial - show initial solution as well as current solution
3068 
3069    Notes: the initial solution and current solution are not displayed with a common axis scaling so generally the option -ts_monitor_draw_solution_initial
3070        will look bad
3071 
3072    Level: intermediate
3073 
3074 .keywords: TS,  vector, monitor, view
3075 
3076 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3077 @*/
3078 PetscErrorCode  TSMonitorDrawSolution(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
3079 {
3080   PetscErrorCode   ierr;
3081   TSMonitorDrawCtx ictx = (TSMonitorDrawCtx)dummy;
3082   PetscDraw        draw;
3083 
3084   PetscFunctionBegin;
3085   if (!step && ictx->showinitial) {
3086     if (!ictx->initialsolution) {
3087       ierr = VecDuplicate(u,&ictx->initialsolution);CHKERRQ(ierr);
3088     }
3089     ierr = VecCopy(u,ictx->initialsolution);CHKERRQ(ierr);
3090   }
3091   if (!(((ictx->howoften > 0) && (!(step % ictx->howoften))) || ((ictx->howoften == -1) && ts->reason))) PetscFunctionReturn(0);
3092 
3093   if (ictx->showinitial) {
3094     PetscReal pause;
3095     ierr = PetscViewerDrawGetPause(ictx->viewer,&pause);CHKERRQ(ierr);
3096     ierr = PetscViewerDrawSetPause(ictx->viewer,0.0);CHKERRQ(ierr);
3097     ierr = VecView(ictx->initialsolution,ictx->viewer);CHKERRQ(ierr);
3098     ierr = PetscViewerDrawSetPause(ictx->viewer,pause);CHKERRQ(ierr);
3099     ierr = PetscViewerDrawSetHold(ictx->viewer,PETSC_TRUE);CHKERRQ(ierr);
3100   }
3101   ierr = VecView(u,ictx->viewer);CHKERRQ(ierr);
3102   if (ictx->showtimestepandtime) {
3103     PetscReal xl,yl,xr,yr,tw,w,h;
3104     char      time[32];
3105     size_t    len;
3106 
3107     ierr = PetscViewerDrawGetDraw(ictx->viewer,0,&draw);CHKERRQ(ierr);
3108     ierr = PetscSNPrintf(time,32,"Timestep %d Time %f",(int)step,(double)ptime);CHKERRQ(ierr);
3109     ierr = PetscDrawGetCoordinates(draw,&xl,&yl,&xr,&yr);CHKERRQ(ierr);
3110     ierr =  PetscStrlen(time,&len);CHKERRQ(ierr);
3111     ierr = PetscDrawStringGetSize(draw,&tw,NULL);CHKERRQ(ierr);
3112     w    = xl + .5*(xr - xl) - .5*len*tw;
3113     h    = yl + .95*(yr - yl);
3114     ierr = PetscDrawString(draw,w,h,PETSC_DRAW_BLACK,time);CHKERRQ(ierr);
3115     ierr = PetscDrawFlush(draw);CHKERRQ(ierr);
3116   }
3117 
3118   if (ictx->showinitial) {
3119     ierr = PetscViewerDrawSetHold(ictx->viewer,PETSC_FALSE);CHKERRQ(ierr);
3120   }
3121   PetscFunctionReturn(0);
3122 }
3123 
3124 #undef __FUNCT__
3125 #define __FUNCT__ "TSMonitorDrawSolutionPhase"
3126 /*@C
3127    TSMonitorDrawSolutionPhase - Monitors progress of the TS solvers by plotting the solution as a phase diagram
3128 
3129    Collective on TS
3130 
3131    Input Parameters:
3132 +  ts - the TS context
3133 .  step - current time-step
3134 .  ptime - current time
3135 -  dummy - either a viewer or NULL
3136 
3137    Level: intermediate
3138 
3139 .keywords: TS,  vector, monitor, view
3140 
3141 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3142 @*/
3143 PetscErrorCode  TSMonitorDrawSolutionPhase(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
3144 {
3145   PetscErrorCode    ierr;
3146   TSMonitorDrawCtx  ictx = (TSMonitorDrawCtx)dummy;
3147   PetscDraw         draw;
3148   MPI_Comm          comm;
3149   PetscInt          n;
3150   PetscMPIInt       size;
3151   PetscReal         xl,yl,xr,yr,tw,w,h;
3152   char              time[32];
3153   size_t            len;
3154   const PetscScalar *U;
3155 
3156   PetscFunctionBegin;
3157   ierr = PetscObjectGetComm((PetscObject)ts,&comm);CHKERRQ(ierr);
3158   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
3159   if (size != 1) SETERRQ(comm,PETSC_ERR_SUP,"Only allowed for sequential runs");
3160   ierr = VecGetSize(u,&n);CHKERRQ(ierr);
3161   if (n != 2) SETERRQ(comm,PETSC_ERR_SUP,"Only for ODEs with two unknowns");
3162 
3163   ierr = PetscViewerDrawGetDraw(ictx->viewer,0,&draw);CHKERRQ(ierr);
3164 
3165   ierr = VecGetArrayRead(u,&U);CHKERRQ(ierr);
3166   ierr = PetscDrawAxisGetLimits(ictx->axis,&xl,&xr,&yl,&yr);CHKERRQ(ierr);
3167   if ((PetscRealPart(U[0]) < xl) || (PetscRealPart(U[1]) < yl) || (PetscRealPart(U[0]) > xr) || (PetscRealPart(U[1]) > yr)) {
3168       ierr = VecRestoreArrayRead(u,&U);CHKERRQ(ierr);
3169       PetscFunctionReturn(0);
3170   }
3171   if (!step) ictx->color++;
3172   ierr = PetscDrawPoint(draw,PetscRealPart(U[0]),PetscRealPart(U[1]),ictx->color);CHKERRQ(ierr);
3173   ierr = VecRestoreArrayRead(u,&U);CHKERRQ(ierr);
3174 
3175   if (ictx->showtimestepandtime) {
3176     ierr = PetscDrawGetCoordinates(draw,&xl,&yl,&xr,&yr);CHKERRQ(ierr);
3177     ierr = PetscSNPrintf(time,32,"Timestep %d Time %f",(int)step,(double)ptime);CHKERRQ(ierr);
3178     ierr = PetscStrlen(time,&len);CHKERRQ(ierr);
3179     ierr = PetscDrawStringGetSize(draw,&tw,NULL);CHKERRQ(ierr);
3180     w    = xl + .5*(xr - xl) - .5*len*tw;
3181     h    = yl + .95*(yr - yl);
3182     ierr = PetscDrawString(draw,w,h,PETSC_DRAW_BLACK,time);CHKERRQ(ierr);
3183   }
3184   ierr = PetscDrawFlush(draw);CHKERRQ(ierr);
3185   PetscFunctionReturn(0);
3186 }
3187 
3188 
3189 #undef __FUNCT__
3190 #define __FUNCT__ "TSMonitorDrawCtxDestroy"
3191 /*@C
3192    TSMonitorDrawCtxDestroy - Destroys the monitor context for TSMonitorDrawSolution()
3193 
3194    Collective on TS
3195 
3196    Input Parameters:
3197 .    ctx - the monitor context
3198 
3199    Level: intermediate
3200 
3201 .keywords: TS,  vector, monitor, view
3202 
3203 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSMonitorDrawSolution(), TSMonitorDrawError()
3204 @*/
3205 PetscErrorCode  TSMonitorDrawCtxDestroy(TSMonitorDrawCtx *ictx)
3206 {
3207   PetscErrorCode ierr;
3208 
3209   PetscFunctionBegin;
3210   ierr = PetscDrawAxisDestroy(&(*ictx)->axis);CHKERRQ(ierr);
3211   ierr = PetscViewerDestroy(&(*ictx)->viewer);CHKERRQ(ierr);
3212   ierr = VecDestroy(&(*ictx)->initialsolution);CHKERRQ(ierr);
3213   ierr = PetscFree(*ictx);CHKERRQ(ierr);
3214   PetscFunctionReturn(0);
3215 }
3216 
3217 #undef __FUNCT__
3218 #define __FUNCT__ "TSMonitorDrawCtxCreate"
3219 /*@C
3220    TSMonitorDrawCtxCreate - Creates the monitor context for TSMonitorDrawCtx
3221 
3222    Collective on TS
3223 
3224    Input Parameter:
3225 .    ts - time-step context
3226 
3227    Output Patameter:
3228 .    ctx - the monitor context
3229 
3230    Options Database:
3231 .   -ts_monitor_draw_solution_initial - show initial solution as well as current solution
3232 
3233    Level: intermediate
3234 
3235 .keywords: TS,  vector, monitor, view
3236 
3237 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSMonitorDrawCtx()
3238 @*/
3239 PetscErrorCode  TSMonitorDrawCtxCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscInt howoften,TSMonitorDrawCtx *ctx)
3240 {
3241   PetscErrorCode   ierr;
3242 
3243   PetscFunctionBegin;
3244   ierr = PetscNew(struct _n_TSMonitorDrawCtx,ctx);CHKERRQ(ierr);
3245   ierr = PetscViewerDrawOpen(comm,host,label,x,y,m,n,&(*ctx)->viewer);CHKERRQ(ierr);
3246   ierr = PetscViewerSetFromOptions((*ctx)->viewer);CHKERRQ(ierr);
3247 
3248   (*ctx)->howoften    = howoften;
3249   (*ctx)->showinitial = PETSC_FALSE;
3250   ierr = PetscOptionsGetBool(NULL,"-ts_monitor_draw_solution_initial",&(*ctx)->showinitial,NULL);CHKERRQ(ierr);
3251 
3252   (*ctx)->showtimestepandtime = PETSC_FALSE;
3253   ierr = PetscOptionsGetBool(NULL,"-ts_monitor_draw_solution_show_time",&(*ctx)->showtimestepandtime,NULL);CHKERRQ(ierr);
3254   (*ctx)->color = PETSC_DRAW_WHITE;
3255   PetscFunctionReturn(0);
3256 }
3257 
3258 #undef __FUNCT__
3259 #define __FUNCT__ "TSMonitorDrawError"
3260 /*@C
3261    TSMonitorDrawError - Monitors progress of the TS solvers by calling
3262    VecView() for the error at each timestep
3263 
3264    Collective on TS
3265 
3266    Input Parameters:
3267 +  ts - the TS context
3268 .  step - current time-step
3269 .  ptime - current time
3270 -  dummy - either a viewer or NULL
3271 
3272    Level: intermediate
3273 
3274 .keywords: TS,  vector, monitor, view
3275 
3276 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3277 @*/
3278 PetscErrorCode  TSMonitorDrawError(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
3279 {
3280   PetscErrorCode   ierr;
3281   TSMonitorDrawCtx ctx    = (TSMonitorDrawCtx)dummy;
3282   PetscViewer      viewer = ctx->viewer;
3283   Vec              work;
3284 
3285   PetscFunctionBegin;
3286   if (!(((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason))) PetscFunctionReturn(0);
3287   ierr = VecDuplicate(u,&work);CHKERRQ(ierr);
3288   ierr = TSComputeSolutionFunction(ts,ptime,work);CHKERRQ(ierr);
3289   ierr = VecAXPY(work,-1.0,u);CHKERRQ(ierr);
3290   ierr = VecView(work,viewer);CHKERRQ(ierr);
3291   ierr = VecDestroy(&work);CHKERRQ(ierr);
3292   PetscFunctionReturn(0);
3293 }
3294 
3295 #include <petsc-private/dmimpl.h>
3296 #undef __FUNCT__
3297 #define __FUNCT__ "TSSetDM"
3298 /*@
3299    TSSetDM - Sets the DM that may be used by some preconditioners
3300 
3301    Logically Collective on TS and DM
3302 
3303    Input Parameters:
3304 +  ts - the preconditioner context
3305 -  dm - the dm
3306 
3307    Level: intermediate
3308 
3309 
3310 .seealso: TSGetDM(), SNESSetDM(), SNESGetDM()
3311 @*/
3312 PetscErrorCode  TSSetDM(TS ts,DM dm)
3313 {
3314   PetscErrorCode ierr;
3315   SNES           snes;
3316   DMTS           tsdm;
3317 
3318   PetscFunctionBegin;
3319   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3320   ierr = PetscObjectReference((PetscObject)dm);CHKERRQ(ierr);
3321   if (ts->dm) {               /* Move the DMTS context over to the new DM unless the new DM already has one */
3322     if (ts->dm->dmts && !dm->dmts) {
3323       ierr = DMCopyDMTS(ts->dm,dm);CHKERRQ(ierr);
3324       ierr = DMGetDMTS(ts->dm,&tsdm);CHKERRQ(ierr);
3325       if (tsdm->originaldm == ts->dm) { /* Grant write privileges to the replacement DM */
3326         tsdm->originaldm = dm;
3327       }
3328     }
3329     ierr = DMDestroy(&ts->dm);CHKERRQ(ierr);
3330   }
3331   ts->dm = dm;
3332 
3333   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3334   ierr = SNESSetDM(snes,dm);CHKERRQ(ierr);
3335   PetscFunctionReturn(0);
3336 }
3337 
3338 #undef __FUNCT__
3339 #define __FUNCT__ "TSGetDM"
3340 /*@
3341    TSGetDM - Gets the DM that may be used by some preconditioners
3342 
3343    Not Collective
3344 
3345    Input Parameter:
3346 . ts - the preconditioner context
3347 
3348    Output Parameter:
3349 .  dm - the dm
3350 
3351    Level: intermediate
3352 
3353 
3354 .seealso: TSSetDM(), SNESSetDM(), SNESGetDM()
3355 @*/
3356 PetscErrorCode  TSGetDM(TS ts,DM *dm)
3357 {
3358   PetscErrorCode ierr;
3359 
3360   PetscFunctionBegin;
3361   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3362   if (!ts->dm) {
3363     ierr = DMShellCreate(PetscObjectComm((PetscObject)ts),&ts->dm);CHKERRQ(ierr);
3364     if (ts->snes) {ierr = SNESSetDM(ts->snes,ts->dm);CHKERRQ(ierr);}
3365   }
3366   *dm = ts->dm;
3367   PetscFunctionReturn(0);
3368 }
3369 
3370 #undef __FUNCT__
3371 #define __FUNCT__ "SNESTSFormFunction"
3372 /*@
3373    SNESTSFormFunction - Function to evaluate nonlinear residual
3374 
3375    Logically Collective on SNES
3376 
3377    Input Parameter:
3378 + snes - nonlinear solver
3379 . U - the current state at which to evaluate the residual
3380 - ctx - user context, must be a TS
3381 
3382    Output Parameter:
3383 . F - the nonlinear residual
3384 
3385    Notes:
3386    This function is not normally called by users and is automatically registered with the SNES used by TS.
3387    It is most frequently passed to MatFDColoringSetFunction().
3388 
3389    Level: advanced
3390 
3391 .seealso: SNESSetFunction(), MatFDColoringSetFunction()
3392 @*/
3393 PetscErrorCode  SNESTSFormFunction(SNES snes,Vec U,Vec F,void *ctx)
3394 {
3395   TS             ts = (TS)ctx;
3396   PetscErrorCode ierr;
3397 
3398   PetscFunctionBegin;
3399   PetscValidHeaderSpecific(snes,SNES_CLASSID,1);
3400   PetscValidHeaderSpecific(U,VEC_CLASSID,2);
3401   PetscValidHeaderSpecific(F,VEC_CLASSID,3);
3402   PetscValidHeaderSpecific(ts,TS_CLASSID,4);
3403   ierr = (ts->ops->snesfunction)(snes,U,F,ts);CHKERRQ(ierr);
3404   PetscFunctionReturn(0);
3405 }
3406 
3407 #undef __FUNCT__
3408 #define __FUNCT__ "SNESTSFormJacobian"
3409 /*@
3410    SNESTSFormJacobian - Function to evaluate the Jacobian
3411 
3412    Collective on SNES
3413 
3414    Input Parameter:
3415 + snes - nonlinear solver
3416 . U - the current state at which to evaluate the residual
3417 - ctx - user context, must be a TS
3418 
3419    Output Parameter:
3420 + A - the Jacobian
3421 . B - the preconditioning matrix (may be the same as A)
3422 - flag - indicates any structure change in the matrix
3423 
3424    Notes:
3425    This function is not normally called by users and is automatically registered with the SNES used by TS.
3426 
3427    Level: developer
3428 
3429 .seealso: SNESSetJacobian()
3430 @*/
3431 PetscErrorCode  SNESTSFormJacobian(SNES snes,Vec U,Mat *A,Mat *B,MatStructure *flag,void *ctx)
3432 {
3433   TS             ts = (TS)ctx;
3434   PetscErrorCode ierr;
3435 
3436   PetscFunctionBegin;
3437   PetscValidHeaderSpecific(snes,SNES_CLASSID,1);
3438   PetscValidHeaderSpecific(U,VEC_CLASSID,2);
3439   PetscValidPointer(A,3);
3440   PetscValidHeaderSpecific(*A,MAT_CLASSID,3);
3441   PetscValidPointer(B,4);
3442   PetscValidHeaderSpecific(*B,MAT_CLASSID,4);
3443   PetscValidPointer(flag,5);
3444   PetscValidHeaderSpecific(ts,TS_CLASSID,6);
3445   ierr = (ts->ops->snesjacobian)(snes,U,A,B,flag,ts);CHKERRQ(ierr);
3446   PetscFunctionReturn(0);
3447 }
3448 
3449 #undef __FUNCT__
3450 #define __FUNCT__ "TSComputeRHSFunctionLinear"
3451 /*@C
3452    TSComputeRHSFunctionLinear - Evaluate the right hand side via the user-provided Jacobian, for linear problems only
3453 
3454    Collective on TS
3455 
3456    Input Arguments:
3457 +  ts - time stepping context
3458 .  t - time at which to evaluate
3459 .  U - state at which to evaluate
3460 -  ctx - context
3461 
3462    Output Arguments:
3463 .  F - right hand side
3464 
3465    Level: intermediate
3466 
3467    Notes:
3468    This function is intended to be passed to TSSetRHSFunction() to evaluate the right hand side for linear problems.
3469    The matrix (and optionally the evaluation context) should be passed to TSSetRHSJacobian().
3470 
3471 .seealso: TSSetRHSFunction(), TSSetRHSJacobian(), TSComputeRHSJacobianConstant()
3472 @*/
3473 PetscErrorCode TSComputeRHSFunctionLinear(TS ts,PetscReal t,Vec U,Vec F,void *ctx)
3474 {
3475   PetscErrorCode ierr;
3476   Mat            Arhs,Brhs;
3477   MatStructure   flg2;
3478 
3479   PetscFunctionBegin;
3480   ierr = TSGetRHSMats_Private(ts,&Arhs,&Brhs);CHKERRQ(ierr);
3481   ierr = TSComputeRHSJacobian(ts,t,U,&Arhs,&Brhs,&flg2);CHKERRQ(ierr);
3482   ierr = MatMult(Arhs,U,F);CHKERRQ(ierr);
3483   PetscFunctionReturn(0);
3484 }
3485 
3486 #undef __FUNCT__
3487 #define __FUNCT__ "TSComputeRHSJacobianConstant"
3488 /*@C
3489    TSComputeRHSJacobianConstant - Reuses a Jacobian that is time-independent.
3490 
3491    Collective on TS
3492 
3493    Input Arguments:
3494 +  ts - time stepping context
3495 .  t - time at which to evaluate
3496 .  U - state at which to evaluate
3497 -  ctx - context
3498 
3499    Output Arguments:
3500 +  A - pointer to operator
3501 .  B - pointer to preconditioning matrix
3502 -  flg - matrix structure flag
3503 
3504    Level: intermediate
3505 
3506    Notes:
3507    This function is intended to be passed to TSSetRHSJacobian() to evaluate the Jacobian for linear time-independent problems.
3508 
3509 .seealso: TSSetRHSFunction(), TSSetRHSJacobian(), TSComputeRHSFunctionLinear()
3510 @*/
3511 PetscErrorCode TSComputeRHSJacobianConstant(TS ts,PetscReal t,Vec U,Mat *A,Mat *B,MatStructure *flg,void *ctx)
3512 {
3513   PetscFunctionBegin;
3514   *flg = SAME_PRECONDITIONER;
3515   PetscFunctionReturn(0);
3516 }
3517 
3518 #undef __FUNCT__
3519 #define __FUNCT__ "TSComputeIFunctionLinear"
3520 /*@C
3521    TSComputeIFunctionLinear - Evaluate the left hand side via the user-provided Jacobian, for linear problems only
3522 
3523    Collective on TS
3524 
3525    Input Arguments:
3526 +  ts - time stepping context
3527 .  t - time at which to evaluate
3528 .  U - state at which to evaluate
3529 .  Udot - time derivative of state vector
3530 -  ctx - context
3531 
3532    Output Arguments:
3533 .  F - left hand side
3534 
3535    Level: intermediate
3536 
3537    Notes:
3538    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
3539    user is required to write their own TSComputeIFunction.
3540    This function is intended to be passed to TSSetIFunction() to evaluate the left hand side for linear problems.
3541    The matrix (and optionally the evaluation context) should be passed to TSSetIJacobian().
3542 
3543 .seealso: TSSetIFunction(), TSSetIJacobian(), TSComputeIJacobianConstant()
3544 @*/
3545 PetscErrorCode TSComputeIFunctionLinear(TS ts,PetscReal t,Vec U,Vec Udot,Vec F,void *ctx)
3546 {
3547   PetscErrorCode ierr;
3548   Mat            A,B;
3549   MatStructure   flg2;
3550 
3551   PetscFunctionBegin;
3552   ierr = TSGetIJacobian(ts,&A,&B,NULL,NULL);CHKERRQ(ierr);
3553   ierr = TSComputeIJacobian(ts,t,U,Udot,1.0,&A,&B,&flg2,PETSC_TRUE);CHKERRQ(ierr);
3554   ierr = MatMult(A,Udot,F);CHKERRQ(ierr);
3555   PetscFunctionReturn(0);
3556 }
3557 
3558 #undef __FUNCT__
3559 #define __FUNCT__ "TSComputeIJacobianConstant"
3560 /*@C
3561    TSComputeIJacobianConstant - Reuses a time-independent for a semi-implicit DAE or ODE
3562 
3563    Collective on TS
3564 
3565    Input Arguments:
3566 +  ts - time stepping context
3567 .  t - time at which to evaluate
3568 .  U - state at which to evaluate
3569 .  Udot - time derivative of state vector
3570 .  shift - shift to apply
3571 -  ctx - context
3572 
3573    Output Arguments:
3574 +  A - pointer to operator
3575 .  B - pointer to preconditioning matrix
3576 -  flg - matrix structure flag
3577 
3578    Level: advanced
3579 
3580    Notes:
3581    This function is intended to be passed to TSSetIJacobian() to evaluate the Jacobian for linear time-independent problems.
3582 
3583    It is only appropriate for problems of the form
3584 
3585 $     M Udot = F(U,t)
3586 
3587   where M is constant and F is non-stiff.  The user must pass M to TSSetIJacobian().  The current implementation only
3588   works with IMEX time integration methods such as TSROSW and TSARKIMEX, since there is no support for de-constructing
3589   an implicit operator of the form
3590 
3591 $    shift*M + J
3592 
3593   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
3594   a copy of M or reassemble it when requested.
3595 
3596 .seealso: TSSetIFunction(), TSSetIJacobian(), TSComputeIFunctionLinear()
3597 @*/
3598 PetscErrorCode TSComputeIJacobianConstant(TS ts,PetscReal t,Vec U,Vec Udot,PetscReal shift,Mat *A,Mat *B,MatStructure *flg,void *ctx)
3599 {
3600   PetscErrorCode ierr;
3601 
3602   PetscFunctionBegin;
3603   ierr = MatScale(*A, shift / ts->ijacobian.shift);CHKERRQ(ierr);
3604   ts->ijacobian.shift = shift;
3605   *flg = SAME_PRECONDITIONER;
3606   PetscFunctionReturn(0);
3607 }
3608 
3609 #undef __FUNCT__
3610 #define __FUNCT__ "TSGetEquationType"
3611 /*@
3612    TSGetEquationType - Gets the type of the equation that TS is solving.
3613 
3614    Not Collective
3615 
3616    Input Parameter:
3617 .  ts - the TS context
3618 
3619    Output Parameter:
3620 .  equation_type - see TSEquationType
3621 
3622    Level: beginner
3623 
3624 .keywords: TS, equation type
3625 
3626 .seealso: TSSetEquationType(), TSEquationType
3627 @*/
3628 PetscErrorCode  TSGetEquationType(TS ts,TSEquationType *equation_type)
3629 {
3630   PetscFunctionBegin;
3631   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3632   PetscValidPointer(equation_type,2);
3633   *equation_type = ts->equation_type;
3634   PetscFunctionReturn(0);
3635 }
3636 
3637 #undef __FUNCT__
3638 #define __FUNCT__ "TSSetEquationType"
3639 /*@
3640    TSSetEquationType - Sets the type of the equation that TS is solving.
3641 
3642    Not Collective
3643 
3644    Input Parameter:
3645 +  ts - the TS context
3646 .  equation_type - see TSEquationType
3647 
3648    Level: advanced
3649 
3650 .keywords: TS, equation type
3651 
3652 .seealso: TSGetEquationType(), TSEquationType
3653 @*/
3654 PetscErrorCode  TSSetEquationType(TS ts,TSEquationType equation_type)
3655 {
3656   PetscFunctionBegin;
3657   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3658   ts->equation_type = equation_type;
3659   PetscFunctionReturn(0);
3660 }
3661 
3662 #undef __FUNCT__
3663 #define __FUNCT__ "TSGetConvergedReason"
3664 /*@
3665    TSGetConvergedReason - Gets the reason the TS iteration was stopped.
3666 
3667    Not Collective
3668 
3669    Input Parameter:
3670 .  ts - the TS context
3671 
3672    Output Parameter:
3673 .  reason - negative value indicates diverged, positive value converged, see TSConvergedReason or the
3674             manual pages for the individual convergence tests for complete lists
3675 
3676    Level: beginner
3677 
3678    Notes:
3679    Can only be called after the call to TSSolve() is complete.
3680 
3681 .keywords: TS, nonlinear, set, convergence, test
3682 
3683 .seealso: TSSetConvergenceTest(), TSConvergedReason
3684 @*/
3685 PetscErrorCode  TSGetConvergedReason(TS ts,TSConvergedReason *reason)
3686 {
3687   PetscFunctionBegin;
3688   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3689   PetscValidPointer(reason,2);
3690   *reason = ts->reason;
3691   PetscFunctionReturn(0);
3692 }
3693 
3694 #undef __FUNCT__
3695 #define __FUNCT__ "TSSetConvergedReason"
3696 /*@
3697    TSSetConvergedReason - Sets the reason for handling the convergence of TSSolve.
3698 
3699    Not Collective
3700 
3701    Input Parameter:
3702 +  ts - the TS context
3703 .  reason - negative value indicates diverged, positive value converged, see TSConvergedReason or the
3704             manual pages for the individual convergence tests for complete lists
3705 
3706    Level: advanced
3707 
3708    Notes:
3709    Can only be called during TSSolve() is active.
3710 
3711 .keywords: TS, nonlinear, set, convergence, test
3712 
3713 .seealso: TSConvergedReason
3714 @*/
3715 PetscErrorCode  TSSetConvergedReason(TS ts,TSConvergedReason reason)
3716 {
3717   PetscFunctionBegin;
3718   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3719   ts->reason = reason;
3720   PetscFunctionReturn(0);
3721 }
3722 
3723 #undef __FUNCT__
3724 #define __FUNCT__ "TSGetSolveTime"
3725 /*@
3726    TSGetSolveTime - Gets the time after a call to TSSolve()
3727 
3728    Not Collective
3729 
3730    Input Parameter:
3731 .  ts - the TS context
3732 
3733    Output Parameter:
3734 .  ftime - the final time. This time should correspond to the final time set with TSSetDuration()
3735 
3736    Level: beginner
3737 
3738    Notes:
3739    Can only be called after the call to TSSolve() is complete.
3740 
3741 .keywords: TS, nonlinear, set, convergence, test
3742 
3743 .seealso: TSSetConvergenceTest(), TSConvergedReason
3744 @*/
3745 PetscErrorCode  TSGetSolveTime(TS ts,PetscReal *ftime)
3746 {
3747   PetscFunctionBegin;
3748   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3749   PetscValidPointer(ftime,2);
3750   *ftime = ts->solvetime;
3751   PetscFunctionReturn(0);
3752 }
3753 
3754 #undef __FUNCT__
3755 #define __FUNCT__ "TSGetSNESIterations"
3756 /*@
3757    TSGetSNESIterations - Gets the total number of nonlinear iterations
3758    used by the time integrator.
3759 
3760    Not Collective
3761 
3762    Input Parameter:
3763 .  ts - TS context
3764 
3765    Output Parameter:
3766 .  nits - number of nonlinear iterations
3767 
3768    Notes:
3769    This counter is reset to zero for each successive call to TSSolve().
3770 
3771    Level: intermediate
3772 
3773 .keywords: TS, get, number, nonlinear, iterations
3774 
3775 .seealso:  TSGetKSPIterations()
3776 @*/
3777 PetscErrorCode TSGetSNESIterations(TS ts,PetscInt *nits)
3778 {
3779   PetscFunctionBegin;
3780   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3781   PetscValidIntPointer(nits,2);
3782   *nits = ts->snes_its;
3783   PetscFunctionReturn(0);
3784 }
3785 
3786 #undef __FUNCT__
3787 #define __FUNCT__ "TSGetKSPIterations"
3788 /*@
3789    TSGetKSPIterations - Gets the total number of linear iterations
3790    used by the time integrator.
3791 
3792    Not Collective
3793 
3794    Input Parameter:
3795 .  ts - TS context
3796 
3797    Output Parameter:
3798 .  lits - number of linear iterations
3799 
3800    Notes:
3801    This counter is reset to zero for each successive call to TSSolve().
3802 
3803    Level: intermediate
3804 
3805 .keywords: TS, get, number, linear, iterations
3806 
3807 .seealso:  TSGetSNESIterations(), SNESGetKSPIterations()
3808 @*/
3809 PetscErrorCode TSGetKSPIterations(TS ts,PetscInt *lits)
3810 {
3811   PetscFunctionBegin;
3812   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3813   PetscValidIntPointer(lits,2);
3814   *lits = ts->ksp_its;
3815   PetscFunctionReturn(0);
3816 }
3817 
3818 #undef __FUNCT__
3819 #define __FUNCT__ "TSGetStepRejections"
3820 /*@
3821    TSGetStepRejections - Gets the total number of rejected steps.
3822 
3823    Not Collective
3824 
3825    Input Parameter:
3826 .  ts - TS context
3827 
3828    Output Parameter:
3829 .  rejects - number of steps rejected
3830 
3831    Notes:
3832    This counter is reset to zero for each successive call to TSSolve().
3833 
3834    Level: intermediate
3835 
3836 .keywords: TS, get, number
3837 
3838 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetSNESFailures(), TSSetMaxSNESFailures(), TSSetErrorIfStepFails()
3839 @*/
3840 PetscErrorCode TSGetStepRejections(TS ts,PetscInt *rejects)
3841 {
3842   PetscFunctionBegin;
3843   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3844   PetscValidIntPointer(rejects,2);
3845   *rejects = ts->reject;
3846   PetscFunctionReturn(0);
3847 }
3848 
3849 #undef __FUNCT__
3850 #define __FUNCT__ "TSGetSNESFailures"
3851 /*@
3852    TSGetSNESFailures - Gets the total number of failed SNES solves
3853 
3854    Not Collective
3855 
3856    Input Parameter:
3857 .  ts - TS context
3858 
3859    Output Parameter:
3860 .  fails - number of failed nonlinear solves
3861 
3862    Notes:
3863    This counter is reset to zero for each successive call to TSSolve().
3864 
3865    Level: intermediate
3866 
3867 .keywords: TS, get, number
3868 
3869 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSSetMaxSNESFailures()
3870 @*/
3871 PetscErrorCode TSGetSNESFailures(TS ts,PetscInt *fails)
3872 {
3873   PetscFunctionBegin;
3874   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3875   PetscValidIntPointer(fails,2);
3876   *fails = ts->num_snes_failures;
3877   PetscFunctionReturn(0);
3878 }
3879 
3880 #undef __FUNCT__
3881 #define __FUNCT__ "TSSetMaxStepRejections"
3882 /*@
3883    TSSetMaxStepRejections - Sets the maximum number of step rejections before a step fails
3884 
3885    Not Collective
3886 
3887    Input Parameter:
3888 +  ts - TS context
3889 -  rejects - maximum number of rejected steps, pass -1 for unlimited
3890 
3891    Notes:
3892    The counter is reset to zero for each step
3893 
3894    Options Database Key:
3895  .  -ts_max_reject - Maximum number of step rejections before a step fails
3896 
3897    Level: intermediate
3898 
3899 .keywords: TS, set, maximum, number
3900 
3901 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxSNESFailures(), TSGetStepRejections(), TSGetSNESFailures(), TSSetErrorIfStepFails(), TSGetConvergedReason()
3902 @*/
3903 PetscErrorCode TSSetMaxStepRejections(TS ts,PetscInt rejects)
3904 {
3905   PetscFunctionBegin;
3906   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3907   ts->max_reject = rejects;
3908   PetscFunctionReturn(0);
3909 }
3910 
3911 #undef __FUNCT__
3912 #define __FUNCT__ "TSSetMaxSNESFailures"
3913 /*@
3914    TSSetMaxSNESFailures - Sets the maximum number of failed SNES solves
3915 
3916    Not Collective
3917 
3918    Input Parameter:
3919 +  ts - TS context
3920 -  fails - maximum number of failed nonlinear solves, pass -1 for unlimited
3921 
3922    Notes:
3923    The counter is reset to zero for each successive call to TSSolve().
3924 
3925    Options Database Key:
3926  .  -ts_max_snes_failures - Maximum number of nonlinear solve failures
3927 
3928    Level: intermediate
3929 
3930 .keywords: TS, set, maximum, number
3931 
3932 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSGetSNESFailures(), SNESGetConvergedReason(), TSGetConvergedReason()
3933 @*/
3934 PetscErrorCode TSSetMaxSNESFailures(TS ts,PetscInt fails)
3935 {
3936   PetscFunctionBegin;
3937   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3938   ts->max_snes_failures = fails;
3939   PetscFunctionReturn(0);
3940 }
3941 
3942 #undef __FUNCT__
3943 #define __FUNCT__ "TSSetErrorIfStepFails()"
3944 /*@
3945    TSSetErrorIfStepFails - Error if no step succeeds
3946 
3947    Not Collective
3948 
3949    Input Parameter:
3950 +  ts - TS context
3951 -  err - PETSC_TRUE to error if no step succeeds, PETSC_FALSE to return without failure
3952 
3953    Options Database Key:
3954  .  -ts_error_if_step_fails - Error if no step succeeds
3955 
3956    Level: intermediate
3957 
3958 .keywords: TS, set, error
3959 
3960 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSGetSNESFailures(), TSSetErrorIfStepFails(), TSGetConvergedReason()
3961 @*/
3962 PetscErrorCode TSSetErrorIfStepFails(TS ts,PetscBool err)
3963 {
3964   PetscFunctionBegin;
3965   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3966   ts->errorifstepfailed = err;
3967   PetscFunctionReturn(0);
3968 }
3969 
3970 #undef __FUNCT__
3971 #define __FUNCT__ "TSMonitorSolutionBinary"
3972 /*@C
3973    TSMonitorSolutionBinary - Monitors progress of the TS solvers by VecView() for the solution at each timestep. Normally the viewer is a binary file
3974 
3975    Collective on TS
3976 
3977    Input Parameters:
3978 +  ts - the TS context
3979 .  step - current time-step
3980 .  ptime - current time
3981 .  u - current state
3982 -  viewer - binary viewer
3983 
3984    Level: intermediate
3985 
3986 .keywords: TS,  vector, monitor, view
3987 
3988 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3989 @*/
3990 PetscErrorCode  TSMonitorSolutionBinary(TS ts,PetscInt step,PetscReal ptime,Vec u,void *viewer)
3991 {
3992   PetscErrorCode ierr;
3993   PetscViewer    v = (PetscViewer)viewer;
3994 
3995   PetscFunctionBegin;
3996   ierr = VecView(u,v);CHKERRQ(ierr);
3997   PetscFunctionReturn(0);
3998 }
3999 
4000 #undef __FUNCT__
4001 #define __FUNCT__ "TSMonitorSolutionVTK"
4002 /*@C
4003    TSMonitorSolutionVTK - Monitors progress of the TS solvers by VecView() for the solution at each timestep.
4004 
4005    Collective on TS
4006 
4007    Input Parameters:
4008 +  ts - the TS context
4009 .  step - current time-step
4010 .  ptime - current time
4011 .  u - current state
4012 -  filenametemplate - string containing a format specifier for the integer time step (e.g. %03D)
4013 
4014    Level: intermediate
4015 
4016    Notes:
4017    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.
4018    These are named according to the file name template.
4019 
4020    This function is normally passed as an argument to TSMonitorSet() along with TSMonitorSolutionVTKDestroy().
4021 
4022 .keywords: TS,  vector, monitor, view
4023 
4024 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
4025 @*/
4026 PetscErrorCode TSMonitorSolutionVTK(TS ts,PetscInt step,PetscReal ptime,Vec u,void *filenametemplate)
4027 {
4028   PetscErrorCode ierr;
4029   char           filename[PETSC_MAX_PATH_LEN];
4030   PetscViewer    viewer;
4031 
4032   PetscFunctionBegin;
4033   ierr = PetscSNPrintf(filename,sizeof(filename),(const char*)filenametemplate,step);CHKERRQ(ierr);
4034   ierr = PetscViewerVTKOpen(PetscObjectComm((PetscObject)ts),filename,FILE_MODE_WRITE,&viewer);CHKERRQ(ierr);
4035   ierr = VecView(u,viewer);CHKERRQ(ierr);
4036   ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
4037   PetscFunctionReturn(0);
4038 }
4039 
4040 #undef __FUNCT__
4041 #define __FUNCT__ "TSMonitorSolutionVTKDestroy"
4042 /*@C
4043    TSMonitorSolutionVTKDestroy - Destroy context for monitoring
4044 
4045    Collective on TS
4046 
4047    Input Parameters:
4048 .  filenametemplate - string containing a format specifier for the integer time step (e.g. %03D)
4049 
4050    Level: intermediate
4051 
4052    Note:
4053    This function is normally passed to TSMonitorSet() along with TSMonitorSolutionVTK().
4054 
4055 .keywords: TS,  vector, monitor, view
4056 
4057 .seealso: TSMonitorSet(), TSMonitorSolutionVTK()
4058 @*/
4059 PetscErrorCode TSMonitorSolutionVTKDestroy(void *filenametemplate)
4060 {
4061   PetscErrorCode ierr;
4062 
4063   PetscFunctionBegin;
4064   ierr = PetscFree(*(char**)filenametemplate);CHKERRQ(ierr);
4065   PetscFunctionReturn(0);
4066 }
4067 
4068 #undef __FUNCT__
4069 #define __FUNCT__ "TSGetAdapt"
4070 /*@
4071    TSGetAdapt - Get the adaptive controller context for the current method
4072 
4073    Collective on TS if controller has not been created yet
4074 
4075    Input Arguments:
4076 .  ts - time stepping context
4077 
4078    Output Arguments:
4079 .  adapt - adaptive controller
4080 
4081    Level: intermediate
4082 
4083 .seealso: TSAdapt, TSAdaptSetType(), TSAdaptChoose()
4084 @*/
4085 PetscErrorCode TSGetAdapt(TS ts,TSAdapt *adapt)
4086 {
4087   PetscErrorCode ierr;
4088 
4089   PetscFunctionBegin;
4090   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4091   PetscValidPointer(adapt,2);
4092   if (!ts->adapt) {
4093     ierr = TSAdaptCreate(PetscObjectComm((PetscObject)ts),&ts->adapt);CHKERRQ(ierr);
4094     ierr = PetscLogObjectParent(ts,ts->adapt);CHKERRQ(ierr);
4095     ierr = PetscObjectIncrementTabLevel((PetscObject)ts->adapt,(PetscObject)ts,1);CHKERRQ(ierr);
4096   }
4097   *adapt = ts->adapt;
4098   PetscFunctionReturn(0);
4099 }
4100 
4101 #undef __FUNCT__
4102 #define __FUNCT__ "TSSetTolerances"
4103 /*@
4104    TSSetTolerances - Set tolerances for local truncation error when using adaptive controller
4105 
4106    Logically Collective
4107 
4108    Input Arguments:
4109 +  ts - time integration context
4110 .  atol - scalar absolute tolerances, PETSC_DECIDE to leave current value
4111 .  vatol - vector of absolute tolerances or NULL, used in preference to atol if present
4112 .  rtol - scalar relative tolerances, PETSC_DECIDE to leave current value
4113 -  vrtol - vector of relative tolerances or NULL, used in preference to atol if present
4114 
4115    Level: beginner
4116 
4117 .seealso: TS, TSAdapt, TSVecNormWRMS(), TSGetTolerances()
4118 @*/
4119 PetscErrorCode TSSetTolerances(TS ts,PetscReal atol,Vec vatol,PetscReal rtol,Vec vrtol)
4120 {
4121   PetscErrorCode ierr;
4122 
4123   PetscFunctionBegin;
4124   if (atol != PETSC_DECIDE && atol != PETSC_DEFAULT) ts->atol = atol;
4125   if (vatol) {
4126     ierr = PetscObjectReference((PetscObject)vatol);CHKERRQ(ierr);
4127     ierr = VecDestroy(&ts->vatol);CHKERRQ(ierr);
4128 
4129     ts->vatol = vatol;
4130   }
4131   if (rtol != PETSC_DECIDE && rtol != PETSC_DEFAULT) ts->rtol = rtol;
4132   if (vrtol) {
4133     ierr = PetscObjectReference((PetscObject)vrtol);CHKERRQ(ierr);
4134     ierr = VecDestroy(&ts->vrtol);CHKERRQ(ierr);
4135 
4136     ts->vrtol = vrtol;
4137   }
4138   PetscFunctionReturn(0);
4139 }
4140 
4141 #undef __FUNCT__
4142 #define __FUNCT__ "TSGetTolerances"
4143 /*@
4144    TSGetTolerances - Get tolerances for local truncation error when using adaptive controller
4145 
4146    Logically Collective
4147 
4148    Input Arguments:
4149 .  ts - time integration context
4150 
4151    Output Arguments:
4152 +  atol - scalar absolute tolerances, NULL to ignore
4153 .  vatol - vector of absolute tolerances, NULL to ignore
4154 .  rtol - scalar relative tolerances, NULL to ignore
4155 -  vrtol - vector of relative tolerances, NULL to ignore
4156 
4157    Level: beginner
4158 
4159 .seealso: TS, TSAdapt, TSVecNormWRMS(), TSSetTolerances()
4160 @*/
4161 PetscErrorCode TSGetTolerances(TS ts,PetscReal *atol,Vec *vatol,PetscReal *rtol,Vec *vrtol)
4162 {
4163   PetscFunctionBegin;
4164   if (atol)  *atol  = ts->atol;
4165   if (vatol) *vatol = ts->vatol;
4166   if (rtol)  *rtol  = ts->rtol;
4167   if (vrtol) *vrtol = ts->vrtol;
4168   PetscFunctionReturn(0);
4169 }
4170 
4171 #undef __FUNCT__
4172 #define __FUNCT__ "TSErrorNormWRMS"
4173 /*@
4174    TSErrorNormWRMS - compute a weighted norm of the difference between a vector and the current state
4175 
4176    Collective on TS
4177 
4178    Input Arguments:
4179 +  ts - time stepping context
4180 -  Y - state vector to be compared to ts->vec_sol
4181 
4182    Output Arguments:
4183 .  norm - weighted norm, a value of 1.0 is considered small
4184 
4185    Level: developer
4186 
4187 .seealso: TSSetTolerances()
4188 @*/
4189 PetscErrorCode TSErrorNormWRMS(TS ts,Vec Y,PetscReal *norm)
4190 {
4191   PetscErrorCode    ierr;
4192   PetscInt          i,n,N;
4193   const PetscScalar *u,*y;
4194   Vec               U;
4195   PetscReal         sum,gsum;
4196 
4197   PetscFunctionBegin;
4198   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4199   PetscValidHeaderSpecific(Y,VEC_CLASSID,2);
4200   PetscValidPointer(norm,3);
4201   U = ts->vec_sol;
4202   PetscCheckSameTypeAndComm(U,1,Y,2);
4203   if (U == Y) SETERRQ(PetscObjectComm((PetscObject)U),PETSC_ERR_ARG_IDN,"Y cannot be the TS solution vector");
4204 
4205   ierr = VecGetSize(U,&N);CHKERRQ(ierr);
4206   ierr = VecGetLocalSize(U,&n);CHKERRQ(ierr);
4207   ierr = VecGetArrayRead(U,&u);CHKERRQ(ierr);
4208   ierr = VecGetArrayRead(Y,&y);CHKERRQ(ierr);
4209   sum  = 0.;
4210   if (ts->vatol && ts->vrtol) {
4211     const PetscScalar *atol,*rtol;
4212     ierr = VecGetArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4213     ierr = VecGetArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4214     for (i=0; i<n; i++) {
4215       PetscReal tol = PetscRealPart(atol[i]) + PetscRealPart(rtol[i]) * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4216       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4217     }
4218     ierr = VecRestoreArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4219     ierr = VecRestoreArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4220   } else if (ts->vatol) {       /* vector atol, scalar rtol */
4221     const PetscScalar *atol;
4222     ierr = VecGetArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4223     for (i=0; i<n; i++) {
4224       PetscReal tol = PetscRealPart(atol[i]) + ts->rtol * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4225       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4226     }
4227     ierr = VecRestoreArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4228   } else if (ts->vrtol) {       /* scalar atol, vector rtol */
4229     const PetscScalar *rtol;
4230     ierr = VecGetArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4231     for (i=0; i<n; i++) {
4232       PetscReal tol = ts->atol + PetscRealPart(rtol[i]) * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4233       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4234     }
4235     ierr = VecRestoreArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4236   } else {                      /* scalar atol, scalar rtol */
4237     for (i=0; i<n; i++) {
4238       PetscReal tol = ts->atol + ts->rtol * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4239       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4240     }
4241   }
4242   ierr = VecRestoreArrayRead(U,&u);CHKERRQ(ierr);
4243   ierr = VecRestoreArrayRead(Y,&y);CHKERRQ(ierr);
4244 
4245   ierr  = MPI_Allreduce(&sum,&gsum,1,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)ts));CHKERRQ(ierr);
4246   *norm = PetscSqrtReal(gsum / N);
4247   if (PetscIsInfOrNanScalar(*norm)) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_FP,"Infinite or not-a-number generated in norm");
4248   PetscFunctionReturn(0);
4249 }
4250 
4251 #undef __FUNCT__
4252 #define __FUNCT__ "TSSetCFLTimeLocal"
4253 /*@
4254    TSSetCFLTimeLocal - Set the local CFL constraint relative to forward Euler
4255 
4256    Logically Collective on TS
4257 
4258    Input Arguments:
4259 +  ts - time stepping context
4260 -  cfltime - maximum stable time step if using forward Euler (value can be different on each process)
4261 
4262    Note:
4263    After calling this function, the global CFL time can be obtained by calling TSGetCFLTime()
4264 
4265    Level: intermediate
4266 
4267 .seealso: TSGetCFLTime(), TSADAPTCFL
4268 @*/
4269 PetscErrorCode TSSetCFLTimeLocal(TS ts,PetscReal cfltime)
4270 {
4271   PetscFunctionBegin;
4272   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4273   ts->cfltime_local = cfltime;
4274   ts->cfltime       = -1.;
4275   PetscFunctionReturn(0);
4276 }
4277 
4278 #undef __FUNCT__
4279 #define __FUNCT__ "TSGetCFLTime"
4280 /*@
4281    TSGetCFLTime - Get the maximum stable time step according to CFL criteria applied to forward Euler
4282 
4283    Collective on TS
4284 
4285    Input Arguments:
4286 .  ts - time stepping context
4287 
4288    Output Arguments:
4289 .  cfltime - maximum stable time step for forward Euler
4290 
4291    Level: advanced
4292 
4293 .seealso: TSSetCFLTimeLocal()
4294 @*/
4295 PetscErrorCode TSGetCFLTime(TS ts,PetscReal *cfltime)
4296 {
4297   PetscErrorCode ierr;
4298 
4299   PetscFunctionBegin;
4300   if (ts->cfltime < 0) {
4301     ierr = MPI_Allreduce(&ts->cfltime_local,&ts->cfltime,1,MPIU_REAL,MPIU_MIN,PetscObjectComm((PetscObject)ts));CHKERRQ(ierr);
4302   }
4303   *cfltime = ts->cfltime;
4304   PetscFunctionReturn(0);
4305 }
4306 
4307 #undef __FUNCT__
4308 #define __FUNCT__ "TSVISetVariableBounds"
4309 /*@
4310    TSVISetVariableBounds - Sets the lower and upper bounds for the solution vector. xl <= x <= xu
4311 
4312    Input Parameters:
4313 .  ts   - the TS context.
4314 .  xl   - lower bound.
4315 .  xu   - upper bound.
4316 
4317    Notes:
4318    If this routine is not called then the lower and upper bounds are set to
4319    SNES_VI_NINF and SNES_VI_INF respectively during SNESSetUp().
4320 
4321    Level: advanced
4322 
4323 @*/
4324 PetscErrorCode TSVISetVariableBounds(TS ts, Vec xl, Vec xu)
4325 {
4326   PetscErrorCode ierr;
4327   SNES           snes;
4328 
4329   PetscFunctionBegin;
4330   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
4331   ierr = SNESVISetVariableBounds(snes,xl,xu);CHKERRQ(ierr);
4332   PetscFunctionReturn(0);
4333 }
4334 
4335 #if defined(PETSC_HAVE_MATLAB_ENGINE)
4336 #include <mex.h>
4337 
4338 typedef struct {char *funcname; mxArray *ctx;} TSMatlabContext;
4339 
4340 #undef __FUNCT__
4341 #define __FUNCT__ "TSComputeFunction_Matlab"
4342 /*
4343    TSComputeFunction_Matlab - Calls the function that has been set with
4344                          TSSetFunctionMatlab().
4345 
4346    Collective on TS
4347 
4348    Input Parameters:
4349 +  snes - the TS context
4350 -  u - input vector
4351 
4352    Output Parameter:
4353 .  y - function vector, as set by TSSetFunction()
4354 
4355    Notes:
4356    TSComputeFunction() is typically used within nonlinear solvers
4357    implementations, so most users would not generally call this routine
4358    themselves.
4359 
4360    Level: developer
4361 
4362 .keywords: TS, nonlinear, compute, function
4363 
4364 .seealso: TSSetFunction(), TSGetFunction()
4365 */
4366 PetscErrorCode  TSComputeFunction_Matlab(TS snes,PetscReal time,Vec u,Vec udot,Vec y, void *ctx)
4367 {
4368   PetscErrorCode  ierr;
4369   TSMatlabContext *sctx = (TSMatlabContext*)ctx;
4370   int             nlhs  = 1,nrhs = 7;
4371   mxArray         *plhs[1],*prhs[7];
4372   long long int   lx = 0,lxdot = 0,ly = 0,ls = 0;
4373 
4374   PetscFunctionBegin;
4375   PetscValidHeaderSpecific(snes,TS_CLASSID,1);
4376   PetscValidHeaderSpecific(u,VEC_CLASSID,3);
4377   PetscValidHeaderSpecific(udot,VEC_CLASSID,4);
4378   PetscValidHeaderSpecific(y,VEC_CLASSID,5);
4379   PetscCheckSameComm(snes,1,u,3);
4380   PetscCheckSameComm(snes,1,y,5);
4381 
4382   ierr = PetscMemcpy(&ls,&snes,sizeof(snes));CHKERRQ(ierr);
4383   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4384   ierr = PetscMemcpy(&lxdot,&udot,sizeof(udot));CHKERRQ(ierr);
4385   ierr = PetscMemcpy(&ly,&y,sizeof(u));CHKERRQ(ierr);
4386 
4387   prhs[0] =  mxCreateDoubleScalar((double)ls);
4388   prhs[1] =  mxCreateDoubleScalar(time);
4389   prhs[2] =  mxCreateDoubleScalar((double)lx);
4390   prhs[3] =  mxCreateDoubleScalar((double)lxdot);
4391   prhs[4] =  mxCreateDoubleScalar((double)ly);
4392   prhs[5] =  mxCreateString(sctx->funcname);
4393   prhs[6] =  sctx->ctx;
4394   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSComputeFunctionInternal");CHKERRQ(ierr);
4395   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4396   mxDestroyArray(prhs[0]);
4397   mxDestroyArray(prhs[1]);
4398   mxDestroyArray(prhs[2]);
4399   mxDestroyArray(prhs[3]);
4400   mxDestroyArray(prhs[4]);
4401   mxDestroyArray(prhs[5]);
4402   mxDestroyArray(plhs[0]);
4403   PetscFunctionReturn(0);
4404 }
4405 
4406 
4407 #undef __FUNCT__
4408 #define __FUNCT__ "TSSetFunctionMatlab"
4409 /*
4410    TSSetFunctionMatlab - Sets the function evaluation routine and function
4411    vector for use by the TS routines in solving ODEs
4412    equations from MATLAB. Here the function is a string containing the name of a MATLAB function
4413 
4414    Logically Collective on TS
4415 
4416    Input Parameters:
4417 +  ts - the TS context
4418 -  func - function evaluation routine
4419 
4420    Calling sequence of func:
4421 $    func (TS ts,PetscReal time,Vec u,Vec udot,Vec f,void *ctx);
4422 
4423    Level: beginner
4424 
4425 .keywords: TS, nonlinear, set, function
4426 
4427 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4428 */
4429 PetscErrorCode  TSSetFunctionMatlab(TS ts,const char *func,mxArray *ctx)
4430 {
4431   PetscErrorCode  ierr;
4432   TSMatlabContext *sctx;
4433 
4434   PetscFunctionBegin;
4435   /* currently sctx is memory bleed */
4436   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4437   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4438   /*
4439      This should work, but it doesn't
4440   sctx->ctx = ctx;
4441   mexMakeArrayPersistent(sctx->ctx);
4442   */
4443   sctx->ctx = mxDuplicateArray(ctx);
4444 
4445   ierr = TSSetIFunction(ts,NULL,TSComputeFunction_Matlab,sctx);CHKERRQ(ierr);
4446   PetscFunctionReturn(0);
4447 }
4448 
4449 #undef __FUNCT__
4450 #define __FUNCT__ "TSComputeJacobian_Matlab"
4451 /*
4452    TSComputeJacobian_Matlab - Calls the function that has been set with
4453                          TSSetJacobianMatlab().
4454 
4455    Collective on TS
4456 
4457    Input Parameters:
4458 +  ts - the TS context
4459 .  u - input vector
4460 .  A, B - the matrices
4461 -  ctx - user context
4462 
4463    Output Parameter:
4464 .  flag - structure of the matrix
4465 
4466    Level: developer
4467 
4468 .keywords: TS, nonlinear, compute, function
4469 
4470 .seealso: TSSetFunction(), TSGetFunction()
4471 @*/
4472 PetscErrorCode  TSComputeJacobian_Matlab(TS ts,PetscReal time,Vec u,Vec udot,PetscReal shift,Mat *A,Mat *B,MatStructure *flag, void *ctx)
4473 {
4474   PetscErrorCode  ierr;
4475   TSMatlabContext *sctx = (TSMatlabContext*)ctx;
4476   int             nlhs  = 2,nrhs = 9;
4477   mxArray         *plhs[2],*prhs[9];
4478   long long int   lx = 0,lxdot = 0,lA = 0,ls = 0, lB = 0;
4479 
4480   PetscFunctionBegin;
4481   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4482   PetscValidHeaderSpecific(u,VEC_CLASSID,3);
4483 
4484   /* call Matlab function in ctx with arguments u and y */
4485 
4486   ierr = PetscMemcpy(&ls,&ts,sizeof(ts));CHKERRQ(ierr);
4487   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4488   ierr = PetscMemcpy(&lxdot,&udot,sizeof(u));CHKERRQ(ierr);
4489   ierr = PetscMemcpy(&lA,A,sizeof(u));CHKERRQ(ierr);
4490   ierr = PetscMemcpy(&lB,B,sizeof(u));CHKERRQ(ierr);
4491 
4492   prhs[0] =  mxCreateDoubleScalar((double)ls);
4493   prhs[1] =  mxCreateDoubleScalar((double)time);
4494   prhs[2] =  mxCreateDoubleScalar((double)lx);
4495   prhs[3] =  mxCreateDoubleScalar((double)lxdot);
4496   prhs[4] =  mxCreateDoubleScalar((double)shift);
4497   prhs[5] =  mxCreateDoubleScalar((double)lA);
4498   prhs[6] =  mxCreateDoubleScalar((double)lB);
4499   prhs[7] =  mxCreateString(sctx->funcname);
4500   prhs[8] =  sctx->ctx;
4501   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSComputeJacobianInternal");CHKERRQ(ierr);
4502   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4503   *flag   =  (MatStructure) mxGetScalar(plhs[1]);CHKERRQ(ierr);
4504   mxDestroyArray(prhs[0]);
4505   mxDestroyArray(prhs[1]);
4506   mxDestroyArray(prhs[2]);
4507   mxDestroyArray(prhs[3]);
4508   mxDestroyArray(prhs[4]);
4509   mxDestroyArray(prhs[5]);
4510   mxDestroyArray(prhs[6]);
4511   mxDestroyArray(prhs[7]);
4512   mxDestroyArray(plhs[0]);
4513   mxDestroyArray(plhs[1]);
4514   PetscFunctionReturn(0);
4515 }
4516 
4517 
4518 #undef __FUNCT__
4519 #define __FUNCT__ "TSSetJacobianMatlab"
4520 /*
4521    TSSetJacobianMatlab - Sets the Jacobian function evaluation routine and two empty Jacobian matrices
4522    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
4523 
4524    Logically Collective on TS
4525 
4526    Input Parameters:
4527 +  ts - the TS context
4528 .  A,B - Jacobian matrices
4529 .  func - function evaluation routine
4530 -  ctx - user context
4531 
4532    Calling sequence of func:
4533 $    flag = func (TS ts,PetscReal time,Vec u,Vec udot,Mat A,Mat B,void *ctx);
4534 
4535 
4536    Level: developer
4537 
4538 .keywords: TS, nonlinear, set, function
4539 
4540 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4541 */
4542 PetscErrorCode  TSSetJacobianMatlab(TS ts,Mat A,Mat B,const char *func,mxArray *ctx)
4543 {
4544   PetscErrorCode  ierr;
4545   TSMatlabContext *sctx;
4546 
4547   PetscFunctionBegin;
4548   /* currently sctx is memory bleed */
4549   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4550   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4551   /*
4552      This should work, but it doesn't
4553   sctx->ctx = ctx;
4554   mexMakeArrayPersistent(sctx->ctx);
4555   */
4556   sctx->ctx = mxDuplicateArray(ctx);
4557 
4558   ierr = TSSetIJacobian(ts,A,B,TSComputeJacobian_Matlab,sctx);CHKERRQ(ierr);
4559   PetscFunctionReturn(0);
4560 }
4561 
4562 #undef __FUNCT__
4563 #define __FUNCT__ "TSMonitor_Matlab"
4564 /*
4565    TSMonitor_Matlab - Calls the function that has been set with TSMonitorSetMatlab().
4566 
4567    Collective on TS
4568 
4569 .seealso: TSSetFunction(), TSGetFunction()
4570 @*/
4571 PetscErrorCode  TSMonitor_Matlab(TS ts,PetscInt it, PetscReal time,Vec u, void *ctx)
4572 {
4573   PetscErrorCode  ierr;
4574   TSMatlabContext *sctx = (TSMatlabContext*)ctx;
4575   int             nlhs  = 1,nrhs = 6;
4576   mxArray         *plhs[1],*prhs[6];
4577   long long int   lx = 0,ls = 0;
4578 
4579   PetscFunctionBegin;
4580   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4581   PetscValidHeaderSpecific(u,VEC_CLASSID,4);
4582 
4583   ierr = PetscMemcpy(&ls,&ts,sizeof(ts));CHKERRQ(ierr);
4584   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4585 
4586   prhs[0] =  mxCreateDoubleScalar((double)ls);
4587   prhs[1] =  mxCreateDoubleScalar((double)it);
4588   prhs[2] =  mxCreateDoubleScalar((double)time);
4589   prhs[3] =  mxCreateDoubleScalar((double)lx);
4590   prhs[4] =  mxCreateString(sctx->funcname);
4591   prhs[5] =  sctx->ctx;
4592   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSMonitorInternal");CHKERRQ(ierr);
4593   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4594   mxDestroyArray(prhs[0]);
4595   mxDestroyArray(prhs[1]);
4596   mxDestroyArray(prhs[2]);
4597   mxDestroyArray(prhs[3]);
4598   mxDestroyArray(prhs[4]);
4599   mxDestroyArray(plhs[0]);
4600   PetscFunctionReturn(0);
4601 }
4602 
4603 
4604 #undef __FUNCT__
4605 #define __FUNCT__ "TSMonitorSetMatlab"
4606 /*
4607    TSMonitorSetMatlab - Sets the monitor function from Matlab
4608 
4609    Level: developer
4610 
4611 .keywords: TS, nonlinear, set, function
4612 
4613 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4614 */
4615 PetscErrorCode  TSMonitorSetMatlab(TS ts,const char *func,mxArray *ctx)
4616 {
4617   PetscErrorCode  ierr;
4618   TSMatlabContext *sctx;
4619 
4620   PetscFunctionBegin;
4621   /* currently sctx is memory bleed */
4622   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4623   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4624   /*
4625      This should work, but it doesn't
4626   sctx->ctx = ctx;
4627   mexMakeArrayPersistent(sctx->ctx);
4628   */
4629   sctx->ctx = mxDuplicateArray(ctx);
4630 
4631   ierr = TSMonitorSet(ts,TSMonitor_Matlab,sctx,NULL);CHKERRQ(ierr);
4632   PetscFunctionReturn(0);
4633 }
4634 #endif
4635 
4636 
4637 
4638 #undef __FUNCT__
4639 #define __FUNCT__ "TSMonitorLGSolution"
4640 /*@C
4641    TSMonitorLGSolution - Monitors progress of the TS solvers by plotting each component of the solution vector
4642        in a time based line graph
4643 
4644    Collective on TS
4645 
4646    Input Parameters:
4647 +  ts - the TS context
4648 .  step - current time-step
4649 .  ptime - current time
4650 -  lg - a line graph object
4651 
4652    Level: intermediate
4653 
4654     Notes: each process in a parallel run displays its component solutions in a separate window
4655 
4656 .keywords: TS,  vector, monitor, view
4657 
4658 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
4659 @*/
4660 PetscErrorCode  TSMonitorLGSolution(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
4661 {
4662   PetscErrorCode    ierr;
4663   TSMonitorLGCtx    ctx = (TSMonitorLGCtx)dummy;
4664   const PetscScalar *yy;
4665   PetscInt          dim;
4666 
4667   PetscFunctionBegin;
4668   if (!step) {
4669     PetscDrawAxis axis;
4670     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4671     ierr = PetscDrawAxisSetLabels(axis,"Solution as function of time","Time","Solution");CHKERRQ(ierr);
4672     ierr = VecGetLocalSize(u,&dim);CHKERRQ(ierr);
4673     ierr = PetscDrawLGSetDimension(ctx->lg,dim);CHKERRQ(ierr);
4674     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4675   }
4676   ierr = VecGetArrayRead(u,&yy);CHKERRQ(ierr);
4677 #if defined(PETSC_USE_COMPLEX)
4678   {
4679     PetscReal *yreal;
4680     PetscInt  i,n;
4681     ierr = VecGetLocalSize(u,&n);CHKERRQ(ierr);
4682     ierr = PetscMalloc(n*sizeof(PetscReal),&yreal);CHKERRQ(ierr);
4683     for (i=0; i<n; i++) yreal[i] = PetscRealPart(yy[i]);
4684     ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yreal);CHKERRQ(ierr);
4685     ierr = PetscFree(yreal);CHKERRQ(ierr);
4686   }
4687 #else
4688   ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yy);CHKERRQ(ierr);
4689 #endif
4690   ierr = VecRestoreArrayRead(u,&yy);CHKERRQ(ierr);
4691   if (((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason)) {
4692     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4693   }
4694   PetscFunctionReturn(0);
4695 }
4696 
4697 #undef __FUNCT__
4698 #define __FUNCT__ "TSMonitorLGError"
4699 /*@C
4700    TSMonitorLGError - Monitors progress of the TS solvers by plotting each component of the solution vector
4701        in a time based line graph
4702 
4703    Collective on TS
4704 
4705    Input Parameters:
4706 +  ts - the TS context
4707 .  step - current time-step
4708 .  ptime - current time
4709 -  lg - a line graph object
4710 
4711    Level: intermediate
4712 
4713    Notes:
4714    Only for sequential solves.
4715 
4716    The user must provide the solution using TSSetSolutionFunction() to use this monitor.
4717 
4718    Options Database Keys:
4719 .  -ts_monitor_lg_error - create a graphical monitor of error history
4720 
4721 .keywords: TS,  vector, monitor, view
4722 
4723 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSSetSolutionFunction()
4724 @*/
4725 PetscErrorCode  TSMonitorLGError(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
4726 {
4727   PetscErrorCode    ierr;
4728   TSMonitorLGCtx    ctx = (TSMonitorLGCtx)dummy;
4729   const PetscScalar *yy;
4730   Vec               y;
4731   PetscInt          dim;
4732 
4733   PetscFunctionBegin;
4734   if (!step) {
4735     PetscDrawAxis axis;
4736     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4737     ierr = PetscDrawAxisSetLabels(axis,"Error in solution as function of time","Time","Solution");CHKERRQ(ierr);
4738     ierr = VecGetLocalSize(u,&dim);CHKERRQ(ierr);
4739     ierr = PetscDrawLGSetDimension(ctx->lg,dim);CHKERRQ(ierr);
4740     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4741   }
4742   ierr = VecDuplicate(u,&y);CHKERRQ(ierr);
4743   ierr = TSComputeSolutionFunction(ts,ptime,y);CHKERRQ(ierr);
4744   ierr = VecAXPY(y,-1.0,u);CHKERRQ(ierr);
4745   ierr = VecGetArrayRead(y,&yy);CHKERRQ(ierr);
4746 #if defined(PETSC_USE_COMPLEX)
4747   {
4748     PetscReal *yreal;
4749     PetscInt  i,n;
4750     ierr = VecGetLocalSize(y,&n);CHKERRQ(ierr);
4751     ierr = PetscMalloc(n*sizeof(PetscReal),&yreal);CHKERRQ(ierr);
4752     for (i=0; i<n; i++) yreal[i] = PetscRealPart(yy[i]);
4753     ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yreal);CHKERRQ(ierr);
4754     ierr = PetscFree(yreal);CHKERRQ(ierr);
4755   }
4756 #else
4757   ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yy);CHKERRQ(ierr);
4758 #endif
4759   ierr = VecRestoreArrayRead(y,&yy);CHKERRQ(ierr);
4760   ierr = VecDestroy(&y);CHKERRQ(ierr);
4761   if (((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason)) {
4762     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4763   }
4764   PetscFunctionReturn(0);
4765 }
4766 
4767 #undef __FUNCT__
4768 #define __FUNCT__ "TSMonitorLGSNESIterations"
4769 PetscErrorCode TSMonitorLGSNESIterations(TS ts,PetscInt n,PetscReal ptime,Vec v,void *monctx)
4770 {
4771   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
4772   PetscReal      x   = ptime,y;
4773   PetscErrorCode ierr;
4774   PetscInt       its;
4775 
4776   PetscFunctionBegin;
4777   if (!n) {
4778     PetscDrawAxis axis;
4779 
4780     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4781     ierr = PetscDrawAxisSetLabels(axis,"Nonlinear iterations as function of time","Time","SNES Iterations");CHKERRQ(ierr);
4782     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4783 
4784     ctx->snes_its = 0;
4785   }
4786   ierr = TSGetSNESIterations(ts,&its);CHKERRQ(ierr);
4787   y    = its - ctx->snes_its;
4788   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
4789   if (((ctx->howoften > 0) && (!(n % ctx->howoften)) && (n > -1)) || ((ctx->howoften == -1) && (n == -1))) {
4790     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4791   }
4792   ctx->snes_its = its;
4793   PetscFunctionReturn(0);
4794 }
4795 
4796 #undef __FUNCT__
4797 #define __FUNCT__ "TSMonitorLGKSPIterations"
4798 PetscErrorCode TSMonitorLGKSPIterations(TS ts,PetscInt n,PetscReal ptime,Vec v,void *monctx)
4799 {
4800   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
4801   PetscReal      x   = ptime,y;
4802   PetscErrorCode ierr;
4803   PetscInt       its;
4804 
4805   PetscFunctionBegin;
4806   if (!n) {
4807     PetscDrawAxis axis;
4808 
4809     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4810     ierr = PetscDrawAxisSetLabels(axis,"Linear iterations as function of time","Time","KSP Iterations");CHKERRQ(ierr);
4811     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4812 
4813     ctx->ksp_its = 0;
4814   }
4815   ierr = TSGetKSPIterations(ts,&its);CHKERRQ(ierr);
4816   y    = its - ctx->ksp_its;
4817   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
4818   if (((ctx->howoften > 0) && (!(n % ctx->howoften)) && (n > -1)) || ((ctx->howoften == -1) && (n == -1))) {
4819     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4820   }
4821   ctx->ksp_its = its;
4822   PetscFunctionReturn(0);
4823 }
4824 
4825 #undef __FUNCT__
4826 #define __FUNCT__ "TSComputeLinearStability"
4827 /*@
4828    TSComputeLinearStability - computes the linear stability function at a point
4829 
4830    Collective on TS and Vec
4831 
4832    Input Parameters:
4833 +  ts - the TS context
4834 -  xr,xi - real and imaginary part of input arguments
4835 
4836    Output Parameters:
4837 .  yr,yi - real and imaginary part of function value
4838 
4839    Level: developer
4840 
4841 .keywords: TS, compute
4842 
4843 .seealso: TSSetRHSFunction(), TSComputeIFunction()
4844 @*/
4845 PetscErrorCode TSComputeLinearStability(TS ts,PetscReal xr,PetscReal xi,PetscReal *yr,PetscReal *yi)
4846 {
4847   PetscErrorCode ierr;
4848 
4849   PetscFunctionBegin;
4850   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4851   if (!ts->ops->linearstability) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"Linearized stability function not provided for this method");
4852   ierr = (*ts->ops->linearstability)(ts,xr,xi,yr,yi);CHKERRQ(ierr);
4853   PetscFunctionReturn(0);
4854 }
4855 
4856 #undef __FUNCT__
4857 #define __FUNCT__ "TSRollBack"
4858 /*@
4859    TSRollBack - Rolls back one time step
4860 
4861    Collective on TS
4862 
4863    Input Parameter:
4864 .  ts - the TS context obtained from TSCreate()
4865 
4866    Level: advanced
4867 
4868 .keywords: TS, timestep, rollback
4869 
4870 .seealso: TSCreate(), TSSetUp(), TSDestroy(), TSSolve(), TSSetPreStep(), TSSetPreStage(), TSInterpolate()
4871 @*/
4872 PetscErrorCode  TSRollBack(TS ts)
4873 {
4874   PetscErrorCode ierr;
4875 
4876   PetscFunctionBegin;
4877   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
4878 
4879   if (!ts->ops->rollback) SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"TSRollBack not implemented for type '%s'",((PetscObject)ts)->type_name);
4880   ierr = (*ts->ops->rollback)(ts);CHKERRQ(ierr);
4881   ts->time_step = ts->ptime - ts->ptime_prev;
4882   ts->ptime = ts->ptime_prev;
4883   PetscFunctionReturn(0);
4884 }
4885