xref: /petsc/src/ts/interface/ts.c (revision a0931e03ada338ad224fa7b2b72c49aa35bdd205)
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_SAWS)
1280 #include <petscviewersaws.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_SAWS)
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_SAWS)
1336   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSAWS,&isams);CHKERRQ(ierr);
1337 #endif
1338   if (iascii) {
1339     ierr = PetscObjectPrintClassNamePrefixType((PetscObject)ts,viewer);CHKERRQ(ierr);
1340     ierr = PetscViewerASCIIPrintf(viewer,"  maximum steps=%D\n",ts->max_steps);CHKERRQ(ierr);
1341     ierr = PetscViewerASCIIPrintf(viewer,"  maximum time=%G\n",ts->max_time);CHKERRQ(ierr);
1342     if (ts->problem_type == TS_NONLINEAR) {
1343       ierr = PetscViewerASCIIPrintf(viewer,"  total number of nonlinear solver iterations=%D\n",ts->snes_its);CHKERRQ(ierr);
1344       ierr = PetscViewerASCIIPrintf(viewer,"  total number of nonlinear solve failures=%D\n",ts->num_snes_failures);CHKERRQ(ierr);
1345     }
1346     ierr = PetscViewerASCIIPrintf(viewer,"  total number of linear solver iterations=%D\n",ts->ksp_its);CHKERRQ(ierr);
1347     ierr = PetscViewerASCIIPrintf(viewer,"  total number of rejected steps=%D\n",ts->reject);CHKERRQ(ierr);
1348     ierr = DMGetDMTS(ts->dm,&sdm);CHKERRQ(ierr);
1349     ierr = DMTSView(sdm,viewer);CHKERRQ(ierr);
1350     if (ts->ops->view) {
1351       ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
1352       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1353       ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
1354     }
1355   } else if (isstring) {
1356     ierr = TSGetType(ts,&type);CHKERRQ(ierr);
1357     ierr = PetscViewerStringSPrintf(viewer," %-7.7s",type);CHKERRQ(ierr);
1358   } else if (isbinary) {
1359     PetscInt    classid = TS_FILE_CLASSID;
1360     MPI_Comm    comm;
1361     PetscMPIInt rank;
1362     char        type[256];
1363 
1364     ierr = PetscObjectGetComm((PetscObject)ts,&comm);CHKERRQ(ierr);
1365     ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
1366     if (!rank) {
1367       ierr = PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT,PETSC_FALSE);CHKERRQ(ierr);
1368       ierr = PetscStrncpy(type,((PetscObject)ts)->type_name,256);CHKERRQ(ierr);
1369       ierr = PetscViewerBinaryWrite(viewer,type,256,PETSC_CHAR,PETSC_FALSE);CHKERRQ(ierr);
1370     }
1371     if (ts->ops->view) {
1372       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1373     }
1374     ierr = DMView(ts->dm,viewer);CHKERRQ(ierr);
1375     ierr = VecView(ts->vec_sol,viewer);CHKERRQ(ierr);
1376     ierr = DMGetDMTS(ts->dm,&sdm);CHKERRQ(ierr);
1377     ierr = DMTSView(sdm,viewer);CHKERRQ(ierr);
1378   } else if (isdraw) {
1379     PetscDraw draw;
1380     char      str[36];
1381     PetscReal x,y,bottom,h;
1382 
1383     ierr   = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr);
1384     ierr   = PetscDrawGetCurrentPoint(draw,&x,&y);CHKERRQ(ierr);
1385     ierr   = PetscStrcpy(str,"TS: ");CHKERRQ(ierr);
1386     ierr   = PetscStrcat(str,((PetscObject)ts)->type_name);CHKERRQ(ierr);
1387     ierr   = PetscDrawBoxedString(draw,x,y,PETSC_DRAW_BLACK,PETSC_DRAW_BLACK,str,NULL,&h);CHKERRQ(ierr);
1388     bottom = y - h;
1389     ierr   = PetscDrawPushCurrentPoint(draw,x,bottom);CHKERRQ(ierr);
1390     if (ts->ops->view) {
1391       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1392     }
1393     ierr = PetscDrawPopCurrentPoint(draw);CHKERRQ(ierr);
1394 #if defined(PETSC_HAVE_SAWS)
1395   } else if (isams) {
1396     if (!((PetscObject)ts)->amsmem) {
1397       char       dir[1024];
1398       const char *name;
1399 
1400       ierr = PetscObjectGetName((PetscObject)ts,&name);CHKERRQ(ierr);
1401       ierr = PetscObjectViewSAWs((PetscObject)ts,viewer);CHKERRQ(ierr);
1402       ierr = PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/time_step",name);CHKERRQ(ierr);
1403       PetscStackCallSAWs(SAWs_Register,(dir,&ts->steps,1,SAWs_READ,SAWs_INT));
1404       ierr = PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/time",name);CHKERRQ(ierr);
1405       PetscStackCallSAWs(SAWs_Register,(dir,&ts->ptime,1,SAWs_READ,SAWs_DOUBLE));
1406     }
1407     if (ts->ops->view) {
1408       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1409     }
1410 #endif
1411   }
1412 
1413   ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
1414   ierr = PetscObjectTypeCompare((PetscObject)ts,TSSUNDIALS,&isundials);CHKERRQ(ierr);
1415   ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
1416   PetscFunctionReturn(0);
1417 }
1418 
1419 
1420 #undef __FUNCT__
1421 #define __FUNCT__ "TSSetApplicationContext"
1422 /*@
1423    TSSetApplicationContext - Sets an optional user-defined context for
1424    the timesteppers.
1425 
1426    Logically Collective on TS
1427 
1428    Input Parameters:
1429 +  ts - the TS context obtained from TSCreate()
1430 -  usrP - optional user context
1431 
1432    Level: intermediate
1433 
1434 .keywords: TS, timestep, set, application, context
1435 
1436 .seealso: TSGetApplicationContext()
1437 @*/
1438 PetscErrorCode  TSSetApplicationContext(TS ts,void *usrP)
1439 {
1440   PetscFunctionBegin;
1441   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1442   ts->user = usrP;
1443   PetscFunctionReturn(0);
1444 }
1445 
1446 #undef __FUNCT__
1447 #define __FUNCT__ "TSGetApplicationContext"
1448 /*@
1449     TSGetApplicationContext - Gets the user-defined context for the
1450     timestepper.
1451 
1452     Not Collective
1453 
1454     Input Parameter:
1455 .   ts - the TS context obtained from TSCreate()
1456 
1457     Output Parameter:
1458 .   usrP - user context
1459 
1460     Level: intermediate
1461 
1462 .keywords: TS, timestep, get, application, context
1463 
1464 .seealso: TSSetApplicationContext()
1465 @*/
1466 PetscErrorCode  TSGetApplicationContext(TS ts,void *usrP)
1467 {
1468   PetscFunctionBegin;
1469   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1470   *(void**)usrP = ts->user;
1471   PetscFunctionReturn(0);
1472 }
1473 
1474 #undef __FUNCT__
1475 #define __FUNCT__ "TSGetTimeStepNumber"
1476 /*@
1477    TSGetTimeStepNumber - Gets the number of time steps completed.
1478 
1479    Not Collective
1480 
1481    Input Parameter:
1482 .  ts - the TS context obtained from TSCreate()
1483 
1484    Output Parameter:
1485 .  iter - number of steps completed so far
1486 
1487    Level: intermediate
1488 
1489 .keywords: TS, timestep, get, iteration, number
1490 .seealso: TSGetTime(), TSGetTimeStep(), TSSetPreStep(), TSSetPreStage(), TSSetPostStep()
1491 @*/
1492 PetscErrorCode  TSGetTimeStepNumber(TS ts,PetscInt *iter)
1493 {
1494   PetscFunctionBegin;
1495   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1496   PetscValidIntPointer(iter,2);
1497   *iter = ts->steps;
1498   PetscFunctionReturn(0);
1499 }
1500 
1501 #undef __FUNCT__
1502 #define __FUNCT__ "TSSetInitialTimeStep"
1503 /*@
1504    TSSetInitialTimeStep - Sets the initial timestep to be used,
1505    as well as the initial time.
1506 
1507    Logically Collective on TS
1508 
1509    Input Parameters:
1510 +  ts - the TS context obtained from TSCreate()
1511 .  initial_time - the initial time
1512 -  time_step - the size of the timestep
1513 
1514    Level: intermediate
1515 
1516 .seealso: TSSetTimeStep(), TSGetTimeStep()
1517 
1518 .keywords: TS, set, initial, timestep
1519 @*/
1520 PetscErrorCode  TSSetInitialTimeStep(TS ts,PetscReal initial_time,PetscReal time_step)
1521 {
1522   PetscErrorCode ierr;
1523 
1524   PetscFunctionBegin;
1525   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1526   ierr = TSSetTimeStep(ts,time_step);CHKERRQ(ierr);
1527   ierr = TSSetTime(ts,initial_time);CHKERRQ(ierr);
1528   PetscFunctionReturn(0);
1529 }
1530 
1531 #undef __FUNCT__
1532 #define __FUNCT__ "TSSetTimeStep"
1533 /*@
1534    TSSetTimeStep - Allows one to reset the timestep at any time,
1535    useful for simple pseudo-timestepping codes.
1536 
1537    Logically Collective on TS
1538 
1539    Input Parameters:
1540 +  ts - the TS context obtained from TSCreate()
1541 -  time_step - the size of the timestep
1542 
1543    Level: intermediate
1544 
1545 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
1546 
1547 .keywords: TS, set, timestep
1548 @*/
1549 PetscErrorCode  TSSetTimeStep(TS ts,PetscReal time_step)
1550 {
1551   PetscFunctionBegin;
1552   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1553   PetscValidLogicalCollectiveReal(ts,time_step,2);
1554   ts->time_step      = time_step;
1555   ts->time_step_orig = time_step;
1556   PetscFunctionReturn(0);
1557 }
1558 
1559 #undef __FUNCT__
1560 #define __FUNCT__ "TSSetExactFinalTime"
1561 /*@
1562    TSSetExactFinalTime - Determines whether to adapt the final time step to
1563      match the exact final time, interpolate solution to the exact final time,
1564      or just return at the final time TS computed.
1565 
1566   Logically Collective on TS
1567 
1568    Input Parameter:
1569 +   ts - the time-step context
1570 -   eftopt - exact final time option
1571 
1572    Level: beginner
1573 
1574 .seealso: TSExactFinalTimeOption
1575 @*/
1576 PetscErrorCode  TSSetExactFinalTime(TS ts,TSExactFinalTimeOption eftopt)
1577 {
1578   PetscFunctionBegin;
1579   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1580   PetscValidLogicalCollectiveEnum(ts,eftopt,2);
1581   ts->exact_final_time = eftopt;
1582   PetscFunctionReturn(0);
1583 }
1584 
1585 #undef __FUNCT__
1586 #define __FUNCT__ "TSGetTimeStep"
1587 /*@
1588    TSGetTimeStep - Gets the current timestep size.
1589 
1590    Not Collective
1591 
1592    Input Parameter:
1593 .  ts - the TS context obtained from TSCreate()
1594 
1595    Output Parameter:
1596 .  dt - the current timestep size
1597 
1598    Level: intermediate
1599 
1600 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
1601 
1602 .keywords: TS, get, timestep
1603 @*/
1604 PetscErrorCode  TSGetTimeStep(TS ts,PetscReal *dt)
1605 {
1606   PetscFunctionBegin;
1607   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1608   PetscValidRealPointer(dt,2);
1609   *dt = ts->time_step;
1610   PetscFunctionReturn(0);
1611 }
1612 
1613 #undef __FUNCT__
1614 #define __FUNCT__ "TSGetSolution"
1615 /*@
1616    TSGetSolution - Returns the solution at the present timestep. It
1617    is valid to call this routine inside the function that you are evaluating
1618    in order to move to the new timestep. This vector not changed until
1619    the solution at the next timestep has been calculated.
1620 
1621    Not Collective, but Vec returned is parallel if TS is parallel
1622 
1623    Input Parameter:
1624 .  ts - the TS context obtained from TSCreate()
1625 
1626    Output Parameter:
1627 .  v - the vector containing the solution
1628 
1629    Level: intermediate
1630 
1631 .seealso: TSGetTimeStep()
1632 
1633 .keywords: TS, timestep, get, solution
1634 @*/
1635 PetscErrorCode  TSGetSolution(TS ts,Vec *v)
1636 {
1637   PetscFunctionBegin;
1638   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1639   PetscValidPointer(v,2);
1640   *v = ts->vec_sol;
1641   PetscFunctionReturn(0);
1642 }
1643 
1644 /* ----- Routines to initialize and destroy a timestepper ---- */
1645 #undef __FUNCT__
1646 #define __FUNCT__ "TSSetProblemType"
1647 /*@
1648   TSSetProblemType - Sets the type of problem to be solved.
1649 
1650   Not collective
1651 
1652   Input Parameters:
1653 + ts   - The TS
1654 - type - One of TS_LINEAR, TS_NONLINEAR where these types refer to problems of the forms
1655 .vb
1656          U_t - A U = 0      (linear)
1657          U_t - A(t) U = 0   (linear)
1658          F(t,U,U_t) = 0     (nonlinear)
1659 .ve
1660 
1661    Level: beginner
1662 
1663 .keywords: TS, problem type
1664 .seealso: TSSetUp(), TSProblemType, TS
1665 @*/
1666 PetscErrorCode  TSSetProblemType(TS ts, TSProblemType type)
1667 {
1668   PetscErrorCode ierr;
1669 
1670   PetscFunctionBegin;
1671   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
1672   ts->problem_type = type;
1673   if (type == TS_LINEAR) {
1674     SNES snes;
1675     ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1676     ierr = SNESSetType(snes,SNESKSPONLY);CHKERRQ(ierr);
1677   }
1678   PetscFunctionReturn(0);
1679 }
1680 
1681 #undef __FUNCT__
1682 #define __FUNCT__ "TSGetProblemType"
1683 /*@C
1684   TSGetProblemType - Gets the type of problem to be solved.
1685 
1686   Not collective
1687 
1688   Input Parameter:
1689 . ts   - The TS
1690 
1691   Output Parameter:
1692 . type - One of TS_LINEAR, TS_NONLINEAR where these types refer to problems of the forms
1693 .vb
1694          M U_t = A U
1695          M(t) U_t = A(t) U
1696          F(t,U,U_t)
1697 .ve
1698 
1699    Level: beginner
1700 
1701 .keywords: TS, problem type
1702 .seealso: TSSetUp(), TSProblemType, TS
1703 @*/
1704 PetscErrorCode  TSGetProblemType(TS ts, TSProblemType *type)
1705 {
1706   PetscFunctionBegin;
1707   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
1708   PetscValidIntPointer(type,2);
1709   *type = ts->problem_type;
1710   PetscFunctionReturn(0);
1711 }
1712 
1713 #undef __FUNCT__
1714 #define __FUNCT__ "TSSetUp"
1715 /*@
1716    TSSetUp - Sets up the internal data structures for the later use
1717    of a timestepper.
1718 
1719    Collective on TS
1720 
1721    Input Parameter:
1722 .  ts - the TS context obtained from TSCreate()
1723 
1724    Notes:
1725    For basic use of the TS solvers the user need not explicitly call
1726    TSSetUp(), since these actions will automatically occur during
1727    the call to TSStep().  However, if one wishes to control this
1728    phase separately, TSSetUp() should be called after TSCreate()
1729    and optional routines of the form TSSetXXX(), but before TSStep().
1730 
1731    Level: advanced
1732 
1733 .keywords: TS, timestep, setup
1734 
1735 .seealso: TSCreate(), TSStep(), TSDestroy()
1736 @*/
1737 PetscErrorCode  TSSetUp(TS ts)
1738 {
1739   PetscErrorCode ierr;
1740   DM             dm;
1741   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
1742   PetscErrorCode (*jac)(SNES,Vec,Mat*,Mat*,MatStructure*,void*);
1743   TSIJacobian    ijac;
1744   TSRHSJacobian  rhsjac;
1745 
1746   PetscFunctionBegin;
1747   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1748   if (ts->setupcalled) PetscFunctionReturn(0);
1749 
1750   if (!((PetscObject)ts)->type_name) {
1751     ierr = TSSetType(ts,TSEULER);CHKERRQ(ierr);
1752   }
1753 
1754   if (!ts->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Must call TSSetSolution() first");
1755 
1756   ierr = TSGetAdapt(ts,&ts->adapt);CHKERRQ(ierr);
1757 
1758   if (ts->rhsjacobian.reuse) {
1759     Mat Amat,Pmat;
1760     SNES snes;
1761     ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1762     ierr = SNESGetJacobian(snes,&Amat,&Pmat,NULL,NULL);CHKERRQ(ierr);
1763     /* Matching matrices implies that an IJacobian is NOT set, because if it had been set, the IJacobian's matrix would
1764      * have displaced the RHS matrix */
1765     if (Amat == ts->Arhs) {
1766       ierr = MatDuplicate(ts->Arhs,MAT_DO_NOT_COPY_VALUES,&Amat);CHKERRQ(ierr);
1767       ierr = SNESSetJacobian(snes,Amat,NULL,NULL,NULL);CHKERRQ(ierr);
1768       ierr = MatDestroy(&Amat);CHKERRQ(ierr);
1769     }
1770     if (Pmat == ts->Brhs) {
1771       ierr = MatDuplicate(ts->Brhs,MAT_DO_NOT_COPY_VALUES,&Pmat);CHKERRQ(ierr);
1772       ierr = SNESSetJacobian(snes,NULL,Pmat,NULL,NULL);CHKERRQ(ierr);
1773       ierr = MatDestroy(&Pmat);CHKERRQ(ierr);
1774     }
1775   }
1776 
1777   if (ts->ops->setup) {
1778     ierr = (*ts->ops->setup)(ts);CHKERRQ(ierr);
1779   }
1780 
1781   /* in the case where we've set a DMTSFunction or what have you, we need the default SNESFunction
1782    to be set right but can't do it elsewhere due to the overreliance on ctx=ts.
1783    */
1784   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1785   ierr = DMSNESGetFunction(dm,&func,NULL);CHKERRQ(ierr);
1786   if (!func) {
1787     ierr =DMSNESSetFunction(dm,SNESTSFormFunction,ts);CHKERRQ(ierr);
1788   }
1789   /* if the SNES doesn't have a jacobian set and the TS has an ijacobian or rhsjacobian set, set the SNES to use it.
1790      Otherwise, the SNES will use coloring internally to form the Jacobian.
1791    */
1792   ierr = DMSNESGetJacobian(dm,&jac,NULL);CHKERRQ(ierr);
1793   ierr = DMTSGetIJacobian(dm,&ijac,NULL);CHKERRQ(ierr);
1794   ierr = DMTSGetRHSJacobian(dm,&rhsjac,NULL);CHKERRQ(ierr);
1795   if (!jac && (ijac || rhsjac)) {
1796     ierr = DMSNESSetJacobian(dm,SNESTSFormJacobian,ts);CHKERRQ(ierr);
1797   }
1798   ts->setupcalled = PETSC_TRUE;
1799   PetscFunctionReturn(0);
1800 }
1801 
1802 #undef __FUNCT__
1803 #define __FUNCT__ "TSReset"
1804 /*@
1805    TSReset - Resets a TS context and removes any allocated Vecs and Mats.
1806 
1807    Collective on TS
1808 
1809    Input Parameter:
1810 .  ts - the TS context obtained from TSCreate()
1811 
1812    Level: beginner
1813 
1814 .keywords: TS, timestep, reset
1815 
1816 .seealso: TSCreate(), TSSetup(), TSDestroy()
1817 @*/
1818 PetscErrorCode  TSReset(TS ts)
1819 {
1820   PetscErrorCode ierr;
1821 
1822   PetscFunctionBegin;
1823   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1824   if (ts->ops->reset) {
1825     ierr = (*ts->ops->reset)(ts);CHKERRQ(ierr);
1826   }
1827   if (ts->snes) {ierr = SNESReset(ts->snes);CHKERRQ(ierr);}
1828 
1829   ierr = MatDestroy(&ts->Arhs);CHKERRQ(ierr);
1830   ierr = MatDestroy(&ts->Brhs);CHKERRQ(ierr);
1831   ierr = VecDestroy(&ts->Frhs);CHKERRQ(ierr);
1832   ierr = VecDestroy(&ts->vec_sol);CHKERRQ(ierr);
1833   ierr = VecDestroy(&ts->vatol);CHKERRQ(ierr);
1834   ierr = VecDestroy(&ts->vrtol);CHKERRQ(ierr);
1835   ierr = VecDestroyVecs(ts->nwork,&ts->work);CHKERRQ(ierr);
1836 
1837   ts->setupcalled = PETSC_FALSE;
1838   PetscFunctionReturn(0);
1839 }
1840 
1841 #undef __FUNCT__
1842 #define __FUNCT__ "TSDestroy"
1843 /*@
1844    TSDestroy - Destroys the timestepper context that was created
1845    with TSCreate().
1846 
1847    Collective on TS
1848 
1849    Input Parameter:
1850 .  ts - the TS context obtained from TSCreate()
1851 
1852    Level: beginner
1853 
1854 .keywords: TS, timestepper, destroy
1855 
1856 .seealso: TSCreate(), TSSetUp(), TSSolve()
1857 @*/
1858 PetscErrorCode  TSDestroy(TS *ts)
1859 {
1860   PetscErrorCode ierr;
1861 
1862   PetscFunctionBegin;
1863   if (!*ts) PetscFunctionReturn(0);
1864   PetscValidHeaderSpecific((*ts),TS_CLASSID,1);
1865   if (--((PetscObject)(*ts))->refct > 0) {*ts = 0; PetscFunctionReturn(0);}
1866 
1867   ierr = TSReset((*ts));CHKERRQ(ierr);
1868 
1869   /* if memory was published with SAWs then destroy it */
1870   ierr = PetscObjectSAWsViewOff((PetscObject)*ts);CHKERRQ(ierr);
1871   if ((*ts)->ops->destroy) {ierr = (*(*ts)->ops->destroy)((*ts));CHKERRQ(ierr);}
1872 
1873   ierr = TSAdaptDestroy(&(*ts)->adapt);CHKERRQ(ierr);
1874   ierr = SNESDestroy(&(*ts)->snes);CHKERRQ(ierr);
1875   ierr = DMDestroy(&(*ts)->dm);CHKERRQ(ierr);
1876   ierr = TSMonitorCancel((*ts));CHKERRQ(ierr);
1877 
1878   ierr = PetscHeaderDestroy(ts);CHKERRQ(ierr);
1879   PetscFunctionReturn(0);
1880 }
1881 
1882 #undef __FUNCT__
1883 #define __FUNCT__ "TSGetSNES"
1884 /*@
1885    TSGetSNES - Returns the SNES (nonlinear solver) associated with
1886    a TS (timestepper) context. Valid only for nonlinear problems.
1887 
1888    Not Collective, but SNES is parallel if TS is parallel
1889 
1890    Input Parameter:
1891 .  ts - the TS context obtained from TSCreate()
1892 
1893    Output Parameter:
1894 .  snes - the nonlinear solver context
1895 
1896    Notes:
1897    The user can then directly manipulate the SNES context to set various
1898    options, etc.  Likewise, the user can then extract and manipulate the
1899    KSP, KSP, and PC contexts as well.
1900 
1901    TSGetSNES() does not work for integrators that do not use SNES; in
1902    this case TSGetSNES() returns NULL in snes.
1903 
1904    Level: beginner
1905 
1906 .keywords: timestep, get, SNES
1907 @*/
1908 PetscErrorCode  TSGetSNES(TS ts,SNES *snes)
1909 {
1910   PetscErrorCode ierr;
1911 
1912   PetscFunctionBegin;
1913   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1914   PetscValidPointer(snes,2);
1915   if (!ts->snes) {
1916     ierr = SNESCreate(PetscObjectComm((PetscObject)ts),&ts->snes);CHKERRQ(ierr);
1917     ierr = SNESSetFunction(ts->snes,NULL,SNESTSFormFunction,ts);CHKERRQ(ierr);
1918     ierr = PetscLogObjectParent(ts,ts->snes);CHKERRQ(ierr);
1919     ierr = PetscObjectIncrementTabLevel((PetscObject)ts->snes,(PetscObject)ts,1);CHKERRQ(ierr);
1920     if (ts->dm) {ierr = SNESSetDM(ts->snes,ts->dm);CHKERRQ(ierr);}
1921     if (ts->problem_type == TS_LINEAR) {
1922       ierr = SNESSetType(ts->snes,SNESKSPONLY);CHKERRQ(ierr);
1923     }
1924   }
1925   *snes = ts->snes;
1926   PetscFunctionReturn(0);
1927 }
1928 
1929 #undef __FUNCT__
1930 #define __FUNCT__ "TSSetSNES"
1931 /*@
1932    TSSetSNES - Set the SNES (nonlinear solver) to be used by the timestepping context
1933 
1934    Collective
1935 
1936    Input Parameter:
1937 +  ts - the TS context obtained from TSCreate()
1938 -  snes - the nonlinear solver context
1939 
1940    Notes:
1941    Most users should have the TS created by calling TSGetSNES()
1942 
1943    Level: developer
1944 
1945 .keywords: timestep, set, SNES
1946 @*/
1947 PetscErrorCode TSSetSNES(TS ts,SNES snes)
1948 {
1949   PetscErrorCode ierr;
1950   PetscErrorCode (*func)(SNES,Vec,Mat*,Mat*,MatStructure*,void*);
1951 
1952   PetscFunctionBegin;
1953   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1954   PetscValidHeaderSpecific(snes,SNES_CLASSID,2);
1955   ierr = PetscObjectReference((PetscObject)snes);CHKERRQ(ierr);
1956   ierr = SNESDestroy(&ts->snes);CHKERRQ(ierr);
1957 
1958   ts->snes = snes;
1959 
1960   ierr = SNESSetFunction(ts->snes,NULL,SNESTSFormFunction,ts);CHKERRQ(ierr);
1961   ierr = SNESGetJacobian(ts->snes,NULL,NULL,&func,NULL);CHKERRQ(ierr);
1962   if (func == SNESTSFormJacobian) {
1963     ierr = SNESSetJacobian(ts->snes,NULL,NULL,SNESTSFormJacobian,ts);CHKERRQ(ierr);
1964   }
1965   PetscFunctionReturn(0);
1966 }
1967 
1968 #undef __FUNCT__
1969 #define __FUNCT__ "TSGetKSP"
1970 /*@
1971    TSGetKSP - Returns the KSP (linear solver) associated with
1972    a TS (timestepper) context.
1973 
1974    Not Collective, but KSP is parallel if TS is parallel
1975 
1976    Input Parameter:
1977 .  ts - the TS context obtained from TSCreate()
1978 
1979    Output Parameter:
1980 .  ksp - the nonlinear solver context
1981 
1982    Notes:
1983    The user can then directly manipulate the KSP context to set various
1984    options, etc.  Likewise, the user can then extract and manipulate the
1985    KSP and PC contexts as well.
1986 
1987    TSGetKSP() does not work for integrators that do not use KSP;
1988    in this case TSGetKSP() returns NULL in ksp.
1989 
1990    Level: beginner
1991 
1992 .keywords: timestep, get, KSP
1993 @*/
1994 PetscErrorCode  TSGetKSP(TS ts,KSP *ksp)
1995 {
1996   PetscErrorCode ierr;
1997   SNES           snes;
1998 
1999   PetscFunctionBegin;
2000   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2001   PetscValidPointer(ksp,2);
2002   if (!((PetscObject)ts)->type_name) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"KSP is not created yet. Call TSSetType() first");
2003   if (ts->problem_type != TS_LINEAR) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Linear only; use TSGetSNES()");
2004   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2005   ierr = SNESGetKSP(snes,ksp);CHKERRQ(ierr);
2006   PetscFunctionReturn(0);
2007 }
2008 
2009 /* ----------- Routines to set solver parameters ---------- */
2010 
2011 #undef __FUNCT__
2012 #define __FUNCT__ "TSGetDuration"
2013 /*@
2014    TSGetDuration - Gets the maximum number of timesteps to use and
2015    maximum time for iteration.
2016 
2017    Not Collective
2018 
2019    Input Parameters:
2020 +  ts       - the TS context obtained from TSCreate()
2021 .  maxsteps - maximum number of iterations to use, or NULL
2022 -  maxtime  - final time to iterate to, or NULL
2023 
2024    Level: intermediate
2025 
2026 .keywords: TS, timestep, get, maximum, iterations, time
2027 @*/
2028 PetscErrorCode  TSGetDuration(TS ts, PetscInt *maxsteps, PetscReal *maxtime)
2029 {
2030   PetscFunctionBegin;
2031   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2032   if (maxsteps) {
2033     PetscValidIntPointer(maxsteps,2);
2034     *maxsteps = ts->max_steps;
2035   }
2036   if (maxtime) {
2037     PetscValidScalarPointer(maxtime,3);
2038     *maxtime = ts->max_time;
2039   }
2040   PetscFunctionReturn(0);
2041 }
2042 
2043 #undef __FUNCT__
2044 #define __FUNCT__ "TSSetDuration"
2045 /*@
2046    TSSetDuration - Sets the maximum number of timesteps to use and
2047    maximum time for iteration.
2048 
2049    Logically Collective on TS
2050 
2051    Input Parameters:
2052 +  ts - the TS context obtained from TSCreate()
2053 .  maxsteps - maximum number of iterations to use
2054 -  maxtime - final time to iterate to
2055 
2056    Options Database Keys:
2057 .  -ts_max_steps <maxsteps> - Sets maxsteps
2058 .  -ts_final_time <maxtime> - Sets maxtime
2059 
2060    Notes:
2061    The default maximum number of iterations is 5000. Default time is 5.0
2062 
2063    Level: intermediate
2064 
2065 .keywords: TS, timestep, set, maximum, iterations
2066 
2067 .seealso: TSSetExactFinalTime()
2068 @*/
2069 PetscErrorCode  TSSetDuration(TS ts,PetscInt maxsteps,PetscReal maxtime)
2070 {
2071   PetscFunctionBegin;
2072   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2073   PetscValidLogicalCollectiveInt(ts,maxsteps,2);
2074   PetscValidLogicalCollectiveReal(ts,maxtime,2);
2075   if (maxsteps >= 0) ts->max_steps = maxsteps;
2076   if (maxtime != PETSC_DEFAULT) ts->max_time = maxtime;
2077   PetscFunctionReturn(0);
2078 }
2079 
2080 #undef __FUNCT__
2081 #define __FUNCT__ "TSSetSolution"
2082 /*@
2083    TSSetSolution - Sets the initial solution vector
2084    for use by the TS routines.
2085 
2086    Logically Collective on TS and Vec
2087 
2088    Input Parameters:
2089 +  ts - the TS context obtained from TSCreate()
2090 -  u - the solution vector
2091 
2092    Level: beginner
2093 
2094 .keywords: TS, timestep, set, solution, initial conditions
2095 @*/
2096 PetscErrorCode  TSSetSolution(TS ts,Vec u)
2097 {
2098   PetscErrorCode ierr;
2099   DM             dm;
2100 
2101   PetscFunctionBegin;
2102   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2103   PetscValidHeaderSpecific(u,VEC_CLASSID,2);
2104   ierr = PetscObjectReference((PetscObject)u);CHKERRQ(ierr);
2105   ierr = VecDestroy(&ts->vec_sol);CHKERRQ(ierr);
2106 
2107   ts->vec_sol = u;
2108 
2109   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
2110   ierr = DMShellSetGlobalVector(dm,u);CHKERRQ(ierr);
2111   PetscFunctionReturn(0);
2112 }
2113 
2114 #undef __FUNCT__
2115 #define __FUNCT__ "TSSetPreStep"
2116 /*@C
2117   TSSetPreStep - Sets the general-purpose function
2118   called once at the beginning of each time step.
2119 
2120   Logically Collective on TS
2121 
2122   Input Parameters:
2123 + ts   - The TS context obtained from TSCreate()
2124 - func - The function
2125 
2126   Calling sequence of func:
2127 . func (TS ts);
2128 
2129   Level: intermediate
2130 
2131   Note:
2132   If a step is rejected, TSStep() will call this routine again before each attempt.
2133   The last completed time step number can be queried using TSGetTimeStepNumber(), the
2134   size of the step being attempted can be obtained using TSGetTimeStep().
2135 
2136 .keywords: TS, timestep
2137 .seealso: TSSetPreStage(), TSSetPostStep(), TSStep()
2138 @*/
2139 PetscErrorCode  TSSetPreStep(TS ts, PetscErrorCode (*func)(TS))
2140 {
2141   PetscFunctionBegin;
2142   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2143   ts->prestep = func;
2144   PetscFunctionReturn(0);
2145 }
2146 
2147 #undef __FUNCT__
2148 #define __FUNCT__ "TSPreStep"
2149 /*@
2150   TSPreStep - Runs the user-defined pre-step function.
2151 
2152   Collective on TS
2153 
2154   Input Parameters:
2155 . ts   - The TS context obtained from TSCreate()
2156 
2157   Notes:
2158   TSPreStep() is typically used within time stepping implementations,
2159   so most users would not generally call this routine themselves.
2160 
2161   Level: developer
2162 
2163 .keywords: TS, timestep
2164 .seealso: TSSetPreStep(), TSPreStage(), TSPostStep()
2165 @*/
2166 PetscErrorCode  TSPreStep(TS ts)
2167 {
2168   PetscErrorCode ierr;
2169 
2170   PetscFunctionBegin;
2171   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2172   if (ts->prestep) {
2173     PetscStackCallStandard((*ts->prestep),(ts));
2174   }
2175   PetscFunctionReturn(0);
2176 }
2177 
2178 #undef __FUNCT__
2179 #define __FUNCT__ "TSSetPreStage"
2180 /*@C
2181   TSSetPreStage - Sets the general-purpose function
2182   called once at the beginning of each stage.
2183 
2184   Logically Collective on TS
2185 
2186   Input Parameters:
2187 + ts   - The TS context obtained from TSCreate()
2188 - func - The function
2189 
2190   Calling sequence of func:
2191 . PetscErrorCode func(TS ts, PetscReal stagetime);
2192 
2193   Level: intermediate
2194 
2195   Note:
2196   There may be several stages per time step. If the solve for a given stage fails, the step may be rejected and retried.
2197   The time step number being computed can be queried using TSGetTimeStepNumber() and the total size of the step being
2198   attempted can be obtained using TSGetTimeStep(). The time at the start of the step is available via TSGetTime().
2199 
2200 .keywords: TS, timestep
2201 .seealso: TSSetPreStep(), TSSetPostStep(), TSGetApplicationContext()
2202 @*/
2203 PetscErrorCode  TSSetPreStage(TS ts, PetscErrorCode (*func)(TS,PetscReal))
2204 {
2205   PetscFunctionBegin;
2206   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2207   ts->prestage = func;
2208   PetscFunctionReturn(0);
2209 }
2210 
2211 #undef __FUNCT__
2212 #define __FUNCT__ "TSPreStage"
2213 /*@
2214   TSPreStage - Runs the user-defined pre-stage function set using TSSetPreStage()
2215 
2216   Collective on TS
2217 
2218   Input Parameters:
2219 . ts   - The TS context obtained from TSCreate()
2220 
2221   Notes:
2222   TSPreStage() is typically used within time stepping implementations,
2223   most users would not generally call this routine themselves.
2224 
2225   Level: developer
2226 
2227 .keywords: TS, timestep
2228 .seealso: TSSetPreStep(), TSPreStep(), TSPostStep()
2229 @*/
2230 PetscErrorCode  TSPreStage(TS ts, PetscReal stagetime)
2231 {
2232   PetscErrorCode ierr;
2233 
2234   PetscFunctionBegin;
2235   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2236   if (ts->prestage) {
2237     PetscStackCallStandard((*ts->prestage),(ts,stagetime));
2238   }
2239   PetscFunctionReturn(0);
2240 }
2241 
2242 #undef __FUNCT__
2243 #define __FUNCT__ "TSSetPostStep"
2244 /*@C
2245   TSSetPostStep - Sets the general-purpose function
2246   called once at the end of each time step.
2247 
2248   Logically Collective on TS
2249 
2250   Input Parameters:
2251 + ts   - The TS context obtained from TSCreate()
2252 - func - The function
2253 
2254   Calling sequence of func:
2255 $ func (TS ts);
2256 
2257   Level: intermediate
2258 
2259 .keywords: TS, timestep
2260 .seealso: TSSetPreStep(), TSSetPreStage(), TSGetTimeStep(), TSGetTimeStepNumber(), TSGetTime()
2261 @*/
2262 PetscErrorCode  TSSetPostStep(TS ts, PetscErrorCode (*func)(TS))
2263 {
2264   PetscFunctionBegin;
2265   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2266   ts->poststep = func;
2267   PetscFunctionReturn(0);
2268 }
2269 
2270 #undef __FUNCT__
2271 #define __FUNCT__ "TSPostStep"
2272 /*@
2273   TSPostStep - Runs the user-defined post-step function.
2274 
2275   Collective on TS
2276 
2277   Input Parameters:
2278 . ts   - The TS context obtained from TSCreate()
2279 
2280   Notes:
2281   TSPostStep() is typically used within time stepping implementations,
2282   so most users would not generally call this routine themselves.
2283 
2284   Level: developer
2285 
2286 .keywords: TS, timestep
2287 @*/
2288 PetscErrorCode  TSPostStep(TS ts)
2289 {
2290   PetscErrorCode ierr;
2291 
2292   PetscFunctionBegin;
2293   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2294   if (ts->poststep) {
2295     PetscStackCallStandard((*ts->poststep),(ts));
2296   }
2297   PetscFunctionReturn(0);
2298 }
2299 
2300 /* ------------ Routines to set performance monitoring options ----------- */
2301 
2302 #undef __FUNCT__
2303 #define __FUNCT__ "TSMonitorSet"
2304 /*@C
2305    TSMonitorSet - Sets an ADDITIONAL function that is to be used at every
2306    timestep to display the iteration's  progress.
2307 
2308    Logically Collective on TS
2309 
2310    Input Parameters:
2311 +  ts - the TS context obtained from TSCreate()
2312 .  monitor - monitoring routine
2313 .  mctx - [optional] user-defined context for private data for the
2314              monitor routine (use NULL if no context is desired)
2315 -  monitordestroy - [optional] routine that frees monitor context
2316           (may be NULL)
2317 
2318    Calling sequence of monitor:
2319 $    int monitor(TS ts,PetscInt steps,PetscReal time,Vec u,void *mctx)
2320 
2321 +    ts - the TS context
2322 .    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
2323                                been interpolated to)
2324 .    time - current time
2325 .    u - current iterate
2326 -    mctx - [optional] monitoring context
2327 
2328    Notes:
2329    This routine adds an additional monitor to the list of monitors that
2330    already has been loaded.
2331 
2332    Fortran notes: Only a single monitor function can be set for each TS object
2333 
2334    Level: intermediate
2335 
2336 .keywords: TS, timestep, set, monitor
2337 
2338 .seealso: TSMonitorDefault(), TSMonitorCancel()
2339 @*/
2340 PetscErrorCode  TSMonitorSet(TS ts,PetscErrorCode (*monitor)(TS,PetscInt,PetscReal,Vec,void*),void *mctx,PetscErrorCode (*mdestroy)(void**))
2341 {
2342   PetscFunctionBegin;
2343   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2344   if (ts->numbermonitors >= MAXTSMONITORS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
2345   ts->monitor[ts->numbermonitors]          = monitor;
2346   ts->monitordestroy[ts->numbermonitors]   = mdestroy;
2347   ts->monitorcontext[ts->numbermonitors++] = (void*)mctx;
2348   PetscFunctionReturn(0);
2349 }
2350 
2351 #undef __FUNCT__
2352 #define __FUNCT__ "TSMonitorCancel"
2353 /*@C
2354    TSMonitorCancel - Clears all the monitors that have been set on a time-step object.
2355 
2356    Logically Collective on TS
2357 
2358    Input Parameters:
2359 .  ts - the TS context obtained from TSCreate()
2360 
2361    Notes:
2362    There is no way to remove a single, specific monitor.
2363 
2364    Level: intermediate
2365 
2366 .keywords: TS, timestep, set, monitor
2367 
2368 .seealso: TSMonitorDefault(), TSMonitorSet()
2369 @*/
2370 PetscErrorCode  TSMonitorCancel(TS ts)
2371 {
2372   PetscErrorCode ierr;
2373   PetscInt       i;
2374 
2375   PetscFunctionBegin;
2376   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2377   for (i=0; i<ts->numbermonitors; i++) {
2378     if (ts->monitordestroy[i]) {
2379       ierr = (*ts->monitordestroy[i])(&ts->monitorcontext[i]);CHKERRQ(ierr);
2380     }
2381   }
2382   ts->numbermonitors = 0;
2383   PetscFunctionReturn(0);
2384 }
2385 
2386 #undef __FUNCT__
2387 #define __FUNCT__ "TSMonitorDefault"
2388 /*@
2389    TSMonitorDefault - Sets the Default monitor
2390 
2391    Level: intermediate
2392 
2393 .keywords: TS, set, monitor
2394 
2395 .seealso: TSMonitorDefault(), TSMonitorSet()
2396 @*/
2397 PetscErrorCode TSMonitorDefault(TS ts,PetscInt step,PetscReal ptime,Vec v,void *dummy)
2398 {
2399   PetscErrorCode ierr;
2400   PetscViewer    viewer = dummy ? (PetscViewer) dummy : PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)ts));
2401 
2402   PetscFunctionBegin;
2403   ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)ts)->tablevel);CHKERRQ(ierr);
2404   ierr = PetscViewerASCIIPrintf(viewer,"%D TS dt %g time %g\n",step,(double)ts->time_step,(double)ptime);CHKERRQ(ierr);
2405   ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)ts)->tablevel);CHKERRQ(ierr);
2406   PetscFunctionReturn(0);
2407 }
2408 
2409 #undef __FUNCT__
2410 #define __FUNCT__ "TSSetRetainStages"
2411 /*@
2412    TSSetRetainStages - Request that all stages in the upcoming step be stored so that interpolation will be available.
2413 
2414    Logically Collective on TS
2415 
2416    Input Argument:
2417 .  ts - time stepping context
2418 
2419    Output Argument:
2420 .  flg - PETSC_TRUE or PETSC_FALSE
2421 
2422    Level: intermediate
2423 
2424 .keywords: TS, set
2425 
2426 .seealso: TSInterpolate(), TSSetPostStep()
2427 @*/
2428 PetscErrorCode TSSetRetainStages(TS ts,PetscBool flg)
2429 {
2430   PetscFunctionBegin;
2431   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2432   ts->retain_stages = flg;
2433   PetscFunctionReturn(0);
2434 }
2435 
2436 #undef __FUNCT__
2437 #define __FUNCT__ "TSInterpolate"
2438 /*@
2439    TSInterpolate - Interpolate the solution computed during the previous step to an arbitrary location in the interval
2440 
2441    Collective on TS
2442 
2443    Input Argument:
2444 +  ts - time stepping context
2445 -  t - time to interpolate to
2446 
2447    Output Argument:
2448 .  U - state at given time
2449 
2450    Notes:
2451    The user should call TSSetRetainStages() before taking a step in which interpolation will be requested.
2452 
2453    Level: intermediate
2454 
2455    Developer Notes:
2456    TSInterpolate() and the storing of previous steps/stages should be generalized to support delay differential equations and continuous adjoints.
2457 
2458 .keywords: TS, set
2459 
2460 .seealso: TSSetRetainStages(), TSSetPostStep()
2461 @*/
2462 PetscErrorCode TSInterpolate(TS ts,PetscReal t,Vec U)
2463 {
2464   PetscErrorCode ierr;
2465 
2466   PetscFunctionBegin;
2467   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2468   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
2469   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);
2470   if (!ts->ops->interpolate) SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"%s does not provide interpolation",((PetscObject)ts)->type_name);
2471   ierr = (*ts->ops->interpolate)(ts,t,U);CHKERRQ(ierr);
2472   PetscFunctionReturn(0);
2473 }
2474 
2475 #undef __FUNCT__
2476 #define __FUNCT__ "TSStep"
2477 /*@
2478    TSStep - Steps one time step
2479 
2480    Collective on TS
2481 
2482    Input Parameter:
2483 .  ts - the TS context obtained from TSCreate()
2484 
2485    Level: intermediate
2486 
2487    Notes:
2488    The hook set using TSSetPreStep() is called before each attempt to take the step. In general, the time step size may
2489    be changed due to adaptive error controller or solve failures. Note that steps may contain multiple stages.
2490 
2491    This may over-step the final time provided in TSSetDuration() depending on the time-step used. TSSolve() interpolates to exactly the
2492    time provided in TSSetDuration(). One can use TSInterpolate() to determine an interpolated solution within the final timestep.
2493 
2494 .keywords: TS, timestep, solve
2495 
2496 .seealso: TSCreate(), TSSetUp(), TSDestroy(), TSSolve(), TSSetPreStep(), TSSetPreStage(), TSInterpolate()
2497 @*/
2498 PetscErrorCode  TSStep(TS ts)
2499 {
2500   PetscReal      ptime_prev;
2501   PetscErrorCode ierr;
2502 
2503   PetscFunctionBegin;
2504   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2505   ierr = TSSetUp(ts);CHKERRQ(ierr);
2506 
2507   ts->reason = TS_CONVERGED_ITERATING;
2508   ptime_prev = ts->ptime;
2509 
2510   ierr = PetscLogEventBegin(TS_Step,ts,0,0,0);CHKERRQ(ierr);
2511   ierr = (*ts->ops->step)(ts);CHKERRQ(ierr);
2512   ierr = PetscLogEventEnd(TS_Step,ts,0,0,0);CHKERRQ(ierr);
2513 
2514   ts->time_step_prev = ts->ptime - ptime_prev;
2515 
2516   if (ts->reason < 0) {
2517     if (ts->errorifstepfailed) {
2518       if (ts->reason == TS_DIVERGED_NONLINEAR_SOLVE) {
2519         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]);
2520       } else SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_NOT_CONVERGED,"TSStep has failed due to %s",TSConvergedReasons[ts->reason]);
2521     }
2522   } else if (!ts->reason) {
2523     if (ts->steps >= ts->max_steps)     ts->reason = TS_CONVERGED_ITS;
2524     else if (ts->ptime >= ts->max_time) ts->reason = TS_CONVERGED_TIME;
2525   }
2526   PetscFunctionReturn(0);
2527 }
2528 
2529 #undef __FUNCT__
2530 #define __FUNCT__ "TSEvaluateStep"
2531 /*@
2532    TSEvaluateStep - Evaluate the solution at the end of a time step with a given order of accuracy.
2533 
2534    Collective on TS
2535 
2536    Input Arguments:
2537 +  ts - time stepping context
2538 .  order - desired order of accuracy
2539 -  done - whether the step was evaluated at this order (pass NULL to generate an error if not available)
2540 
2541    Output Arguments:
2542 .  U - state at the end of the current step
2543 
2544    Level: advanced
2545 
2546    Notes:
2547    This function cannot be called until all stages have been evaluated.
2548    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.
2549 
2550 .seealso: TSStep(), TSAdapt
2551 @*/
2552 PetscErrorCode TSEvaluateStep(TS ts,PetscInt order,Vec U,PetscBool *done)
2553 {
2554   PetscErrorCode ierr;
2555 
2556   PetscFunctionBegin;
2557   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2558   PetscValidType(ts,1);
2559   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
2560   if (!ts->ops->evaluatestep) SETERRQ1(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"TSEvaluateStep not implemented for type '%s'",((PetscObject)ts)->type_name);
2561   ierr = (*ts->ops->evaluatestep)(ts,order,U,done);CHKERRQ(ierr);
2562   PetscFunctionReturn(0);
2563 }
2564 
2565 #undef __FUNCT__
2566 #define __FUNCT__ "TSSolve"
2567 /*@
2568    TSSolve - Steps the requested number of timesteps.
2569 
2570    Collective on TS
2571 
2572    Input Parameter:
2573 +  ts - the TS context obtained from TSCreate()
2574 -  u - the solution vector  (can be null if TSSetSolution() was used, otherwise must contain the initial conditions)
2575 
2576    Level: beginner
2577 
2578    Notes:
2579    The final time returned by this function may be different from the time of the internally
2580    held state accessible by TSGetSolution() and TSGetTime() because the method may have
2581    stepped over the final time.
2582 
2583 .keywords: TS, timestep, solve
2584 
2585 .seealso: TSCreate(), TSSetSolution(), TSStep()
2586 @*/
2587 PetscErrorCode TSSolve(TS ts,Vec u)
2588 {
2589   PetscBool         flg;
2590   PetscViewer       viewer;
2591   Vec               solution;
2592   PetscErrorCode    ierr;
2593   PetscViewerFormat format;
2594 
2595   PetscFunctionBegin;
2596   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2597   if (u) PetscValidHeaderSpecific(u,VEC_CLASSID,2);
2598   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 */
2599     PetscValidHeaderSpecific(u,VEC_CLASSID,2);
2600     if (!ts->vec_sol || u == ts->vec_sol) {
2601       ierr = VecDuplicate(u,&solution);CHKERRQ(ierr);
2602       ierr = TSSetSolution(ts,solution);CHKERRQ(ierr);
2603       ierr = VecDestroy(&solution);CHKERRQ(ierr); /* grant ownership */
2604     }
2605     ierr = VecCopy(u,ts->vec_sol);CHKERRQ(ierr);
2606   } else if (u) {
2607     ierr = TSSetSolution(ts,u);CHKERRQ(ierr);
2608   }
2609   ierr = TSSetUp(ts);CHKERRQ(ierr);
2610   /* reset time step and iteration counters */
2611   ts->steps             = 0;
2612   ts->ksp_its           = 0;
2613   ts->snes_its          = 0;
2614   ts->num_snes_failures = 0;
2615   ts->reject            = 0;
2616   ts->reason            = TS_CONVERGED_ITERATING;
2617 
2618   ierr = PetscOptionsGetViewer(PetscObjectComm((PetscObject)ts),((PetscObject)ts)->prefix,"-ts_view_pre",&viewer,&format,&flg);CHKERRQ(ierr);
2619   if (flg && !PetscPreLoadingOn) {
2620     ierr = PetscViewerPushFormat(viewer,format);CHKERRQ(ierr);
2621     ierr = TSView(ts,viewer);CHKERRQ(ierr);
2622     ierr = PetscViewerPopFormat(viewer);CHKERRQ(ierr);
2623     ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
2624   }
2625 
2626   if (ts->ops->solve) {         /* This private interface is transitional and should be removed when all implementations are updated. */
2627     ierr = (*ts->ops->solve)(ts);CHKERRQ(ierr);
2628     ierr = VecCopy(ts->vec_sol,u);CHKERRQ(ierr);
2629     ts->solvetime = ts->ptime;
2630   } else {
2631     /* steps the requested number of timesteps. */
2632     if (ts->steps >= ts->max_steps)     ts->reason = TS_CONVERGED_ITS;
2633     else if (ts->ptime >= ts->max_time) ts->reason = TS_CONVERGED_TIME;
2634     while (!ts->reason) {
2635       ierr = TSMonitor(ts,ts->steps,ts->ptime,ts->vec_sol);CHKERRQ(ierr);
2636       ierr = TSStep(ts);CHKERRQ(ierr);
2637       ierr = TSPostStep(ts);CHKERRQ(ierr);
2638     }
2639     if (ts->exact_final_time == TS_EXACTFINALTIME_INTERPOLATE && ts->ptime > ts->max_time) {
2640       ierr = TSInterpolate(ts,ts->max_time,u);CHKERRQ(ierr);
2641       ts->solvetime = ts->max_time;
2642       solution = u;
2643     } else {
2644       if (u) {ierr = VecCopy(ts->vec_sol,u);CHKERRQ(ierr);}
2645       ts->solvetime = ts->ptime;
2646       solution = ts->vec_sol;
2647     }
2648     ierr = TSMonitor(ts,ts->steps,ts->solvetime,solution);CHKERRQ(ierr);
2649   }
2650   ierr = PetscOptionsGetViewer(PetscObjectComm((PetscObject)ts),((PetscObject)ts)->prefix,"-ts_view",&viewer,&format,&flg);CHKERRQ(ierr);
2651   if (flg && !PetscPreLoadingOn) {
2652     ierr = PetscViewerPushFormat(viewer,format);CHKERRQ(ierr);
2653     ierr = TSView(ts,viewer);CHKERRQ(ierr);
2654     ierr = PetscViewerPopFormat(viewer);CHKERRQ(ierr);
2655     ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
2656   }
2657   PetscFunctionReturn(0);
2658 }
2659 
2660 #undef __FUNCT__
2661 #define __FUNCT__ "TSMonitor"
2662 /*@
2663    TSMonitor - Runs all user-provided monitor routines set using TSMonitorSet()
2664 
2665    Collective on TS
2666 
2667    Input Parameters:
2668 +  ts - time stepping context obtained from TSCreate()
2669 .  step - step number that has just completed
2670 .  ptime - model time of the state
2671 -  u - state at the current model time
2672 
2673    Notes:
2674    TSMonitor() is typically used within the time stepping implementations.
2675    Users might call this function when using the TSStep() interface instead of TSSolve().
2676 
2677    Level: advanced
2678 
2679 .keywords: TS, timestep
2680 @*/
2681 PetscErrorCode TSMonitor(TS ts,PetscInt step,PetscReal ptime,Vec u)
2682 {
2683   PetscErrorCode ierr;
2684   PetscInt       i,n = ts->numbermonitors;
2685 
2686   PetscFunctionBegin;
2687   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2688   PetscValidHeaderSpecific(u,VEC_CLASSID,4);
2689   for (i=0; i<n; i++) {
2690     ierr = (*ts->monitor[i])(ts,step,ptime,u,ts->monitorcontext[i]);CHKERRQ(ierr);
2691   }
2692   PetscFunctionReturn(0);
2693 }
2694 
2695 /* ------------------------------------------------------------------------*/
2696 struct _n_TSMonitorLGCtx {
2697   PetscDrawLG lg;
2698   PetscInt    howoften;  /* when > 0 uses step % howoften, when negative only final solution plotted */
2699   PetscInt    ksp_its,snes_its;
2700 };
2701 
2702 
2703 #undef __FUNCT__
2704 #define __FUNCT__ "TSMonitorLGCtxCreate"
2705 /*@C
2706    TSMonitorLGCtxCreate - Creates a line graph context for use with
2707    TS to monitor the solution process graphically in various ways
2708 
2709    Collective on TS
2710 
2711    Input Parameters:
2712 +  host - the X display to open, or null for the local machine
2713 .  label - the title to put in the title bar
2714 .  x, y - the screen coordinates of the upper left coordinate of the window
2715 .  m, n - the screen width and height in pixels
2716 -  howoften - if positive then determines the frequency of the plotting, if -1 then only at the final time
2717 
2718    Output Parameter:
2719 .  ctx - the context
2720 
2721    Options Database Key:
2722 +  -ts_monitor_lg_timestep - automatically sets line graph monitor
2723 .  -ts_monitor_lg_solution -
2724 .  -ts_monitor_lg_error -
2725 .  -ts_monitor_lg_ksp_iterations -
2726 .  -ts_monitor_lg_snes_iterations -
2727 -  -lg_indicate_data_points <true,false> - indicate the data points (at each time step) on the plot; default is true
2728 
2729    Notes:
2730    Use TSMonitorLGCtxDestroy() to destroy.
2731 
2732    Level: intermediate
2733 
2734 .keywords: TS, monitor, line graph, residual, seealso
2735 
2736 .seealso: TSMonitorLGTimeStep(), TSMonitorSet(), TSMonitorLGSolution(), TSMonitorLGError()
2737 
2738 @*/
2739 PetscErrorCode  TSMonitorLGCtxCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscInt howoften,TSMonitorLGCtx *ctx)
2740 {
2741   PetscDraw      win;
2742   PetscErrorCode ierr;
2743   PetscBool      flg = PETSC_TRUE;
2744 
2745   PetscFunctionBegin;
2746   ierr = PetscNew(struct _n_TSMonitorLGCtx,ctx);CHKERRQ(ierr);
2747   ierr = PetscDrawCreate(comm,host,label,x,y,m,n,&win);CHKERRQ(ierr);
2748   ierr = PetscDrawSetFromOptions(win);CHKERRQ(ierr);
2749   ierr = PetscDrawLGCreate(win,1,&(*ctx)->lg);CHKERRQ(ierr);
2750   ierr = PetscOptionsGetBool(NULL,"-lg_indicate_data_points",&flg,NULL);CHKERRQ(ierr);
2751   if (flg) {
2752     ierr = PetscDrawLGIndicateDataPoints((*ctx)->lg);CHKERRQ(ierr);
2753   }
2754   ierr = PetscLogObjectParent((*ctx)->lg,win);CHKERRQ(ierr);
2755   (*ctx)->howoften = howoften;
2756   PetscFunctionReturn(0);
2757 }
2758 
2759 #undef __FUNCT__
2760 #define __FUNCT__ "TSMonitorLGTimeStep"
2761 PetscErrorCode TSMonitorLGTimeStep(TS ts,PetscInt step,PetscReal ptime,Vec v,void *monctx)
2762 {
2763   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
2764   PetscReal      x   = ptime,y;
2765   PetscErrorCode ierr;
2766 
2767   PetscFunctionBegin;
2768   if (!step) {
2769     PetscDrawAxis axis;
2770     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
2771     ierr = PetscDrawAxisSetLabels(axis,"Timestep as function of time","Time","Time step");CHKERRQ(ierr);
2772     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
2773   }
2774   ierr = TSGetTimeStep(ts,&y);CHKERRQ(ierr);
2775   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
2776   if (((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason)) {
2777     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
2778   }
2779   PetscFunctionReturn(0);
2780 }
2781 
2782 #undef __FUNCT__
2783 #define __FUNCT__ "TSMonitorLGCtxDestroy"
2784 /*@C
2785    TSMonitorLGCtxDestroy - Destroys a line graph context that was created
2786    with TSMonitorLGCtxCreate().
2787 
2788    Collective on TSMonitorLGCtx
2789 
2790    Input Parameter:
2791 .  ctx - the monitor context
2792 
2793    Level: intermediate
2794 
2795 .keywords: TS, monitor, line graph, destroy
2796 
2797 .seealso: TSMonitorLGCtxCreate(),  TSMonitorSet(), TSMonitorLGTimeStep();
2798 @*/
2799 PetscErrorCode  TSMonitorLGCtxDestroy(TSMonitorLGCtx *ctx)
2800 {
2801   PetscDraw      draw;
2802   PetscErrorCode ierr;
2803 
2804   PetscFunctionBegin;
2805   ierr = PetscDrawLGGetDraw((*ctx)->lg,&draw);CHKERRQ(ierr);
2806   ierr = PetscDrawDestroy(&draw);CHKERRQ(ierr);
2807   ierr = PetscDrawLGDestroy(&(*ctx)->lg);CHKERRQ(ierr);
2808   ierr = PetscFree(*ctx);CHKERRQ(ierr);
2809   PetscFunctionReturn(0);
2810 }
2811 
2812 #undef __FUNCT__
2813 #define __FUNCT__ "TSGetTime"
2814 /*@
2815    TSGetTime - Gets the time of the most recently completed step.
2816 
2817    Not Collective
2818 
2819    Input Parameter:
2820 .  ts - the TS context obtained from TSCreate()
2821 
2822    Output Parameter:
2823 .  t  - the current time
2824 
2825    Level: beginner
2826 
2827    Note:
2828    When called during time step evaluation (e.g. during residual evaluation or via hooks set using TSSetPreStep(),
2829    TSSetPreStage(), or TSSetPostStep()), the time is the time at the start of the step being evaluated.
2830 
2831 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
2832 
2833 .keywords: TS, get, time
2834 @*/
2835 PetscErrorCode  TSGetTime(TS ts,PetscReal *t)
2836 {
2837   PetscFunctionBegin;
2838   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2839   PetscValidRealPointer(t,2);
2840   *t = ts->ptime;
2841   PetscFunctionReturn(0);
2842 }
2843 
2844 #undef __FUNCT__
2845 #define __FUNCT__ "TSSetTime"
2846 /*@
2847    TSSetTime - Allows one to reset the time.
2848 
2849    Logically Collective on TS
2850 
2851    Input Parameters:
2852 +  ts - the TS context obtained from TSCreate()
2853 -  time - the time
2854 
2855    Level: intermediate
2856 
2857 .seealso: TSGetTime(), TSSetDuration()
2858 
2859 .keywords: TS, set, time
2860 @*/
2861 PetscErrorCode  TSSetTime(TS ts, PetscReal t)
2862 {
2863   PetscFunctionBegin;
2864   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2865   PetscValidLogicalCollectiveReal(ts,t,2);
2866   ts->ptime = t;
2867   PetscFunctionReturn(0);
2868 }
2869 
2870 #undef __FUNCT__
2871 #define __FUNCT__ "TSSetOptionsPrefix"
2872 /*@C
2873    TSSetOptionsPrefix - Sets the prefix used for searching for all
2874    TS options in the database.
2875 
2876    Logically Collective on TS
2877 
2878    Input Parameter:
2879 +  ts     - The TS context
2880 -  prefix - The prefix to prepend to all option names
2881 
2882    Notes:
2883    A hyphen (-) must NOT be given at the beginning of the prefix name.
2884    The first character of all runtime options is AUTOMATICALLY the
2885    hyphen.
2886 
2887    Level: advanced
2888 
2889 .keywords: TS, set, options, prefix, database
2890 
2891 .seealso: TSSetFromOptions()
2892 
2893 @*/
2894 PetscErrorCode  TSSetOptionsPrefix(TS ts,const char prefix[])
2895 {
2896   PetscErrorCode ierr;
2897   SNES           snes;
2898 
2899   PetscFunctionBegin;
2900   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2901   ierr = PetscObjectSetOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
2902   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2903   ierr = SNESSetOptionsPrefix(snes,prefix);CHKERRQ(ierr);
2904   PetscFunctionReturn(0);
2905 }
2906 
2907 
2908 #undef __FUNCT__
2909 #define __FUNCT__ "TSAppendOptionsPrefix"
2910 /*@C
2911    TSAppendOptionsPrefix - Appends to the prefix used for searching for all
2912    TS options in the database.
2913 
2914    Logically Collective on TS
2915 
2916    Input Parameter:
2917 +  ts     - The TS context
2918 -  prefix - The prefix to prepend to all option names
2919 
2920    Notes:
2921    A hyphen (-) must NOT be given at the beginning of the prefix name.
2922    The first character of all runtime options is AUTOMATICALLY the
2923    hyphen.
2924 
2925    Level: advanced
2926 
2927 .keywords: TS, append, options, prefix, database
2928 
2929 .seealso: TSGetOptionsPrefix()
2930 
2931 @*/
2932 PetscErrorCode  TSAppendOptionsPrefix(TS ts,const char prefix[])
2933 {
2934   PetscErrorCode ierr;
2935   SNES           snes;
2936 
2937   PetscFunctionBegin;
2938   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2939   ierr = PetscObjectAppendOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
2940   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2941   ierr = SNESAppendOptionsPrefix(snes,prefix);CHKERRQ(ierr);
2942   PetscFunctionReturn(0);
2943 }
2944 
2945 #undef __FUNCT__
2946 #define __FUNCT__ "TSGetOptionsPrefix"
2947 /*@C
2948    TSGetOptionsPrefix - Sets the prefix used for searching for all
2949    TS options in the database.
2950 
2951    Not Collective
2952 
2953    Input Parameter:
2954 .  ts - The TS context
2955 
2956    Output Parameter:
2957 .  prefix - A pointer to the prefix string used
2958 
2959    Notes: On the fortran side, the user should pass in a string 'prifix' of
2960    sufficient length to hold the prefix.
2961 
2962    Level: intermediate
2963 
2964 .keywords: TS, get, options, prefix, database
2965 
2966 .seealso: TSAppendOptionsPrefix()
2967 @*/
2968 PetscErrorCode  TSGetOptionsPrefix(TS ts,const char *prefix[])
2969 {
2970   PetscErrorCode ierr;
2971 
2972   PetscFunctionBegin;
2973   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2974   PetscValidPointer(prefix,2);
2975   ierr = PetscObjectGetOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
2976   PetscFunctionReturn(0);
2977 }
2978 
2979 #undef __FUNCT__
2980 #define __FUNCT__ "TSGetRHSJacobian"
2981 /*@C
2982    TSGetRHSJacobian - Returns the Jacobian J at the present timestep.
2983 
2984    Not Collective, but parallel objects are returned if TS is parallel
2985 
2986    Input Parameter:
2987 .  ts  - The TS context obtained from TSCreate()
2988 
2989    Output Parameters:
2990 +  Amat - The (approximate) Jacobian J of G, where U_t = G(U,t)  (or NULL)
2991 .  Pmat - The matrix from which the preconditioner is constructed, usually the same as Amat  (or NULL)
2992 .  func - Function to compute the Jacobian of the RHS  (or NULL)
2993 -  ctx - User-defined context for Jacobian evaluation routine  (or NULL)
2994 
2995    Notes: You can pass in NULL for any return argument you do not need.
2996 
2997    Level: intermediate
2998 
2999 .seealso: TSGetTimeStep(), TSGetMatrices(), TSGetTime(), TSGetTimeStepNumber()
3000 
3001 .keywords: TS, timestep, get, matrix, Jacobian
3002 @*/
3003 PetscErrorCode  TSGetRHSJacobian(TS ts,Mat *Amat,Mat *Pmat,TSRHSJacobian *func,void **ctx)
3004 {
3005   PetscErrorCode ierr;
3006   SNES           snes;
3007   DM             dm;
3008 
3009   PetscFunctionBegin;
3010   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3011   ierr = SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);CHKERRQ(ierr);
3012   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
3013   ierr = DMTSGetRHSJacobian(dm,func,ctx);CHKERRQ(ierr);
3014   PetscFunctionReturn(0);
3015 }
3016 
3017 #undef __FUNCT__
3018 #define __FUNCT__ "TSGetIJacobian"
3019 /*@C
3020    TSGetIJacobian - Returns the implicit Jacobian at the present timestep.
3021 
3022    Not Collective, but parallel objects are returned if TS is parallel
3023 
3024    Input Parameter:
3025 .  ts  - The TS context obtained from TSCreate()
3026 
3027    Output Parameters:
3028 +  Amat  - The (approximate) Jacobian of F(t,U,U_t)
3029 .  Pmat - The matrix from which the preconditioner is constructed, often the same as Amat
3030 .  f   - The function to compute the matrices
3031 - ctx - User-defined context for Jacobian evaluation routine
3032 
3033    Notes: You can pass in NULL for any return argument you do not need.
3034 
3035    Level: advanced
3036 
3037 .seealso: TSGetTimeStep(), TSGetRHSJacobian(), TSGetMatrices(), TSGetTime(), TSGetTimeStepNumber()
3038 
3039 .keywords: TS, timestep, get, matrix, Jacobian
3040 @*/
3041 PetscErrorCode  TSGetIJacobian(TS ts,Mat *Amat,Mat *Pmat,TSIJacobian *f,void **ctx)
3042 {
3043   PetscErrorCode ierr;
3044   SNES           snes;
3045   DM             dm;
3046 
3047   PetscFunctionBegin;
3048   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3049   ierr = SNESSetUpMatrices(snes);CHKERRQ(ierr);
3050   ierr = SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);CHKERRQ(ierr);
3051   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
3052   ierr = DMTSGetIJacobian(dm,f,ctx);CHKERRQ(ierr);
3053   PetscFunctionReturn(0);
3054 }
3055 
3056 
3057 #undef __FUNCT__
3058 #define __FUNCT__ "TSMonitorDrawSolution"
3059 /*@C
3060    TSMonitorDrawSolution - Monitors progress of the TS solvers by calling
3061    VecView() for the solution at each timestep
3062 
3063    Collective on TS
3064 
3065    Input Parameters:
3066 +  ts - the TS context
3067 .  step - current time-step
3068 .  ptime - current time
3069 -  dummy - either a viewer or NULL
3070 
3071    Options Database:
3072 .   -ts_monitor_draw_solution_initial - show initial solution as well as current solution
3073 
3074    Notes: the initial solution and current solution are not displayed with a common axis scaling so generally the option -ts_monitor_draw_solution_initial
3075        will look bad
3076 
3077    Level: intermediate
3078 
3079 .keywords: TS,  vector, monitor, view
3080 
3081 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3082 @*/
3083 PetscErrorCode  TSMonitorDrawSolution(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
3084 {
3085   PetscErrorCode   ierr;
3086   TSMonitorDrawCtx ictx = (TSMonitorDrawCtx)dummy;
3087   PetscDraw        draw;
3088 
3089   PetscFunctionBegin;
3090   if (!step && ictx->showinitial) {
3091     if (!ictx->initialsolution) {
3092       ierr = VecDuplicate(u,&ictx->initialsolution);CHKERRQ(ierr);
3093     }
3094     ierr = VecCopy(u,ictx->initialsolution);CHKERRQ(ierr);
3095   }
3096   if (!(((ictx->howoften > 0) && (!(step % ictx->howoften))) || ((ictx->howoften == -1) && ts->reason))) PetscFunctionReturn(0);
3097 
3098   if (ictx->showinitial) {
3099     PetscReal pause;
3100     ierr = PetscViewerDrawGetPause(ictx->viewer,&pause);CHKERRQ(ierr);
3101     ierr = PetscViewerDrawSetPause(ictx->viewer,0.0);CHKERRQ(ierr);
3102     ierr = VecView(ictx->initialsolution,ictx->viewer);CHKERRQ(ierr);
3103     ierr = PetscViewerDrawSetPause(ictx->viewer,pause);CHKERRQ(ierr);
3104     ierr = PetscViewerDrawSetHold(ictx->viewer,PETSC_TRUE);CHKERRQ(ierr);
3105   }
3106   ierr = VecView(u,ictx->viewer);CHKERRQ(ierr);
3107   if (ictx->showtimestepandtime) {
3108     PetscReal xl,yl,xr,yr,tw,w,h;
3109     char      time[32];
3110     size_t    len;
3111 
3112     ierr = PetscViewerDrawGetDraw(ictx->viewer,0,&draw);CHKERRQ(ierr);
3113     ierr = PetscSNPrintf(time,32,"Timestep %d Time %f",(int)step,(double)ptime);CHKERRQ(ierr);
3114     ierr = PetscDrawGetCoordinates(draw,&xl,&yl,&xr,&yr);CHKERRQ(ierr);
3115     ierr =  PetscStrlen(time,&len);CHKERRQ(ierr);
3116     ierr = PetscDrawStringGetSize(draw,&tw,NULL);CHKERRQ(ierr);
3117     w    = xl + .5*(xr - xl) - .5*len*tw;
3118     h    = yl + .95*(yr - yl);
3119     ierr = PetscDrawString(draw,w,h,PETSC_DRAW_BLACK,time);CHKERRQ(ierr);
3120     ierr = PetscDrawFlush(draw);CHKERRQ(ierr);
3121   }
3122 
3123   if (ictx->showinitial) {
3124     ierr = PetscViewerDrawSetHold(ictx->viewer,PETSC_FALSE);CHKERRQ(ierr);
3125   }
3126   PetscFunctionReturn(0);
3127 }
3128 
3129 #undef __FUNCT__
3130 #define __FUNCT__ "TSMonitorDrawSolutionPhase"
3131 /*@C
3132    TSMonitorDrawSolutionPhase - Monitors progress of the TS solvers by plotting the solution as a phase diagram
3133 
3134    Collective on TS
3135 
3136    Input Parameters:
3137 +  ts - the TS context
3138 .  step - current time-step
3139 .  ptime - current time
3140 -  dummy - either a viewer or NULL
3141 
3142    Level: intermediate
3143 
3144 .keywords: TS,  vector, monitor, view
3145 
3146 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3147 @*/
3148 PetscErrorCode  TSMonitorDrawSolutionPhase(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
3149 {
3150   PetscErrorCode    ierr;
3151   TSMonitorDrawCtx  ictx = (TSMonitorDrawCtx)dummy;
3152   PetscDraw         draw;
3153   MPI_Comm          comm;
3154   PetscInt          n;
3155   PetscMPIInt       size;
3156   PetscReal         xl,yl,xr,yr,tw,w,h;
3157   char              time[32];
3158   size_t            len;
3159   const PetscScalar *U;
3160 
3161   PetscFunctionBegin;
3162   ierr = PetscObjectGetComm((PetscObject)ts,&comm);CHKERRQ(ierr);
3163   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
3164   if (size != 1) SETERRQ(comm,PETSC_ERR_SUP,"Only allowed for sequential runs");
3165   ierr = VecGetSize(u,&n);CHKERRQ(ierr);
3166   if (n != 2) SETERRQ(comm,PETSC_ERR_SUP,"Only for ODEs with two unknowns");
3167 
3168   ierr = PetscViewerDrawGetDraw(ictx->viewer,0,&draw);CHKERRQ(ierr);
3169 
3170   ierr = VecGetArrayRead(u,&U);CHKERRQ(ierr);
3171   ierr = PetscDrawAxisGetLimits(ictx->axis,&xl,&xr,&yl,&yr);CHKERRQ(ierr);
3172   if ((PetscRealPart(U[0]) < xl) || (PetscRealPart(U[1]) < yl) || (PetscRealPart(U[0]) > xr) || (PetscRealPart(U[1]) > yr)) {
3173       ierr = VecRestoreArrayRead(u,&U);CHKERRQ(ierr);
3174       PetscFunctionReturn(0);
3175   }
3176   if (!step) ictx->color++;
3177   ierr = PetscDrawPoint(draw,PetscRealPart(U[0]),PetscRealPart(U[1]),ictx->color);CHKERRQ(ierr);
3178   ierr = VecRestoreArrayRead(u,&U);CHKERRQ(ierr);
3179 
3180   if (ictx->showtimestepandtime) {
3181     ierr = PetscDrawGetCoordinates(draw,&xl,&yl,&xr,&yr);CHKERRQ(ierr);
3182     ierr = PetscSNPrintf(time,32,"Timestep %d Time %f",(int)step,(double)ptime);CHKERRQ(ierr);
3183     ierr = PetscStrlen(time,&len);CHKERRQ(ierr);
3184     ierr = PetscDrawStringGetSize(draw,&tw,NULL);CHKERRQ(ierr);
3185     w    = xl + .5*(xr - xl) - .5*len*tw;
3186     h    = yl + .95*(yr - yl);
3187     ierr = PetscDrawString(draw,w,h,PETSC_DRAW_BLACK,time);CHKERRQ(ierr);
3188   }
3189   ierr = PetscDrawFlush(draw);CHKERRQ(ierr);
3190   PetscFunctionReturn(0);
3191 }
3192 
3193 
3194 #undef __FUNCT__
3195 #define __FUNCT__ "TSMonitorDrawCtxDestroy"
3196 /*@C
3197    TSMonitorDrawCtxDestroy - Destroys the monitor context for TSMonitorDrawSolution()
3198 
3199    Collective on TS
3200 
3201    Input Parameters:
3202 .    ctx - the monitor context
3203 
3204    Level: intermediate
3205 
3206 .keywords: TS,  vector, monitor, view
3207 
3208 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSMonitorDrawSolution(), TSMonitorDrawError()
3209 @*/
3210 PetscErrorCode  TSMonitorDrawCtxDestroy(TSMonitorDrawCtx *ictx)
3211 {
3212   PetscErrorCode ierr;
3213 
3214   PetscFunctionBegin;
3215   ierr = PetscDrawAxisDestroy(&(*ictx)->axis);CHKERRQ(ierr);
3216   ierr = PetscViewerDestroy(&(*ictx)->viewer);CHKERRQ(ierr);
3217   ierr = VecDestroy(&(*ictx)->initialsolution);CHKERRQ(ierr);
3218   ierr = PetscFree(*ictx);CHKERRQ(ierr);
3219   PetscFunctionReturn(0);
3220 }
3221 
3222 #undef __FUNCT__
3223 #define __FUNCT__ "TSMonitorDrawCtxCreate"
3224 /*@C
3225    TSMonitorDrawCtxCreate - Creates the monitor context for TSMonitorDrawCtx
3226 
3227    Collective on TS
3228 
3229    Input Parameter:
3230 .    ts - time-step context
3231 
3232    Output Patameter:
3233 .    ctx - the monitor context
3234 
3235    Options Database:
3236 .   -ts_monitor_draw_solution_initial - show initial solution as well as current solution
3237 
3238    Level: intermediate
3239 
3240 .keywords: TS,  vector, monitor, view
3241 
3242 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSMonitorDrawCtx()
3243 @*/
3244 PetscErrorCode  TSMonitorDrawCtxCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscInt howoften,TSMonitorDrawCtx *ctx)
3245 {
3246   PetscErrorCode   ierr;
3247 
3248   PetscFunctionBegin;
3249   ierr = PetscNew(struct _n_TSMonitorDrawCtx,ctx);CHKERRQ(ierr);
3250   ierr = PetscViewerDrawOpen(comm,host,label,x,y,m,n,&(*ctx)->viewer);CHKERRQ(ierr);
3251   ierr = PetscViewerSetFromOptions((*ctx)->viewer);CHKERRQ(ierr);
3252 
3253   (*ctx)->howoften    = howoften;
3254   (*ctx)->showinitial = PETSC_FALSE;
3255   ierr = PetscOptionsGetBool(NULL,"-ts_monitor_draw_solution_initial",&(*ctx)->showinitial,NULL);CHKERRQ(ierr);
3256 
3257   (*ctx)->showtimestepandtime = PETSC_FALSE;
3258   ierr = PetscOptionsGetBool(NULL,"-ts_monitor_draw_solution_show_time",&(*ctx)->showtimestepandtime,NULL);CHKERRQ(ierr);
3259   (*ctx)->color = PETSC_DRAW_WHITE;
3260   PetscFunctionReturn(0);
3261 }
3262 
3263 #undef __FUNCT__
3264 #define __FUNCT__ "TSMonitorDrawError"
3265 /*@C
3266    TSMonitorDrawError - Monitors progress of the TS solvers by calling
3267    VecView() for the error at each timestep
3268 
3269    Collective on TS
3270 
3271    Input Parameters:
3272 +  ts - the TS context
3273 .  step - current time-step
3274 .  ptime - current time
3275 -  dummy - either a viewer or NULL
3276 
3277    Level: intermediate
3278 
3279 .keywords: TS,  vector, monitor, view
3280 
3281 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3282 @*/
3283 PetscErrorCode  TSMonitorDrawError(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
3284 {
3285   PetscErrorCode   ierr;
3286   TSMonitorDrawCtx ctx    = (TSMonitorDrawCtx)dummy;
3287   PetscViewer      viewer = ctx->viewer;
3288   Vec              work;
3289 
3290   PetscFunctionBegin;
3291   if (!(((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason))) PetscFunctionReturn(0);
3292   ierr = VecDuplicate(u,&work);CHKERRQ(ierr);
3293   ierr = TSComputeSolutionFunction(ts,ptime,work);CHKERRQ(ierr);
3294   ierr = VecAXPY(work,-1.0,u);CHKERRQ(ierr);
3295   ierr = VecView(work,viewer);CHKERRQ(ierr);
3296   ierr = VecDestroy(&work);CHKERRQ(ierr);
3297   PetscFunctionReturn(0);
3298 }
3299 
3300 #include <petsc-private/dmimpl.h>
3301 #undef __FUNCT__
3302 #define __FUNCT__ "TSSetDM"
3303 /*@
3304    TSSetDM - Sets the DM that may be used by some preconditioners
3305 
3306    Logically Collective on TS and DM
3307 
3308    Input Parameters:
3309 +  ts - the preconditioner context
3310 -  dm - the dm
3311 
3312    Level: intermediate
3313 
3314 
3315 .seealso: TSGetDM(), SNESSetDM(), SNESGetDM()
3316 @*/
3317 PetscErrorCode  TSSetDM(TS ts,DM dm)
3318 {
3319   PetscErrorCode ierr;
3320   SNES           snes;
3321   DMTS           tsdm;
3322 
3323   PetscFunctionBegin;
3324   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3325   ierr = PetscObjectReference((PetscObject)dm);CHKERRQ(ierr);
3326   if (ts->dm) {               /* Move the DMTS context over to the new DM unless the new DM already has one */
3327     if (ts->dm->dmts && !dm->dmts) {
3328       ierr = DMCopyDMTS(ts->dm,dm);CHKERRQ(ierr);
3329       ierr = DMGetDMTS(ts->dm,&tsdm);CHKERRQ(ierr);
3330       if (tsdm->originaldm == ts->dm) { /* Grant write privileges to the replacement DM */
3331         tsdm->originaldm = dm;
3332       }
3333     }
3334     ierr = DMDestroy(&ts->dm);CHKERRQ(ierr);
3335   }
3336   ts->dm = dm;
3337 
3338   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3339   ierr = SNESSetDM(snes,dm);CHKERRQ(ierr);
3340   PetscFunctionReturn(0);
3341 }
3342 
3343 #undef __FUNCT__
3344 #define __FUNCT__ "TSGetDM"
3345 /*@
3346    TSGetDM - Gets the DM that may be used by some preconditioners
3347 
3348    Not Collective
3349 
3350    Input Parameter:
3351 . ts - the preconditioner context
3352 
3353    Output Parameter:
3354 .  dm - the dm
3355 
3356    Level: intermediate
3357 
3358 
3359 .seealso: TSSetDM(), SNESSetDM(), SNESGetDM()
3360 @*/
3361 PetscErrorCode  TSGetDM(TS ts,DM *dm)
3362 {
3363   PetscErrorCode ierr;
3364 
3365   PetscFunctionBegin;
3366   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3367   if (!ts->dm) {
3368     ierr = DMShellCreate(PetscObjectComm((PetscObject)ts),&ts->dm);CHKERRQ(ierr);
3369     if (ts->snes) {ierr = SNESSetDM(ts->snes,ts->dm);CHKERRQ(ierr);}
3370   }
3371   *dm = ts->dm;
3372   PetscFunctionReturn(0);
3373 }
3374 
3375 #undef __FUNCT__
3376 #define __FUNCT__ "SNESTSFormFunction"
3377 /*@
3378    SNESTSFormFunction - Function to evaluate nonlinear residual
3379 
3380    Logically Collective on SNES
3381 
3382    Input Parameter:
3383 + snes - nonlinear solver
3384 . U - the current state at which to evaluate the residual
3385 - ctx - user context, must be a TS
3386 
3387    Output Parameter:
3388 . F - the nonlinear residual
3389 
3390    Notes:
3391    This function is not normally called by users and is automatically registered with the SNES used by TS.
3392    It is most frequently passed to MatFDColoringSetFunction().
3393 
3394    Level: advanced
3395 
3396 .seealso: SNESSetFunction(), MatFDColoringSetFunction()
3397 @*/
3398 PetscErrorCode  SNESTSFormFunction(SNES snes,Vec U,Vec F,void *ctx)
3399 {
3400   TS             ts = (TS)ctx;
3401   PetscErrorCode ierr;
3402 
3403   PetscFunctionBegin;
3404   PetscValidHeaderSpecific(snes,SNES_CLASSID,1);
3405   PetscValidHeaderSpecific(U,VEC_CLASSID,2);
3406   PetscValidHeaderSpecific(F,VEC_CLASSID,3);
3407   PetscValidHeaderSpecific(ts,TS_CLASSID,4);
3408   ierr = (ts->ops->snesfunction)(snes,U,F,ts);CHKERRQ(ierr);
3409   PetscFunctionReturn(0);
3410 }
3411 
3412 #undef __FUNCT__
3413 #define __FUNCT__ "SNESTSFormJacobian"
3414 /*@
3415    SNESTSFormJacobian - Function to evaluate the Jacobian
3416 
3417    Collective on SNES
3418 
3419    Input Parameter:
3420 + snes - nonlinear solver
3421 . U - the current state at which to evaluate the residual
3422 - ctx - user context, must be a TS
3423 
3424    Output Parameter:
3425 + A - the Jacobian
3426 . B - the preconditioning matrix (may be the same as A)
3427 - flag - indicates any structure change in the matrix
3428 
3429    Notes:
3430    This function is not normally called by users and is automatically registered with the SNES used by TS.
3431 
3432    Level: developer
3433 
3434 .seealso: SNESSetJacobian()
3435 @*/
3436 PetscErrorCode  SNESTSFormJacobian(SNES snes,Vec U,Mat *A,Mat *B,MatStructure *flag,void *ctx)
3437 {
3438   TS             ts = (TS)ctx;
3439   PetscErrorCode ierr;
3440 
3441   PetscFunctionBegin;
3442   PetscValidHeaderSpecific(snes,SNES_CLASSID,1);
3443   PetscValidHeaderSpecific(U,VEC_CLASSID,2);
3444   PetscValidPointer(A,3);
3445   PetscValidHeaderSpecific(*A,MAT_CLASSID,3);
3446   PetscValidPointer(B,4);
3447   PetscValidHeaderSpecific(*B,MAT_CLASSID,4);
3448   PetscValidPointer(flag,5);
3449   PetscValidHeaderSpecific(ts,TS_CLASSID,6);
3450   ierr = (ts->ops->snesjacobian)(snes,U,A,B,flag,ts);CHKERRQ(ierr);
3451   PetscFunctionReturn(0);
3452 }
3453 
3454 #undef __FUNCT__
3455 #define __FUNCT__ "TSComputeRHSFunctionLinear"
3456 /*@C
3457    TSComputeRHSFunctionLinear - Evaluate the right hand side via the user-provided Jacobian, for linear problems only
3458 
3459    Collective on TS
3460 
3461    Input Arguments:
3462 +  ts - time stepping context
3463 .  t - time at which to evaluate
3464 .  U - state at which to evaluate
3465 -  ctx - context
3466 
3467    Output Arguments:
3468 .  F - right hand side
3469 
3470    Level: intermediate
3471 
3472    Notes:
3473    This function is intended to be passed to TSSetRHSFunction() to evaluate the right hand side for linear problems.
3474    The matrix (and optionally the evaluation context) should be passed to TSSetRHSJacobian().
3475 
3476 .seealso: TSSetRHSFunction(), TSSetRHSJacobian(), TSComputeRHSJacobianConstant()
3477 @*/
3478 PetscErrorCode TSComputeRHSFunctionLinear(TS ts,PetscReal t,Vec U,Vec F,void *ctx)
3479 {
3480   PetscErrorCode ierr;
3481   Mat            Arhs,Brhs;
3482   MatStructure   flg2;
3483 
3484   PetscFunctionBegin;
3485   ierr = TSGetRHSMats_Private(ts,&Arhs,&Brhs);CHKERRQ(ierr);
3486   ierr = TSComputeRHSJacobian(ts,t,U,&Arhs,&Brhs,&flg2);CHKERRQ(ierr);
3487   ierr = MatMult(Arhs,U,F);CHKERRQ(ierr);
3488   PetscFunctionReturn(0);
3489 }
3490 
3491 #undef __FUNCT__
3492 #define __FUNCT__ "TSComputeRHSJacobianConstant"
3493 /*@C
3494    TSComputeRHSJacobianConstant - Reuses a Jacobian that is time-independent.
3495 
3496    Collective on TS
3497 
3498    Input Arguments:
3499 +  ts - time stepping context
3500 .  t - time at which to evaluate
3501 .  U - state at which to evaluate
3502 -  ctx - context
3503 
3504    Output Arguments:
3505 +  A - pointer to operator
3506 .  B - pointer to preconditioning matrix
3507 -  flg - matrix structure flag
3508 
3509    Level: intermediate
3510 
3511    Notes:
3512    This function is intended to be passed to TSSetRHSJacobian() to evaluate the Jacobian for linear time-independent problems.
3513 
3514 .seealso: TSSetRHSFunction(), TSSetRHSJacobian(), TSComputeRHSFunctionLinear()
3515 @*/
3516 PetscErrorCode TSComputeRHSJacobianConstant(TS ts,PetscReal t,Vec U,Mat *A,Mat *B,MatStructure *flg,void *ctx)
3517 {
3518   PetscFunctionBegin;
3519   *flg = SAME_PRECONDITIONER;
3520   PetscFunctionReturn(0);
3521 }
3522 
3523 #undef __FUNCT__
3524 #define __FUNCT__ "TSComputeIFunctionLinear"
3525 /*@C
3526    TSComputeIFunctionLinear - Evaluate the left hand side via the user-provided Jacobian, for linear problems only
3527 
3528    Collective on TS
3529 
3530    Input Arguments:
3531 +  ts - time stepping context
3532 .  t - time at which to evaluate
3533 .  U - state at which to evaluate
3534 .  Udot - time derivative of state vector
3535 -  ctx - context
3536 
3537    Output Arguments:
3538 .  F - left hand side
3539 
3540    Level: intermediate
3541 
3542    Notes:
3543    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
3544    user is required to write their own TSComputeIFunction.
3545    This function is intended to be passed to TSSetIFunction() to evaluate the left hand side for linear problems.
3546    The matrix (and optionally the evaluation context) should be passed to TSSetIJacobian().
3547 
3548 .seealso: TSSetIFunction(), TSSetIJacobian(), TSComputeIJacobianConstant()
3549 @*/
3550 PetscErrorCode TSComputeIFunctionLinear(TS ts,PetscReal t,Vec U,Vec Udot,Vec F,void *ctx)
3551 {
3552   PetscErrorCode ierr;
3553   Mat            A,B;
3554   MatStructure   flg2;
3555 
3556   PetscFunctionBegin;
3557   ierr = TSGetIJacobian(ts,&A,&B,NULL,NULL);CHKERRQ(ierr);
3558   ierr = TSComputeIJacobian(ts,t,U,Udot,1.0,&A,&B,&flg2,PETSC_TRUE);CHKERRQ(ierr);
3559   ierr = MatMult(A,Udot,F);CHKERRQ(ierr);
3560   PetscFunctionReturn(0);
3561 }
3562 
3563 #undef __FUNCT__
3564 #define __FUNCT__ "TSComputeIJacobianConstant"
3565 /*@C
3566    TSComputeIJacobianConstant - Reuses a time-independent for a semi-implicit DAE or ODE
3567 
3568    Collective on TS
3569 
3570    Input Arguments:
3571 +  ts - time stepping context
3572 .  t - time at which to evaluate
3573 .  U - state at which to evaluate
3574 .  Udot - time derivative of state vector
3575 .  shift - shift to apply
3576 -  ctx - context
3577 
3578    Output Arguments:
3579 +  A - pointer to operator
3580 .  B - pointer to preconditioning matrix
3581 -  flg - matrix structure flag
3582 
3583    Level: advanced
3584 
3585    Notes:
3586    This function is intended to be passed to TSSetIJacobian() to evaluate the Jacobian for linear time-independent problems.
3587 
3588    It is only appropriate for problems of the form
3589 
3590 $     M Udot = F(U,t)
3591 
3592   where M is constant and F is non-stiff.  The user must pass M to TSSetIJacobian().  The current implementation only
3593   works with IMEX time integration methods such as TSROSW and TSARKIMEX, since there is no support for de-constructing
3594   an implicit operator of the form
3595 
3596 $    shift*M + J
3597 
3598   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
3599   a copy of M or reassemble it when requested.
3600 
3601 .seealso: TSSetIFunction(), TSSetIJacobian(), TSComputeIFunctionLinear()
3602 @*/
3603 PetscErrorCode TSComputeIJacobianConstant(TS ts,PetscReal t,Vec U,Vec Udot,PetscReal shift,Mat *A,Mat *B,MatStructure *flg,void *ctx)
3604 {
3605   PetscErrorCode ierr;
3606 
3607   PetscFunctionBegin;
3608   ierr = MatScale(*A, shift / ts->ijacobian.shift);CHKERRQ(ierr);
3609   ts->ijacobian.shift = shift;
3610   *flg = SAME_PRECONDITIONER;
3611   PetscFunctionReturn(0);
3612 }
3613 
3614 #undef __FUNCT__
3615 #define __FUNCT__ "TSGetEquationType"
3616 /*@
3617    TSGetEquationType - Gets the type of the equation that TS is solving.
3618 
3619    Not Collective
3620 
3621    Input Parameter:
3622 .  ts - the TS context
3623 
3624    Output Parameter:
3625 .  equation_type - see TSEquationType
3626 
3627    Level: beginner
3628 
3629 .keywords: TS, equation type
3630 
3631 .seealso: TSSetEquationType(), TSEquationType
3632 @*/
3633 PetscErrorCode  TSGetEquationType(TS ts,TSEquationType *equation_type)
3634 {
3635   PetscFunctionBegin;
3636   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3637   PetscValidPointer(equation_type,2);
3638   *equation_type = ts->equation_type;
3639   PetscFunctionReturn(0);
3640 }
3641 
3642 #undef __FUNCT__
3643 #define __FUNCT__ "TSSetEquationType"
3644 /*@
3645    TSSetEquationType - Sets the type of the equation that TS is solving.
3646 
3647    Not Collective
3648 
3649    Input Parameter:
3650 +  ts - the TS context
3651 .  equation_type - see TSEquationType
3652 
3653    Level: advanced
3654 
3655 .keywords: TS, equation type
3656 
3657 .seealso: TSGetEquationType(), TSEquationType
3658 @*/
3659 PetscErrorCode  TSSetEquationType(TS ts,TSEquationType equation_type)
3660 {
3661   PetscFunctionBegin;
3662   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3663   ts->equation_type = equation_type;
3664   PetscFunctionReturn(0);
3665 }
3666 
3667 #undef __FUNCT__
3668 #define __FUNCT__ "TSGetConvergedReason"
3669 /*@
3670    TSGetConvergedReason - Gets the reason the TS iteration was stopped.
3671 
3672    Not Collective
3673 
3674    Input Parameter:
3675 .  ts - the TS context
3676 
3677    Output Parameter:
3678 .  reason - negative value indicates diverged, positive value converged, see TSConvergedReason or the
3679             manual pages for the individual convergence tests for complete lists
3680 
3681    Level: beginner
3682 
3683    Notes:
3684    Can only be called after the call to TSSolve() is complete.
3685 
3686 .keywords: TS, nonlinear, set, convergence, test
3687 
3688 .seealso: TSSetConvergenceTest(), TSConvergedReason
3689 @*/
3690 PetscErrorCode  TSGetConvergedReason(TS ts,TSConvergedReason *reason)
3691 {
3692   PetscFunctionBegin;
3693   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3694   PetscValidPointer(reason,2);
3695   *reason = ts->reason;
3696   PetscFunctionReturn(0);
3697 }
3698 
3699 #undef __FUNCT__
3700 #define __FUNCT__ "TSSetConvergedReason"
3701 /*@
3702    TSSetConvergedReason - Sets the reason for handling the convergence of TSSolve.
3703 
3704    Not Collective
3705 
3706    Input Parameter:
3707 +  ts - the TS context
3708 .  reason - negative value indicates diverged, positive value converged, see TSConvergedReason or the
3709             manual pages for the individual convergence tests for complete lists
3710 
3711    Level: advanced
3712 
3713    Notes:
3714    Can only be called during TSSolve() is active.
3715 
3716 .keywords: TS, nonlinear, set, convergence, test
3717 
3718 .seealso: TSConvergedReason
3719 @*/
3720 PetscErrorCode  TSSetConvergedReason(TS ts,TSConvergedReason reason)
3721 {
3722   PetscFunctionBegin;
3723   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3724   ts->reason = reason;
3725   PetscFunctionReturn(0);
3726 }
3727 
3728 #undef __FUNCT__
3729 #define __FUNCT__ "TSGetSolveTime"
3730 /*@
3731    TSGetSolveTime - Gets the time after a call to TSSolve()
3732 
3733    Not Collective
3734 
3735    Input Parameter:
3736 .  ts - the TS context
3737 
3738    Output Parameter:
3739 .  ftime - the final time. This time should correspond to the final time set with TSSetDuration()
3740 
3741    Level: beginner
3742 
3743    Notes:
3744    Can only be called after the call to TSSolve() is complete.
3745 
3746 .keywords: TS, nonlinear, set, convergence, test
3747 
3748 .seealso: TSSetConvergenceTest(), TSConvergedReason
3749 @*/
3750 PetscErrorCode  TSGetSolveTime(TS ts,PetscReal *ftime)
3751 {
3752   PetscFunctionBegin;
3753   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3754   PetscValidPointer(ftime,2);
3755   *ftime = ts->solvetime;
3756   PetscFunctionReturn(0);
3757 }
3758 
3759 #undef __FUNCT__
3760 #define __FUNCT__ "TSGetSNESIterations"
3761 /*@
3762    TSGetSNESIterations - Gets the total number of nonlinear iterations
3763    used by the time integrator.
3764 
3765    Not Collective
3766 
3767    Input Parameter:
3768 .  ts - TS context
3769 
3770    Output Parameter:
3771 .  nits - number of nonlinear iterations
3772 
3773    Notes:
3774    This counter is reset to zero for each successive call to TSSolve().
3775 
3776    Level: intermediate
3777 
3778 .keywords: TS, get, number, nonlinear, iterations
3779 
3780 .seealso:  TSGetKSPIterations()
3781 @*/
3782 PetscErrorCode TSGetSNESIterations(TS ts,PetscInt *nits)
3783 {
3784   PetscFunctionBegin;
3785   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3786   PetscValidIntPointer(nits,2);
3787   *nits = ts->snes_its;
3788   PetscFunctionReturn(0);
3789 }
3790 
3791 #undef __FUNCT__
3792 #define __FUNCT__ "TSGetKSPIterations"
3793 /*@
3794    TSGetKSPIterations - Gets the total number of linear iterations
3795    used by the time integrator.
3796 
3797    Not Collective
3798 
3799    Input Parameter:
3800 .  ts - TS context
3801 
3802    Output Parameter:
3803 .  lits - number of linear iterations
3804 
3805    Notes:
3806    This counter is reset to zero for each successive call to TSSolve().
3807 
3808    Level: intermediate
3809 
3810 .keywords: TS, get, number, linear, iterations
3811 
3812 .seealso:  TSGetSNESIterations(), SNESGetKSPIterations()
3813 @*/
3814 PetscErrorCode TSGetKSPIterations(TS ts,PetscInt *lits)
3815 {
3816   PetscFunctionBegin;
3817   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3818   PetscValidIntPointer(lits,2);
3819   *lits = ts->ksp_its;
3820   PetscFunctionReturn(0);
3821 }
3822 
3823 #undef __FUNCT__
3824 #define __FUNCT__ "TSGetStepRejections"
3825 /*@
3826    TSGetStepRejections - Gets the total number of rejected steps.
3827 
3828    Not Collective
3829 
3830    Input Parameter:
3831 .  ts - TS context
3832 
3833    Output Parameter:
3834 .  rejects - number of steps rejected
3835 
3836    Notes:
3837    This counter is reset to zero for each successive call to TSSolve().
3838 
3839    Level: intermediate
3840 
3841 .keywords: TS, get, number
3842 
3843 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetSNESFailures(), TSSetMaxSNESFailures(), TSSetErrorIfStepFails()
3844 @*/
3845 PetscErrorCode TSGetStepRejections(TS ts,PetscInt *rejects)
3846 {
3847   PetscFunctionBegin;
3848   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3849   PetscValidIntPointer(rejects,2);
3850   *rejects = ts->reject;
3851   PetscFunctionReturn(0);
3852 }
3853 
3854 #undef __FUNCT__
3855 #define __FUNCT__ "TSGetSNESFailures"
3856 /*@
3857    TSGetSNESFailures - Gets the total number of failed SNES solves
3858 
3859    Not Collective
3860 
3861    Input Parameter:
3862 .  ts - TS context
3863 
3864    Output Parameter:
3865 .  fails - number of failed nonlinear solves
3866 
3867    Notes:
3868    This counter is reset to zero for each successive call to TSSolve().
3869 
3870    Level: intermediate
3871 
3872 .keywords: TS, get, number
3873 
3874 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSSetMaxSNESFailures()
3875 @*/
3876 PetscErrorCode TSGetSNESFailures(TS ts,PetscInt *fails)
3877 {
3878   PetscFunctionBegin;
3879   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3880   PetscValidIntPointer(fails,2);
3881   *fails = ts->num_snes_failures;
3882   PetscFunctionReturn(0);
3883 }
3884 
3885 #undef __FUNCT__
3886 #define __FUNCT__ "TSSetMaxStepRejections"
3887 /*@
3888    TSSetMaxStepRejections - Sets the maximum number of step rejections before a step fails
3889 
3890    Not Collective
3891 
3892    Input Parameter:
3893 +  ts - TS context
3894 -  rejects - maximum number of rejected steps, pass -1 for unlimited
3895 
3896    Notes:
3897    The counter is reset to zero for each step
3898 
3899    Options Database Key:
3900  .  -ts_max_reject - Maximum number of step rejections before a step fails
3901 
3902    Level: intermediate
3903 
3904 .keywords: TS, set, maximum, number
3905 
3906 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxSNESFailures(), TSGetStepRejections(), TSGetSNESFailures(), TSSetErrorIfStepFails(), TSGetConvergedReason()
3907 @*/
3908 PetscErrorCode TSSetMaxStepRejections(TS ts,PetscInt rejects)
3909 {
3910   PetscFunctionBegin;
3911   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3912   ts->max_reject = rejects;
3913   PetscFunctionReturn(0);
3914 }
3915 
3916 #undef __FUNCT__
3917 #define __FUNCT__ "TSSetMaxSNESFailures"
3918 /*@
3919    TSSetMaxSNESFailures - Sets the maximum number of failed SNES solves
3920 
3921    Not Collective
3922 
3923    Input Parameter:
3924 +  ts - TS context
3925 -  fails - maximum number of failed nonlinear solves, pass -1 for unlimited
3926 
3927    Notes:
3928    The counter is reset to zero for each successive call to TSSolve().
3929 
3930    Options Database Key:
3931  .  -ts_max_snes_failures - Maximum number of nonlinear solve failures
3932 
3933    Level: intermediate
3934 
3935 .keywords: TS, set, maximum, number
3936 
3937 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSGetSNESFailures(), SNESGetConvergedReason(), TSGetConvergedReason()
3938 @*/
3939 PetscErrorCode TSSetMaxSNESFailures(TS ts,PetscInt fails)
3940 {
3941   PetscFunctionBegin;
3942   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3943   ts->max_snes_failures = fails;
3944   PetscFunctionReturn(0);
3945 }
3946 
3947 #undef __FUNCT__
3948 #define __FUNCT__ "TSSetErrorIfStepFails()"
3949 /*@
3950    TSSetErrorIfStepFails - Error if no step succeeds
3951 
3952    Not Collective
3953 
3954    Input Parameter:
3955 +  ts - TS context
3956 -  err - PETSC_TRUE to error if no step succeeds, PETSC_FALSE to return without failure
3957 
3958    Options Database Key:
3959  .  -ts_error_if_step_fails - Error if no step succeeds
3960 
3961    Level: intermediate
3962 
3963 .keywords: TS, set, error
3964 
3965 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSGetSNESFailures(), TSSetErrorIfStepFails(), TSGetConvergedReason()
3966 @*/
3967 PetscErrorCode TSSetErrorIfStepFails(TS ts,PetscBool err)
3968 {
3969   PetscFunctionBegin;
3970   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3971   ts->errorifstepfailed = err;
3972   PetscFunctionReturn(0);
3973 }
3974 
3975 #undef __FUNCT__
3976 #define __FUNCT__ "TSMonitorSolutionBinary"
3977 /*@C
3978    TSMonitorSolutionBinary - Monitors progress of the TS solvers by VecView() for the solution at each timestep. Normally the viewer is a binary file
3979 
3980    Collective on TS
3981 
3982    Input Parameters:
3983 +  ts - the TS context
3984 .  step - current time-step
3985 .  ptime - current time
3986 .  u - current state
3987 -  viewer - binary viewer
3988 
3989    Level: intermediate
3990 
3991 .keywords: TS,  vector, monitor, view
3992 
3993 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3994 @*/
3995 PetscErrorCode  TSMonitorSolutionBinary(TS ts,PetscInt step,PetscReal ptime,Vec u,void *viewer)
3996 {
3997   PetscErrorCode ierr;
3998   PetscViewer    v = (PetscViewer)viewer;
3999 
4000   PetscFunctionBegin;
4001   ierr = VecView(u,v);CHKERRQ(ierr);
4002   PetscFunctionReturn(0);
4003 }
4004 
4005 #undef __FUNCT__
4006 #define __FUNCT__ "TSMonitorSolutionVTK"
4007 /*@C
4008    TSMonitorSolutionVTK - Monitors progress of the TS solvers by VecView() for the solution at each timestep.
4009 
4010    Collective on TS
4011 
4012    Input Parameters:
4013 +  ts - the TS context
4014 .  step - current time-step
4015 .  ptime - current time
4016 .  u - current state
4017 -  filenametemplate - string containing a format specifier for the integer time step (e.g. %03D)
4018 
4019    Level: intermediate
4020 
4021    Notes:
4022    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.
4023    These are named according to the file name template.
4024 
4025    This function is normally passed as an argument to TSMonitorSet() along with TSMonitorSolutionVTKDestroy().
4026 
4027 .keywords: TS,  vector, monitor, view
4028 
4029 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
4030 @*/
4031 PetscErrorCode TSMonitorSolutionVTK(TS ts,PetscInt step,PetscReal ptime,Vec u,void *filenametemplate)
4032 {
4033   PetscErrorCode ierr;
4034   char           filename[PETSC_MAX_PATH_LEN];
4035   PetscViewer    viewer;
4036 
4037   PetscFunctionBegin;
4038   ierr = PetscSNPrintf(filename,sizeof(filename),(const char*)filenametemplate,step);CHKERRQ(ierr);
4039   ierr = PetscViewerVTKOpen(PetscObjectComm((PetscObject)ts),filename,FILE_MODE_WRITE,&viewer);CHKERRQ(ierr);
4040   ierr = VecView(u,viewer);CHKERRQ(ierr);
4041   ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
4042   PetscFunctionReturn(0);
4043 }
4044 
4045 #undef __FUNCT__
4046 #define __FUNCT__ "TSMonitorSolutionVTKDestroy"
4047 /*@C
4048    TSMonitorSolutionVTKDestroy - Destroy context for monitoring
4049 
4050    Collective on TS
4051 
4052    Input Parameters:
4053 .  filenametemplate - string containing a format specifier for the integer time step (e.g. %03D)
4054 
4055    Level: intermediate
4056 
4057    Note:
4058    This function is normally passed to TSMonitorSet() along with TSMonitorSolutionVTK().
4059 
4060 .keywords: TS,  vector, monitor, view
4061 
4062 .seealso: TSMonitorSet(), TSMonitorSolutionVTK()
4063 @*/
4064 PetscErrorCode TSMonitorSolutionVTKDestroy(void *filenametemplate)
4065 {
4066   PetscErrorCode ierr;
4067 
4068   PetscFunctionBegin;
4069   ierr = PetscFree(*(char**)filenametemplate);CHKERRQ(ierr);
4070   PetscFunctionReturn(0);
4071 }
4072 
4073 #undef __FUNCT__
4074 #define __FUNCT__ "TSGetAdapt"
4075 /*@
4076    TSGetAdapt - Get the adaptive controller context for the current method
4077 
4078    Collective on TS if controller has not been created yet
4079 
4080    Input Arguments:
4081 .  ts - time stepping context
4082 
4083    Output Arguments:
4084 .  adapt - adaptive controller
4085 
4086    Level: intermediate
4087 
4088 .seealso: TSAdapt, TSAdaptSetType(), TSAdaptChoose()
4089 @*/
4090 PetscErrorCode TSGetAdapt(TS ts,TSAdapt *adapt)
4091 {
4092   PetscErrorCode ierr;
4093 
4094   PetscFunctionBegin;
4095   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4096   PetscValidPointer(adapt,2);
4097   if (!ts->adapt) {
4098     ierr = TSAdaptCreate(PetscObjectComm((PetscObject)ts),&ts->adapt);CHKERRQ(ierr);
4099     ierr = PetscLogObjectParent(ts,ts->adapt);CHKERRQ(ierr);
4100     ierr = PetscObjectIncrementTabLevel((PetscObject)ts->adapt,(PetscObject)ts,1);CHKERRQ(ierr);
4101   }
4102   *adapt = ts->adapt;
4103   PetscFunctionReturn(0);
4104 }
4105 
4106 #undef __FUNCT__
4107 #define __FUNCT__ "TSSetTolerances"
4108 /*@
4109    TSSetTolerances - Set tolerances for local truncation error when using adaptive controller
4110 
4111    Logically Collective
4112 
4113    Input Arguments:
4114 +  ts - time integration context
4115 .  atol - scalar absolute tolerances, PETSC_DECIDE to leave current value
4116 .  vatol - vector of absolute tolerances or NULL, used in preference to atol if present
4117 .  rtol - scalar relative tolerances, PETSC_DECIDE to leave current value
4118 -  vrtol - vector of relative tolerances or NULL, used in preference to atol if present
4119 
4120    Level: beginner
4121 
4122 .seealso: TS, TSAdapt, TSVecNormWRMS(), TSGetTolerances()
4123 @*/
4124 PetscErrorCode TSSetTolerances(TS ts,PetscReal atol,Vec vatol,PetscReal rtol,Vec vrtol)
4125 {
4126   PetscErrorCode ierr;
4127 
4128   PetscFunctionBegin;
4129   if (atol != PETSC_DECIDE && atol != PETSC_DEFAULT) ts->atol = atol;
4130   if (vatol) {
4131     ierr = PetscObjectReference((PetscObject)vatol);CHKERRQ(ierr);
4132     ierr = VecDestroy(&ts->vatol);CHKERRQ(ierr);
4133 
4134     ts->vatol = vatol;
4135   }
4136   if (rtol != PETSC_DECIDE && rtol != PETSC_DEFAULT) ts->rtol = rtol;
4137   if (vrtol) {
4138     ierr = PetscObjectReference((PetscObject)vrtol);CHKERRQ(ierr);
4139     ierr = VecDestroy(&ts->vrtol);CHKERRQ(ierr);
4140 
4141     ts->vrtol = vrtol;
4142   }
4143   PetscFunctionReturn(0);
4144 }
4145 
4146 #undef __FUNCT__
4147 #define __FUNCT__ "TSGetTolerances"
4148 /*@
4149    TSGetTolerances - Get tolerances for local truncation error when using adaptive controller
4150 
4151    Logically Collective
4152 
4153    Input Arguments:
4154 .  ts - time integration context
4155 
4156    Output Arguments:
4157 +  atol - scalar absolute tolerances, NULL to ignore
4158 .  vatol - vector of absolute tolerances, NULL to ignore
4159 .  rtol - scalar relative tolerances, NULL to ignore
4160 -  vrtol - vector of relative tolerances, NULL to ignore
4161 
4162    Level: beginner
4163 
4164 .seealso: TS, TSAdapt, TSVecNormWRMS(), TSSetTolerances()
4165 @*/
4166 PetscErrorCode TSGetTolerances(TS ts,PetscReal *atol,Vec *vatol,PetscReal *rtol,Vec *vrtol)
4167 {
4168   PetscFunctionBegin;
4169   if (atol)  *atol  = ts->atol;
4170   if (vatol) *vatol = ts->vatol;
4171   if (rtol)  *rtol  = ts->rtol;
4172   if (vrtol) *vrtol = ts->vrtol;
4173   PetscFunctionReturn(0);
4174 }
4175 
4176 #undef __FUNCT__
4177 #define __FUNCT__ "TSErrorNormWRMS"
4178 /*@
4179    TSErrorNormWRMS - compute a weighted norm of the difference between a vector and the current state
4180 
4181    Collective on TS
4182 
4183    Input Arguments:
4184 +  ts - time stepping context
4185 -  Y - state vector to be compared to ts->vec_sol
4186 
4187    Output Arguments:
4188 .  norm - weighted norm, a value of 1.0 is considered small
4189 
4190    Level: developer
4191 
4192 .seealso: TSSetTolerances()
4193 @*/
4194 PetscErrorCode TSErrorNormWRMS(TS ts,Vec Y,PetscReal *norm)
4195 {
4196   PetscErrorCode    ierr;
4197   PetscInt          i,n,N;
4198   const PetscScalar *u,*y;
4199   Vec               U;
4200   PetscReal         sum,gsum;
4201 
4202   PetscFunctionBegin;
4203   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4204   PetscValidHeaderSpecific(Y,VEC_CLASSID,2);
4205   PetscValidPointer(norm,3);
4206   U = ts->vec_sol;
4207   PetscCheckSameTypeAndComm(U,1,Y,2);
4208   if (U == Y) SETERRQ(PetscObjectComm((PetscObject)U),PETSC_ERR_ARG_IDN,"Y cannot be the TS solution vector");
4209 
4210   ierr = VecGetSize(U,&N);CHKERRQ(ierr);
4211   ierr = VecGetLocalSize(U,&n);CHKERRQ(ierr);
4212   ierr = VecGetArrayRead(U,&u);CHKERRQ(ierr);
4213   ierr = VecGetArrayRead(Y,&y);CHKERRQ(ierr);
4214   sum  = 0.;
4215   if (ts->vatol && ts->vrtol) {
4216     const PetscScalar *atol,*rtol;
4217     ierr = VecGetArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4218     ierr = VecGetArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4219     for (i=0; i<n; i++) {
4220       PetscReal tol = PetscRealPart(atol[i]) + PetscRealPart(rtol[i]) * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4221       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4222     }
4223     ierr = VecRestoreArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4224     ierr = VecRestoreArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4225   } else if (ts->vatol) {       /* vector atol, scalar rtol */
4226     const PetscScalar *atol;
4227     ierr = VecGetArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4228     for (i=0; i<n; i++) {
4229       PetscReal tol = PetscRealPart(atol[i]) + ts->rtol * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4230       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4231     }
4232     ierr = VecRestoreArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
4233   } else if (ts->vrtol) {       /* scalar atol, vector rtol */
4234     const PetscScalar *rtol;
4235     ierr = VecGetArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4236     for (i=0; i<n; i++) {
4237       PetscReal tol = ts->atol + PetscRealPart(rtol[i]) * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4238       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4239     }
4240     ierr = VecRestoreArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
4241   } else {                      /* scalar atol, scalar rtol */
4242     for (i=0; i<n; i++) {
4243       PetscReal tol = ts->atol + ts->rtol * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
4244       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
4245     }
4246   }
4247   ierr = VecRestoreArrayRead(U,&u);CHKERRQ(ierr);
4248   ierr = VecRestoreArrayRead(Y,&y);CHKERRQ(ierr);
4249 
4250   ierr  = MPI_Allreduce(&sum,&gsum,1,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)ts));CHKERRQ(ierr);
4251   *norm = PetscSqrtReal(gsum / N);
4252   if (PetscIsInfOrNanScalar(*norm)) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_FP,"Infinite or not-a-number generated in norm");
4253   PetscFunctionReturn(0);
4254 }
4255 
4256 #undef __FUNCT__
4257 #define __FUNCT__ "TSSetCFLTimeLocal"
4258 /*@
4259    TSSetCFLTimeLocal - Set the local CFL constraint relative to forward Euler
4260 
4261    Logically Collective on TS
4262 
4263    Input Arguments:
4264 +  ts - time stepping context
4265 -  cfltime - maximum stable time step if using forward Euler (value can be different on each process)
4266 
4267    Note:
4268    After calling this function, the global CFL time can be obtained by calling TSGetCFLTime()
4269 
4270    Level: intermediate
4271 
4272 .seealso: TSGetCFLTime(), TSADAPTCFL
4273 @*/
4274 PetscErrorCode TSSetCFLTimeLocal(TS ts,PetscReal cfltime)
4275 {
4276   PetscFunctionBegin;
4277   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4278   ts->cfltime_local = cfltime;
4279   ts->cfltime       = -1.;
4280   PetscFunctionReturn(0);
4281 }
4282 
4283 #undef __FUNCT__
4284 #define __FUNCT__ "TSGetCFLTime"
4285 /*@
4286    TSGetCFLTime - Get the maximum stable time step according to CFL criteria applied to forward Euler
4287 
4288    Collective on TS
4289 
4290    Input Arguments:
4291 .  ts - time stepping context
4292 
4293    Output Arguments:
4294 .  cfltime - maximum stable time step for forward Euler
4295 
4296    Level: advanced
4297 
4298 .seealso: TSSetCFLTimeLocal()
4299 @*/
4300 PetscErrorCode TSGetCFLTime(TS ts,PetscReal *cfltime)
4301 {
4302   PetscErrorCode ierr;
4303 
4304   PetscFunctionBegin;
4305   if (ts->cfltime < 0) {
4306     ierr = MPI_Allreduce(&ts->cfltime_local,&ts->cfltime,1,MPIU_REAL,MPIU_MIN,PetscObjectComm((PetscObject)ts));CHKERRQ(ierr);
4307   }
4308   *cfltime = ts->cfltime;
4309   PetscFunctionReturn(0);
4310 }
4311 
4312 #undef __FUNCT__
4313 #define __FUNCT__ "TSVISetVariableBounds"
4314 /*@
4315    TSVISetVariableBounds - Sets the lower and upper bounds for the solution vector. xl <= x <= xu
4316 
4317    Input Parameters:
4318 .  ts   - the TS context.
4319 .  xl   - lower bound.
4320 .  xu   - upper bound.
4321 
4322    Notes:
4323    If this routine is not called then the lower and upper bounds are set to
4324    SNES_VI_NINF and SNES_VI_INF respectively during SNESSetUp().
4325 
4326    Level: advanced
4327 
4328 @*/
4329 PetscErrorCode TSVISetVariableBounds(TS ts, Vec xl, Vec xu)
4330 {
4331   PetscErrorCode ierr;
4332   SNES           snes;
4333 
4334   PetscFunctionBegin;
4335   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
4336   ierr = SNESVISetVariableBounds(snes,xl,xu);CHKERRQ(ierr);
4337   PetscFunctionReturn(0);
4338 }
4339 
4340 #if defined(PETSC_HAVE_MATLAB_ENGINE)
4341 #include <mex.h>
4342 
4343 typedef struct {char *funcname; mxArray *ctx;} TSMatlabContext;
4344 
4345 #undef __FUNCT__
4346 #define __FUNCT__ "TSComputeFunction_Matlab"
4347 /*
4348    TSComputeFunction_Matlab - Calls the function that has been set with
4349                          TSSetFunctionMatlab().
4350 
4351    Collective on TS
4352 
4353    Input Parameters:
4354 +  snes - the TS context
4355 -  u - input vector
4356 
4357    Output Parameter:
4358 .  y - function vector, as set by TSSetFunction()
4359 
4360    Notes:
4361    TSComputeFunction() is typically used within nonlinear solvers
4362    implementations, so most users would not generally call this routine
4363    themselves.
4364 
4365    Level: developer
4366 
4367 .keywords: TS, nonlinear, compute, function
4368 
4369 .seealso: TSSetFunction(), TSGetFunction()
4370 */
4371 PetscErrorCode  TSComputeFunction_Matlab(TS snes,PetscReal time,Vec u,Vec udot,Vec y, void *ctx)
4372 {
4373   PetscErrorCode  ierr;
4374   TSMatlabContext *sctx = (TSMatlabContext*)ctx;
4375   int             nlhs  = 1,nrhs = 7;
4376   mxArray         *plhs[1],*prhs[7];
4377   long long int   lx = 0,lxdot = 0,ly = 0,ls = 0;
4378 
4379   PetscFunctionBegin;
4380   PetscValidHeaderSpecific(snes,TS_CLASSID,1);
4381   PetscValidHeaderSpecific(u,VEC_CLASSID,3);
4382   PetscValidHeaderSpecific(udot,VEC_CLASSID,4);
4383   PetscValidHeaderSpecific(y,VEC_CLASSID,5);
4384   PetscCheckSameComm(snes,1,u,3);
4385   PetscCheckSameComm(snes,1,y,5);
4386 
4387   ierr = PetscMemcpy(&ls,&snes,sizeof(snes));CHKERRQ(ierr);
4388   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4389   ierr = PetscMemcpy(&lxdot,&udot,sizeof(udot));CHKERRQ(ierr);
4390   ierr = PetscMemcpy(&ly,&y,sizeof(u));CHKERRQ(ierr);
4391 
4392   prhs[0] =  mxCreateDoubleScalar((double)ls);
4393   prhs[1] =  mxCreateDoubleScalar(time);
4394   prhs[2] =  mxCreateDoubleScalar((double)lx);
4395   prhs[3] =  mxCreateDoubleScalar((double)lxdot);
4396   prhs[4] =  mxCreateDoubleScalar((double)ly);
4397   prhs[5] =  mxCreateString(sctx->funcname);
4398   prhs[6] =  sctx->ctx;
4399   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSComputeFunctionInternal");CHKERRQ(ierr);
4400   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4401   mxDestroyArray(prhs[0]);
4402   mxDestroyArray(prhs[1]);
4403   mxDestroyArray(prhs[2]);
4404   mxDestroyArray(prhs[3]);
4405   mxDestroyArray(prhs[4]);
4406   mxDestroyArray(prhs[5]);
4407   mxDestroyArray(plhs[0]);
4408   PetscFunctionReturn(0);
4409 }
4410 
4411 
4412 #undef __FUNCT__
4413 #define __FUNCT__ "TSSetFunctionMatlab"
4414 /*
4415    TSSetFunctionMatlab - Sets the function evaluation routine and function
4416    vector for use by the TS routines in solving ODEs
4417    equations from MATLAB. Here the function is a string containing the name of a MATLAB function
4418 
4419    Logically Collective on TS
4420 
4421    Input Parameters:
4422 +  ts - the TS context
4423 -  func - function evaluation routine
4424 
4425    Calling sequence of func:
4426 $    func (TS ts,PetscReal time,Vec u,Vec udot,Vec f,void *ctx);
4427 
4428    Level: beginner
4429 
4430 .keywords: TS, nonlinear, set, function
4431 
4432 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4433 */
4434 PetscErrorCode  TSSetFunctionMatlab(TS ts,const char *func,mxArray *ctx)
4435 {
4436   PetscErrorCode  ierr;
4437   TSMatlabContext *sctx;
4438 
4439   PetscFunctionBegin;
4440   /* currently sctx is memory bleed */
4441   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4442   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4443   /*
4444      This should work, but it doesn't
4445   sctx->ctx = ctx;
4446   mexMakeArrayPersistent(sctx->ctx);
4447   */
4448   sctx->ctx = mxDuplicateArray(ctx);
4449 
4450   ierr = TSSetIFunction(ts,NULL,TSComputeFunction_Matlab,sctx);CHKERRQ(ierr);
4451   PetscFunctionReturn(0);
4452 }
4453 
4454 #undef __FUNCT__
4455 #define __FUNCT__ "TSComputeJacobian_Matlab"
4456 /*
4457    TSComputeJacobian_Matlab - Calls the function that has been set with
4458                          TSSetJacobianMatlab().
4459 
4460    Collective on TS
4461 
4462    Input Parameters:
4463 +  ts - the TS context
4464 .  u - input vector
4465 .  A, B - the matrices
4466 -  ctx - user context
4467 
4468    Output Parameter:
4469 .  flag - structure of the matrix
4470 
4471    Level: developer
4472 
4473 .keywords: TS, nonlinear, compute, function
4474 
4475 .seealso: TSSetFunction(), TSGetFunction()
4476 @*/
4477 PetscErrorCode  TSComputeJacobian_Matlab(TS ts,PetscReal time,Vec u,Vec udot,PetscReal shift,Mat *A,Mat *B,MatStructure *flag, void *ctx)
4478 {
4479   PetscErrorCode  ierr;
4480   TSMatlabContext *sctx = (TSMatlabContext*)ctx;
4481   int             nlhs  = 2,nrhs = 9;
4482   mxArray         *plhs[2],*prhs[9];
4483   long long int   lx = 0,lxdot = 0,lA = 0,ls = 0, lB = 0;
4484 
4485   PetscFunctionBegin;
4486   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4487   PetscValidHeaderSpecific(u,VEC_CLASSID,3);
4488 
4489   /* call Matlab function in ctx with arguments u and y */
4490 
4491   ierr = PetscMemcpy(&ls,&ts,sizeof(ts));CHKERRQ(ierr);
4492   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4493   ierr = PetscMemcpy(&lxdot,&udot,sizeof(u));CHKERRQ(ierr);
4494   ierr = PetscMemcpy(&lA,A,sizeof(u));CHKERRQ(ierr);
4495   ierr = PetscMemcpy(&lB,B,sizeof(u));CHKERRQ(ierr);
4496 
4497   prhs[0] =  mxCreateDoubleScalar((double)ls);
4498   prhs[1] =  mxCreateDoubleScalar((double)time);
4499   prhs[2] =  mxCreateDoubleScalar((double)lx);
4500   prhs[3] =  mxCreateDoubleScalar((double)lxdot);
4501   prhs[4] =  mxCreateDoubleScalar((double)shift);
4502   prhs[5] =  mxCreateDoubleScalar((double)lA);
4503   prhs[6] =  mxCreateDoubleScalar((double)lB);
4504   prhs[7] =  mxCreateString(sctx->funcname);
4505   prhs[8] =  sctx->ctx;
4506   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSComputeJacobianInternal");CHKERRQ(ierr);
4507   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4508   *flag   =  (MatStructure) mxGetScalar(plhs[1]);CHKERRQ(ierr);
4509   mxDestroyArray(prhs[0]);
4510   mxDestroyArray(prhs[1]);
4511   mxDestroyArray(prhs[2]);
4512   mxDestroyArray(prhs[3]);
4513   mxDestroyArray(prhs[4]);
4514   mxDestroyArray(prhs[5]);
4515   mxDestroyArray(prhs[6]);
4516   mxDestroyArray(prhs[7]);
4517   mxDestroyArray(plhs[0]);
4518   mxDestroyArray(plhs[1]);
4519   PetscFunctionReturn(0);
4520 }
4521 
4522 
4523 #undef __FUNCT__
4524 #define __FUNCT__ "TSSetJacobianMatlab"
4525 /*
4526    TSSetJacobianMatlab - Sets the Jacobian function evaluation routine and two empty Jacobian matrices
4527    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
4528 
4529    Logically Collective on TS
4530 
4531    Input Parameters:
4532 +  ts - the TS context
4533 .  A,B - Jacobian matrices
4534 .  func - function evaluation routine
4535 -  ctx - user context
4536 
4537    Calling sequence of func:
4538 $    flag = func (TS ts,PetscReal time,Vec u,Vec udot,Mat A,Mat B,void *ctx);
4539 
4540 
4541    Level: developer
4542 
4543 .keywords: TS, nonlinear, set, function
4544 
4545 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4546 */
4547 PetscErrorCode  TSSetJacobianMatlab(TS ts,Mat A,Mat B,const char *func,mxArray *ctx)
4548 {
4549   PetscErrorCode  ierr;
4550   TSMatlabContext *sctx;
4551 
4552   PetscFunctionBegin;
4553   /* currently sctx is memory bleed */
4554   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4555   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4556   /*
4557      This should work, but it doesn't
4558   sctx->ctx = ctx;
4559   mexMakeArrayPersistent(sctx->ctx);
4560   */
4561   sctx->ctx = mxDuplicateArray(ctx);
4562 
4563   ierr = TSSetIJacobian(ts,A,B,TSComputeJacobian_Matlab,sctx);CHKERRQ(ierr);
4564   PetscFunctionReturn(0);
4565 }
4566 
4567 #undef __FUNCT__
4568 #define __FUNCT__ "TSMonitor_Matlab"
4569 /*
4570    TSMonitor_Matlab - Calls the function that has been set with TSMonitorSetMatlab().
4571 
4572    Collective on TS
4573 
4574 .seealso: TSSetFunction(), TSGetFunction()
4575 @*/
4576 PetscErrorCode  TSMonitor_Matlab(TS ts,PetscInt it, PetscReal time,Vec u, void *ctx)
4577 {
4578   PetscErrorCode  ierr;
4579   TSMatlabContext *sctx = (TSMatlabContext*)ctx;
4580   int             nlhs  = 1,nrhs = 6;
4581   mxArray         *plhs[1],*prhs[6];
4582   long long int   lx = 0,ls = 0;
4583 
4584   PetscFunctionBegin;
4585   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4586   PetscValidHeaderSpecific(u,VEC_CLASSID,4);
4587 
4588   ierr = PetscMemcpy(&ls,&ts,sizeof(ts));CHKERRQ(ierr);
4589   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4590 
4591   prhs[0] =  mxCreateDoubleScalar((double)ls);
4592   prhs[1] =  mxCreateDoubleScalar((double)it);
4593   prhs[2] =  mxCreateDoubleScalar((double)time);
4594   prhs[3] =  mxCreateDoubleScalar((double)lx);
4595   prhs[4] =  mxCreateString(sctx->funcname);
4596   prhs[5] =  sctx->ctx;
4597   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSMonitorInternal");CHKERRQ(ierr);
4598   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4599   mxDestroyArray(prhs[0]);
4600   mxDestroyArray(prhs[1]);
4601   mxDestroyArray(prhs[2]);
4602   mxDestroyArray(prhs[3]);
4603   mxDestroyArray(prhs[4]);
4604   mxDestroyArray(plhs[0]);
4605   PetscFunctionReturn(0);
4606 }
4607 
4608 
4609 #undef __FUNCT__
4610 #define __FUNCT__ "TSMonitorSetMatlab"
4611 /*
4612    TSMonitorSetMatlab - Sets the monitor function from Matlab
4613 
4614    Level: developer
4615 
4616 .keywords: TS, nonlinear, set, function
4617 
4618 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4619 */
4620 PetscErrorCode  TSMonitorSetMatlab(TS ts,const char *func,mxArray *ctx)
4621 {
4622   PetscErrorCode  ierr;
4623   TSMatlabContext *sctx;
4624 
4625   PetscFunctionBegin;
4626   /* currently sctx is memory bleed */
4627   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4628   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4629   /*
4630      This should work, but it doesn't
4631   sctx->ctx = ctx;
4632   mexMakeArrayPersistent(sctx->ctx);
4633   */
4634   sctx->ctx = mxDuplicateArray(ctx);
4635 
4636   ierr = TSMonitorSet(ts,TSMonitor_Matlab,sctx,NULL);CHKERRQ(ierr);
4637   PetscFunctionReturn(0);
4638 }
4639 #endif
4640 
4641 
4642 
4643 #undef __FUNCT__
4644 #define __FUNCT__ "TSMonitorLGSolution"
4645 /*@C
4646    TSMonitorLGSolution - Monitors progress of the TS solvers by plotting each component of the solution vector
4647        in a time based line graph
4648 
4649    Collective on TS
4650 
4651    Input Parameters:
4652 +  ts - the TS context
4653 .  step - current time-step
4654 .  ptime - current time
4655 -  lg - a line graph object
4656 
4657    Level: intermediate
4658 
4659     Notes: each process in a parallel run displays its component solutions in a separate window
4660 
4661 .keywords: TS,  vector, monitor, view
4662 
4663 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
4664 @*/
4665 PetscErrorCode  TSMonitorLGSolution(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
4666 {
4667   PetscErrorCode    ierr;
4668   TSMonitorLGCtx    ctx = (TSMonitorLGCtx)dummy;
4669   const PetscScalar *yy;
4670   PetscInt          dim;
4671 
4672   PetscFunctionBegin;
4673   if (!step) {
4674     PetscDrawAxis axis;
4675     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4676     ierr = PetscDrawAxisSetLabels(axis,"Solution as function of time","Time","Solution");CHKERRQ(ierr);
4677     ierr = VecGetLocalSize(u,&dim);CHKERRQ(ierr);
4678     ierr = PetscDrawLGSetDimension(ctx->lg,dim);CHKERRQ(ierr);
4679     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4680   }
4681   ierr = VecGetArrayRead(u,&yy);CHKERRQ(ierr);
4682 #if defined(PETSC_USE_COMPLEX)
4683   {
4684     PetscReal *yreal;
4685     PetscInt  i,n;
4686     ierr = VecGetLocalSize(u,&n);CHKERRQ(ierr);
4687     ierr = PetscMalloc(n*sizeof(PetscReal),&yreal);CHKERRQ(ierr);
4688     for (i=0; i<n; i++) yreal[i] = PetscRealPart(yy[i]);
4689     ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yreal);CHKERRQ(ierr);
4690     ierr = PetscFree(yreal);CHKERRQ(ierr);
4691   }
4692 #else
4693   ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yy);CHKERRQ(ierr);
4694 #endif
4695   ierr = VecRestoreArrayRead(u,&yy);CHKERRQ(ierr);
4696   if (((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason)) {
4697     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4698   }
4699   PetscFunctionReturn(0);
4700 }
4701 
4702 #undef __FUNCT__
4703 #define __FUNCT__ "TSMonitorLGError"
4704 /*@C
4705    TSMonitorLGError - Monitors progress of the TS solvers by plotting each component of the solution vector
4706        in a time based line graph
4707 
4708    Collective on TS
4709 
4710    Input Parameters:
4711 +  ts - the TS context
4712 .  step - current time-step
4713 .  ptime - current time
4714 -  lg - a line graph object
4715 
4716    Level: intermediate
4717 
4718    Notes:
4719    Only for sequential solves.
4720 
4721    The user must provide the solution using TSSetSolutionFunction() to use this monitor.
4722 
4723    Options Database Keys:
4724 .  -ts_monitor_lg_error - create a graphical monitor of error history
4725 
4726 .keywords: TS,  vector, monitor, view
4727 
4728 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSSetSolutionFunction()
4729 @*/
4730 PetscErrorCode  TSMonitorLGError(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
4731 {
4732   PetscErrorCode    ierr;
4733   TSMonitorLGCtx    ctx = (TSMonitorLGCtx)dummy;
4734   const PetscScalar *yy;
4735   Vec               y;
4736   PetscInt          dim;
4737 
4738   PetscFunctionBegin;
4739   if (!step) {
4740     PetscDrawAxis axis;
4741     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4742     ierr = PetscDrawAxisSetLabels(axis,"Error in solution as function of time","Time","Solution");CHKERRQ(ierr);
4743     ierr = VecGetLocalSize(u,&dim);CHKERRQ(ierr);
4744     ierr = PetscDrawLGSetDimension(ctx->lg,dim);CHKERRQ(ierr);
4745     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4746   }
4747   ierr = VecDuplicate(u,&y);CHKERRQ(ierr);
4748   ierr = TSComputeSolutionFunction(ts,ptime,y);CHKERRQ(ierr);
4749   ierr = VecAXPY(y,-1.0,u);CHKERRQ(ierr);
4750   ierr = VecGetArrayRead(y,&yy);CHKERRQ(ierr);
4751 #if defined(PETSC_USE_COMPLEX)
4752   {
4753     PetscReal *yreal;
4754     PetscInt  i,n;
4755     ierr = VecGetLocalSize(y,&n);CHKERRQ(ierr);
4756     ierr = PetscMalloc(n*sizeof(PetscReal),&yreal);CHKERRQ(ierr);
4757     for (i=0; i<n; i++) yreal[i] = PetscRealPart(yy[i]);
4758     ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yreal);CHKERRQ(ierr);
4759     ierr = PetscFree(yreal);CHKERRQ(ierr);
4760   }
4761 #else
4762   ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yy);CHKERRQ(ierr);
4763 #endif
4764   ierr = VecRestoreArrayRead(y,&yy);CHKERRQ(ierr);
4765   ierr = VecDestroy(&y);CHKERRQ(ierr);
4766   if (((ctx->howoften > 0) && (!(step % ctx->howoften))) || ((ctx->howoften == -1) && ts->reason)) {
4767     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4768   }
4769   PetscFunctionReturn(0);
4770 }
4771 
4772 #undef __FUNCT__
4773 #define __FUNCT__ "TSMonitorLGSNESIterations"
4774 PetscErrorCode TSMonitorLGSNESIterations(TS ts,PetscInt n,PetscReal ptime,Vec v,void *monctx)
4775 {
4776   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
4777   PetscReal      x   = ptime,y;
4778   PetscErrorCode ierr;
4779   PetscInt       its;
4780 
4781   PetscFunctionBegin;
4782   if (!n) {
4783     PetscDrawAxis axis;
4784 
4785     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4786     ierr = PetscDrawAxisSetLabels(axis,"Nonlinear iterations as function of time","Time","SNES Iterations");CHKERRQ(ierr);
4787     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4788 
4789     ctx->snes_its = 0;
4790   }
4791   ierr = TSGetSNESIterations(ts,&its);CHKERRQ(ierr);
4792   y    = its - ctx->snes_its;
4793   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
4794   if (((ctx->howoften > 0) && (!(n % ctx->howoften)) && (n > -1)) || ((ctx->howoften == -1) && (n == -1))) {
4795     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4796   }
4797   ctx->snes_its = its;
4798   PetscFunctionReturn(0);
4799 }
4800 
4801 #undef __FUNCT__
4802 #define __FUNCT__ "TSMonitorLGKSPIterations"
4803 PetscErrorCode TSMonitorLGKSPIterations(TS ts,PetscInt n,PetscReal ptime,Vec v,void *monctx)
4804 {
4805   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
4806   PetscReal      x   = ptime,y;
4807   PetscErrorCode ierr;
4808   PetscInt       its;
4809 
4810   PetscFunctionBegin;
4811   if (!n) {
4812     PetscDrawAxis axis;
4813 
4814     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4815     ierr = PetscDrawAxisSetLabels(axis,"Linear iterations as function of time","Time","KSP Iterations");CHKERRQ(ierr);
4816     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4817 
4818     ctx->ksp_its = 0;
4819   }
4820   ierr = TSGetKSPIterations(ts,&its);CHKERRQ(ierr);
4821   y    = its - ctx->ksp_its;
4822   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
4823   if (((ctx->howoften > 0) && (!(n % ctx->howoften)) && (n > -1)) || ((ctx->howoften == -1) && (n == -1))) {
4824     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4825   }
4826   ctx->ksp_its = its;
4827   PetscFunctionReturn(0);
4828 }
4829 
4830 #undef __FUNCT__
4831 #define __FUNCT__ "TSComputeLinearStability"
4832 /*@
4833    TSComputeLinearStability - computes the linear stability function at a point
4834 
4835    Collective on TS and Vec
4836 
4837    Input Parameters:
4838 +  ts - the TS context
4839 -  xr,xi - real and imaginary part of input arguments
4840 
4841    Output Parameters:
4842 .  yr,yi - real and imaginary part of function value
4843 
4844    Level: developer
4845 
4846 .keywords: TS, compute
4847 
4848 .seealso: TSSetRHSFunction(), TSComputeIFunction()
4849 @*/
4850 PetscErrorCode TSComputeLinearStability(TS ts,PetscReal xr,PetscReal xi,PetscReal *yr,PetscReal *yi)
4851 {
4852   PetscErrorCode ierr;
4853 
4854   PetscFunctionBegin;
4855   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4856   if (!ts->ops->linearstability) SETERRQ(PetscObjectComm((PetscObject)ts),PETSC_ERR_SUP,"Linearized stability function not provided for this method");
4857   ierr = (*ts->ops->linearstability)(ts,xr,xi,yr,yi);CHKERRQ(ierr);
4858   PetscFunctionReturn(0);
4859 }
4860