xref: /petsc/src/ts/interface/ts.c (revision 4fb1bf5f03bcdb71885345f9db53d14221f74af2)
1 
2 #include <petsc-private/tsimpl.h>        /*I "petscts.h"  I*/
3 #include <petscdmshell.h>
4 
5 /* Logging support */
6 PetscClassId  TS_CLASSID, DMTS_CLASSID;
7 PetscLogEvent  TS_Step, TS_PseudoComputeTimeStep, TS_FunctionEval, TS_JacobianEval;
8 
9 const char *const TSExactFinalTimeOptions[] = {"STEPOVER","INTERPOLATE","MATCHSTEP","TSExactFinalTimeOption","TS_EXACTFINALTIME_",0};
10 
11 #undef __FUNCT__
12 #define __FUNCT__ "TSSetTypeFromOptions"
13 /*
14   TSSetTypeFromOptions - Sets the type of ts from user options.
15 
16   Collective on TS
17 
18   Input Parameter:
19 . ts - The ts
20 
21   Level: intermediate
22 
23 .keywords: TS, set, options, database, type
24 .seealso: TSSetFromOptions(), TSSetType()
25 */
26 static PetscErrorCode TSSetTypeFromOptions(TS ts)
27 {
28   PetscBool      opt;
29   const char     *defaultType;
30   char           typeName[256];
31   PetscErrorCode ierr;
32 
33   PetscFunctionBegin;
34   if (((PetscObject)ts)->type_name) {
35     defaultType = ((PetscObject)ts)->type_name;
36   } else {
37     defaultType = TSEULER;
38   }
39 
40   if (!TSRegisterAllCalled) {ierr = TSRegisterAll(PETSC_NULL);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 #undef __FUNCT__
51 #define __FUNCT__ "TSSetFromOptions"
52 /*@
53    TSSetFromOptions - Sets various TS parameters from user options.
54 
55    Collective on TS
56 
57    Input Parameter:
58 .  ts - the TS context obtained from TSCreate()
59 
60    Options Database Keys:
61 +  -ts_type <type> - TSEULER, TSBEULER, TSSUNDIALS, TSPSEUDO, TSCN, TSRK, TSTHETA, TSGL, TSSSP
62 .  -ts_max_steps maxsteps - maximum number of time-steps to take
63 .  -ts_final_time time - maximum time to compute to
64 .  -ts_dt dt - initial time step
65 .  -ts_monitor - print information at each timestep
66 .  -ts_monitor_lg_timestep - Monitor timestep size graphically
67 .  -ts_monitor_lg_solution - Monitor solution graphically
68 .  -ts_monitor_lg_error - Monitor error graphically
69 .  -ts_monitor_lg_snes_iterations - Monitor number nonlinear iterations for each timestep graphically
70 .  -ts_monitor_lg_ksp_iterations - Monitor number nonlinear iterations for each timestep graphically
71 .  -ts_monitor_sp_eig - Monitor eigenvalues of linearized operator graphically
72 .  -ts_monitor_draw_solution - Monitor solution graphically
73 .  -ts_monitor_draw_solution - Monitor solution graphically
74 .  -ts_monitor_draw_error - Monitor error graphically
75 .  -ts_monitor_draw_solution_binary <filename> - Save each solution to a binary file
76 -  -ts_monitor_draw_solution_vtk <filename.vts> - Save each time step to a binary file, use filename-%%03D.vts
77 
78    Level: beginner
79 
80 .keywords: TS, timestep, set, options, database
81 
82 .seealso: TSGetType()
83 @*/
84 PetscErrorCode  TSSetFromOptions(TS ts)
85 {
86   PetscBool      opt,flg;
87   PetscErrorCode ierr;
88   PetscViewer    monviewer;
89   char           monfilename[PETSC_MAX_PATH_LEN];
90   SNES           snes;
91   TSAdapt        adapt;
92   PetscReal      time_step;
93   TSExactFinalTimeOption      eftopt;
94 
95   PetscFunctionBegin;
96   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
97   ierr = PetscObjectOptionsBegin((PetscObject)ts);CHKERRQ(ierr);
98     /* Handle TS type options */
99     ierr = TSSetTypeFromOptions(ts);CHKERRQ(ierr);
100 
101     /* Handle generic TS options */
102     ierr = PetscOptionsInt("-ts_max_steps","Maximum number of time steps","TSSetDuration",ts->max_steps,&ts->max_steps,PETSC_NULL);CHKERRQ(ierr);
103     ierr = PetscOptionsReal("-ts_final_time","Time to run to","TSSetDuration",ts->max_time,&ts->max_time,PETSC_NULL);CHKERRQ(ierr);
104     ierr = PetscOptionsReal("-ts_init_time","Initial time","TSSetTime",ts->ptime,&ts->ptime,PETSC_NULL);CHKERRQ(ierr);
105     ierr = PetscOptionsReal("-ts_dt","Initial time step","TSSetTimeStep",ts->time_step,&time_step,&flg);CHKERRQ(ierr);
106     if (flg) {
107       ierr = TSSetTimeStep(ts,time_step);CHKERRQ(ierr);
108     }
109     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);
110     if (flg) {ierr = TSSetExactFinalTime(ts,eftopt);CHKERRQ(ierr);}
111     ierr = PetscOptionsInt("-ts_max_snes_failures","Maximum number of nonlinear solve failures","TSSetMaxSNESFailures",ts->max_snes_failures,&ts->max_snes_failures,PETSC_NULL);CHKERRQ(ierr);
112     ierr = PetscOptionsInt("-ts_max_reject","Maximum number of step rejections before step fails","TSSetMaxStepRejections",ts->max_reject,&ts->max_reject,PETSC_NULL);CHKERRQ(ierr);
113     ierr = PetscOptionsBool("-ts_error_if_step_fails","Error if no step succeeds","TSSetErrorIfStepFails",ts->errorifstepfailed,&ts->errorifstepfailed,PETSC_NULL);CHKERRQ(ierr);
114     ierr = PetscOptionsReal("-ts_rtol","Relative tolerance for local truncation error","TSSetTolerances",ts->rtol,&ts->rtol,PETSC_NULL);CHKERRQ(ierr);
115     ierr = PetscOptionsReal("-ts_atol","Absolute tolerance for local truncation error","TSSetTolerances",ts->atol,&ts->atol,PETSC_NULL);CHKERRQ(ierr);
116 
117     /* Monitor options */
118     ierr = PetscOptionsString("-ts_monitor","Monitor timestep size","TSMonitorDefault","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
119     if (flg) {
120       ierr = PetscViewerASCIIOpen(((PetscObject)ts)->comm,monfilename,&monviewer);CHKERRQ(ierr);
121       ierr = TSMonitorSet(ts,TSMonitorDefault,monviewer,(PetscErrorCode (*)(void**))PetscViewerDestroy);CHKERRQ(ierr);
122     }
123     ierr = PetscOptionsString("-ts_monitor_python","Use Python function","TSMonitorSet",0,monfilename,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
124     if (flg) {ierr = PetscPythonMonitorSet((PetscObject)ts,monfilename);CHKERRQ(ierr);}
125 
126     ierr = PetscOptionsName("-ts_monitor_lg_timestep","Monitor timestep size graphically","TSMonitorLGTimeStep",&opt);CHKERRQ(ierr);
127     if (opt) {
128       TSMonitorLGCtx ctx;
129       PetscInt       howoften = 1;
130 
131       ierr = PetscOptionsInt("-ts_monitor_lg_timestep","Monitor timestep size graphically","TSMonitorLGTimeStep",howoften,&howoften,PETSC_NULL);CHKERRQ(ierr);
132       ierr = TSMonitorLGCtxCreate(((PetscObject)ts)->comm,0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,howoften,&ctx);CHKERRQ(ierr);
133       ierr = TSMonitorSet(ts,TSMonitorLGTimeStep,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
134     }
135     ierr = PetscOptionsName("-ts_monitor_lg_solution","Monitor solution graphically","TSMonitorLGSolution",&opt);CHKERRQ(ierr);
136     if (opt) {
137       TSMonitorLGCtx ctx;
138       PetscInt       howoften = 1;
139 
140       ierr = PetscOptionsInt("-ts_monitor_lg_solution","Monitor solution graphically","TSMonitorLGSolution",howoften,&howoften,PETSC_NULL);CHKERRQ(ierr);
141       ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);
142       ierr = TSMonitorSet(ts,TSMonitorLGSolution,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
143     }
144     ierr = PetscOptionsName("-ts_monitor_lg_error","Monitor error graphically","TSMonitorLGError",&opt);CHKERRQ(ierr);
145     if (opt) {
146       TSMonitorLGCtx ctx;
147       PetscInt       howoften = 1;
148 
149       ierr = PetscOptionsInt("-ts_monitor_lg_error","Monitor error graphically","TSMonitorLGError",howoften,&howoften,PETSC_NULL);CHKERRQ(ierr);
150       ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);
151       ierr = TSMonitorSet(ts,TSMonitorLGError,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
152     }
153     ierr = PetscOptionsName("-ts_monitor_lg_snes_iterations","Monitor number nonlinear iterations for each timestep graphically","TSMonitorLGSNESIterations",&opt);CHKERRQ(ierr);
154     if (opt) {
155       TSMonitorLGCtx ctx;
156       PetscInt       howoften = 1;
157 
158       ierr = PetscOptionsInt("-ts_monitor_lg_snes_iterations","Monitor number nonlinear iterations for each timestep graphically","TSMonitorLGSNESIterations",howoften,&howoften,PETSC_NULL);CHKERRQ(ierr);
159       ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,howoften,&ctx);
160       ierr = TSMonitorSet(ts,TSMonitorLGSNESIterations,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
161     }
162     ierr = PetscOptionsName("-ts_monitor_lg_ksp_iterations","Monitor number nonlinear iterations for each timestep graphically","TSMonitorLGKSPIterations",&opt);CHKERRQ(ierr);
163     if (opt) {
164       TSMonitorLGCtx ctx;
165       PetscInt       howoften = 1;
166 
167       ierr = PetscOptionsInt("-ts_monitor_lg_ksp_iterations","Monitor number nonlinear iterations for each timestep graphically","TSMonitorLGKSPIterations",howoften,&howoften,PETSC_NULL);CHKERRQ(ierr);
168       ierr = TSMonitorLGCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,howoften,&ctx);
169       ierr = TSMonitorSet(ts,TSMonitorLGKSPIterations,ctx,(PetscErrorCode (*)(void**))TSMonitorLGCtxDestroy);CHKERRQ(ierr);
170     }
171     ierr = PetscOptionsName("-ts_monitor_sp_eig","Monitor eigenvalues of linearized operator graphically","TSMonitorSPEig",&opt);CHKERRQ(ierr);
172     if (opt) {
173       TSMonitorSPEigCtx ctx;
174       PetscInt          howoften = 1;
175 
176       ierr = PetscOptionsInt("-ts_monitor_sp_eig","Monitor eigenvalues of linearized operator graphically","TSMonitorSPEig",howoften,&howoften,PETSC_NULL);CHKERRQ(ierr);
177       ierr = TSMonitorSPEigCtxCreate(PETSC_COMM_SELF,0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);
178       ierr = TSMonitorSet(ts,TSMonitorSPEig,ctx,(PetscErrorCode (*)(void**))TSMonitorSPEigCtxDestroy);CHKERRQ(ierr);
179     }
180     opt  = PETSC_FALSE;
181     ierr = PetscOptionsName("-ts_monitor_draw_solution","Monitor solution graphically","TSMonitorDrawSolution",&opt);CHKERRQ(ierr);
182     if (opt) {
183       TSMonitorDrawCtx ctx;
184       PetscInt         howoften = 1;
185 
186       ierr = PetscOptionsInt("-ts_monitor_draw_solution","Monitor solution graphically","TSMonitorDrawSolution",howoften,&howoften,PETSC_NULL);CHKERRQ(ierr);
187       ierr = TSMonitorDrawCtxCreate(((PetscObject)ts)->comm,0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);
188       ierr = TSMonitorSet(ts,TSMonitorDrawSolution,ctx,(PetscErrorCode (*)(void**))TSMonitorDrawCtxDestroy);CHKERRQ(ierr);
189     }
190     opt  = PETSC_FALSE;
191     ierr = PetscOptionsName("-ts_monitor_draw_error","Monitor error graphically","TSMonitorDrawError",&opt);CHKERRQ(ierr);
192     if (opt) {
193       TSMonitorDrawCtx ctx;
194       PetscInt         howoften = 1;
195 
196       ierr = PetscOptionsInt("-ts_monitor_draw_error","Monitor error graphically","TSMonitorDrawError",howoften,&howoften,PETSC_NULL);CHKERRQ(ierr);
197       ierr = TSMonitorDrawCtxCreate(((PetscObject)ts)->comm,0,0,PETSC_DECIDE,PETSC_DECIDE,600,400,howoften,&ctx);
198       ierr = TSMonitorSet(ts,TSMonitorDrawError,ctx,(PetscErrorCode (*)(void**))TSMonitorDrawCtxDestroy);CHKERRQ(ierr);
199     }
200     opt  = PETSC_FALSE;
201     ierr = PetscOptionsString("-ts_monitor_draw_solution_binary","Save each solution to a binary file","TSMonitorSolutionBinary",0,monfilename,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
202     if (flg) {
203       PetscViewer ctx;
204       if (monfilename[0]) {
205         ierr = PetscViewerBinaryOpen(((PetscObject)ts)->comm,monfilename,FILE_MODE_WRITE,&ctx);CHKERRQ(ierr);
206       } else {
207         ctx = PETSC_VIEWER_BINARY_(((PetscObject)ts)->comm);
208       }
209       ierr = TSMonitorSet(ts,TSMonitorSolutionBinary,ctx,(PetscErrorCode (*)(void**))PetscViewerDestroy);CHKERRQ(ierr);
210     }
211     opt  = PETSC_FALSE;
212     ierr = PetscOptionsString("-ts_monitor_draw_solution_vtk","Save each time step to a binary file, use filename-%%03D.vts","TSMonitorSolutionVTK",0,monfilename,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
213     if (flg) {
214       const char *ptr,*ptr2;
215       char *filetemplate;
216       if (!monfilename[0]) SETERRQ(((PetscObject)ts)->comm,PETSC_ERR_USER,"-ts_monitor_draw_solution_vtk requires a file template, e.g. filename-%%03D.vts");
217       /* Do some cursory validation of the input. */
218       ierr = PetscStrstr(monfilename,"%",(char**)&ptr);CHKERRQ(ierr);
219       if (!ptr) SETERRQ(((PetscObject)ts)->comm,PETSC_ERR_USER,"-ts_monitor_draw_solution_vtk requires a file template, e.g. filename-%%03D.vts");
220       for (ptr++ ; ptr && *ptr; ptr++) {
221         ierr = PetscStrchr("DdiouxX",*ptr,(char**)&ptr2);CHKERRQ(ierr);
222         if (!ptr2 && (*ptr < '0' || '9' < *ptr)) SETERRQ(((PetscObject)ts)->comm,PETSC_ERR_USER,"Invalid file template argument to -ts_monitor_draw_solution_vtk, should look like filename-%%03D.vts");
223         if (ptr2) break;
224       }
225       ierr = PetscStrallocpy(monfilename,&filetemplate);CHKERRQ(ierr);
226       ierr = TSMonitorSet(ts,TSMonitorSolutionVTK,filetemplate,(PetscErrorCode (*)(void**))TSMonitorSolutionVTKDestroy);CHKERRQ(ierr);
227     }
228 
229     ierr = TSGetTSAdapt(ts,&adapt);CHKERRQ(ierr);
230     ierr = TSAdaptSetFromOptions(adapt);CHKERRQ(ierr);
231 
232     ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
233     if (ts->problem_type == TS_LINEAR) {ierr = SNESSetType(snes,SNESKSPONLY);CHKERRQ(ierr);}
234 
235     /* Handle specific TS options */
236     if (ts->ops->setfromoptions) {
237       ierr = (*ts->ops->setfromoptions)(ts);CHKERRQ(ierr);
238     }
239 
240     /* process any options handlers added with PetscObjectAddOptionsHandler() */
241     ierr = PetscObjectProcessOptionsHandlers((PetscObject)ts);CHKERRQ(ierr);
242   ierr = PetscOptionsEnd();CHKERRQ(ierr);
243   PetscFunctionReturn(0);
244 }
245 
246 #undef __FUNCT__
247 #undef __FUNCT__
248 #define __FUNCT__ "TSComputeRHSJacobian"
249 /*@
250    TSComputeRHSJacobian - Computes the Jacobian matrix that has been
251       set with TSSetRHSJacobian().
252 
253    Collective on TS and Vec
254 
255    Input Parameters:
256 +  ts - the TS context
257 .  t - current timestep
258 -  U - input vector
259 
260    Output Parameters:
261 +  A - Jacobian matrix
262 .  B - optional preconditioning matrix
263 -  flag - flag indicating matrix structure
264 
265    Notes:
266    Most users should not need to explicitly call this routine, as it
267    is used internally within the nonlinear solvers.
268 
269    See KSPSetOperators() for important information about setting the
270    flag parameter.
271 
272    Level: developer
273 
274 .keywords: SNES, compute, Jacobian, matrix
275 
276 .seealso:  TSSetRHSJacobian(), KSPSetOperators()
277 @*/
278 PetscErrorCode  TSComputeRHSJacobian(TS ts,PetscReal t,Vec U,Mat *A,Mat *B,MatStructure *flg)
279 {
280   PetscErrorCode ierr;
281   PetscInt       Ustate;
282   DM             dm;
283   DMTS           tsdm;
284   TSRHSJacobian  rhsjacobianfunc;
285   void           *ctx;
286   TSIJacobian    ijacobianfunc;
287 
288   PetscFunctionBegin;
289   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
290   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
291   PetscCheckSameComm(ts,1,U,3);
292   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
293   ierr = DMGetDMTS(dm,&tsdm);CHKERRQ(ierr);
294   ierr = DMTSGetRHSJacobian(dm,&rhsjacobianfunc,&ctx);CHKERRQ(ierr);
295   ierr = DMTSGetIJacobian(dm,&ijacobianfunc,PETSC_NULL);CHKERRQ(ierr);
296   ierr = PetscObjectStateQuery((PetscObject)U,&Ustate);CHKERRQ(ierr);
297   if (ts->rhsjacobian.time == t && (ts->problem_type == TS_LINEAR || (ts->rhsjacobian.X == U && ts->rhsjacobian.Xstate == Ustate))) {
298     *flg = ts->rhsjacobian.mstructure;
299     PetscFunctionReturn(0);
300   }
301 
302   if (!rhsjacobianfunc && !ijacobianfunc) SETERRQ(((PetscObject)ts)->comm,PETSC_ERR_USER,"Must call TSSetRHSJacobian() and / or TSSetIJacobian()");
303 
304   if (rhsjacobianfunc) {
305     ierr = PetscLogEventBegin(TS_JacobianEval,ts,U,*A,*B);CHKERRQ(ierr);
306     *flg = DIFFERENT_NONZERO_PATTERN;
307     PetscStackPush("TS user Jacobian function");
308     ierr = (*rhsjacobianfunc)(ts,t,U,A,B,flg,ctx);CHKERRQ(ierr);
309     PetscStackPop;
310     ierr = PetscLogEventEnd(TS_JacobianEval,ts,U,*A,*B);CHKERRQ(ierr);
311     /* make sure user returned a correct Jacobian and preconditioner */
312     PetscValidHeaderSpecific(*A,MAT_CLASSID,4);
313     PetscValidHeaderSpecific(*B,MAT_CLASSID,5);
314   } else {
315     ierr = MatZeroEntries(*A);CHKERRQ(ierr);
316     if (*A != *B) {ierr = MatZeroEntries(*B);CHKERRQ(ierr);}
317     *flg = SAME_NONZERO_PATTERN;
318   }
319   ts->rhsjacobian.time = t;
320   ts->rhsjacobian.X = U;
321   ierr = PetscObjectStateQuery((PetscObject)U,&ts->rhsjacobian.Xstate);CHKERRQ(ierr);
322   ts->rhsjacobian.mstructure = *flg;
323   PetscFunctionReturn(0);
324 }
325 
326 #undef __FUNCT__
327 #define __FUNCT__ "TSComputeRHSFunction"
328 /*@
329    TSComputeRHSFunction - Evaluates the right-hand-side function.
330 
331    Collective on TS and Vec
332 
333    Input Parameters:
334 +  ts - the TS context
335 .  t - current time
336 -  U - state vector
337 
338    Output Parameter:
339 .  y - right hand side
340 
341    Note:
342    Most users should not need to explicitly call this routine, as it
343    is used internally within the nonlinear solvers.
344 
345    Level: developer
346 
347 .keywords: TS, compute
348 
349 .seealso: TSSetRHSFunction(), TSComputeIFunction()
350 @*/
351 PetscErrorCode TSComputeRHSFunction(TS ts,PetscReal t,Vec U,Vec y)
352 {
353   PetscErrorCode ierr;
354   TSRHSFunction  rhsfunction;
355   TSIFunction    ifunction;
356   void           *ctx;
357   DM             dm;
358 
359   PetscFunctionBegin;
360   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
361   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
362   PetscValidHeaderSpecific(y,VEC_CLASSID,4);
363   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
364   ierr = DMTSGetRHSFunction(dm,&rhsfunction,&ctx);CHKERRQ(ierr);
365   ierr = DMTSGetIFunction(dm,&ifunction,PETSC_NULL);CHKERRQ(ierr);
366 
367   if (!rhsfunction && !ifunction) SETERRQ(((PetscObject)ts)->comm,PETSC_ERR_USER,"Must call TSSetRHSFunction() and / or TSSetIFunction()");
368 
369   ierr = PetscLogEventBegin(TS_FunctionEval,ts,U,y,0);CHKERRQ(ierr);
370   if (rhsfunction) {
371     PetscStackPush("TS user right-hand-side function");
372     ierr = (*rhsfunction)(ts,t,U,y,ctx);CHKERRQ(ierr);
373     PetscStackPop;
374   } else {
375     ierr = VecZeroEntries(y);CHKERRQ(ierr);
376   }
377 
378   ierr = PetscLogEventEnd(TS_FunctionEval,ts,U,y,0);CHKERRQ(ierr);
379   PetscFunctionReturn(0);
380 }
381 
382 #undef __FUNCT__
383 #define __FUNCT__ "TSComputeSolutionFunction"
384 /*@
385    TSComputeSolutionFunction - Evaluates the solution function.
386 
387    Collective on TS and Vec
388 
389    Input Parameters:
390 +  ts - the TS context
391 -  t - current time
392 
393    Output Parameter:
394 .  U - the solution
395 
396    Note:
397    Most users should not need to explicitly call this routine, as it
398    is used internally within the nonlinear solvers.
399 
400    Level: developer
401 
402 .keywords: TS, compute
403 
404 .seealso: TSSetSolutionFunction(), TSSetRHSFunction(), TSComputeIFunction()
405 @*/
406 PetscErrorCode TSComputeSolutionFunction(TS ts,PetscReal t,Vec U)
407 {
408   PetscErrorCode     ierr;
409   TSSolutionFunction solutionfunction;
410   void               *ctx;
411   DM                 dm;
412 
413   PetscFunctionBegin;
414   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
415   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
416   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
417   ierr = DMTSGetSolutionFunction(dm,&solutionfunction,&ctx);CHKERRQ(ierr);
418 
419   if (solutionfunction) {
420     PetscStackPush("TS user right-hand-side function");
421     ierr = (*solutionfunction)(ts,t,U,ctx);CHKERRQ(ierr);
422     PetscStackPop;
423   }
424   PetscFunctionReturn(0);
425 }
426 
427 #undef __FUNCT__
428 #define __FUNCT__ "TSGetRHSVec_Private"
429 static PetscErrorCode TSGetRHSVec_Private(TS ts,Vec *Frhs)
430 {
431   Vec            F;
432   PetscErrorCode ierr;
433 
434   PetscFunctionBegin;
435   *Frhs = PETSC_NULL;
436   ierr = TSGetIFunction(ts,&F,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
437   if (!ts->Frhs) {
438     ierr = VecDuplicate(F,&ts->Frhs);CHKERRQ(ierr);
439   }
440   *Frhs = ts->Frhs;
441   PetscFunctionReturn(0);
442 }
443 
444 #undef __FUNCT__
445 #define __FUNCT__ "TSGetRHSMats_Private"
446 static PetscErrorCode TSGetRHSMats_Private(TS ts,Mat *Arhs,Mat *Brhs)
447 {
448   Mat            A,B;
449   PetscErrorCode ierr;
450 
451   PetscFunctionBegin;
452   ierr = TSGetIJacobian(ts,&A,&B,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
453   if (Arhs) {
454     if (!ts->Arhs) {
455       ierr = MatDuplicate(A,MAT_DO_NOT_COPY_VALUES,&ts->Arhs);CHKERRQ(ierr);
456     }
457     *Arhs = ts->Arhs;
458   }
459   if (Brhs) {
460     if (!ts->Brhs) {
461       ierr = MatDuplicate(B,MAT_DO_NOT_COPY_VALUES,&ts->Brhs);CHKERRQ(ierr);
462     }
463     *Brhs = ts->Brhs;
464   }
465   PetscFunctionReturn(0);
466 }
467 
468 #undef __FUNCT__
469 #define __FUNCT__ "TSComputeIFunction"
470 /*@
471    TSComputeIFunction - Evaluates the DAE residual written in implicit form F(t,U,Udot)=0
472 
473    Collective on TS and Vec
474 
475    Input Parameters:
476 +  ts - the TS context
477 .  t - current time
478 .  U - state vector
479 .  Udot - time derivative of state vector
480 -  imex - flag indicates if the method is IMEX so that the RHSFunction should be kept separate
481 
482    Output Parameter:
483 .  Y - right hand side
484 
485    Note:
486    Most users should not need to explicitly call this routine, as it
487    is used internally within the nonlinear solvers.
488 
489    If the user did did not write their equations in implicit form, this
490    function recasts them in implicit form.
491 
492    Level: developer
493 
494 .keywords: TS, compute
495 
496 .seealso: TSSetIFunction(), TSComputeRHSFunction()
497 @*/
498 PetscErrorCode TSComputeIFunction(TS ts,PetscReal t,Vec U,Vec Udot,Vec Y,PetscBool imex)
499 {
500   PetscErrorCode ierr;
501   TSIFunction    ifunction;
502   TSRHSFunction  rhsfunction;
503   void           *ctx;
504   DM             dm;
505 
506   PetscFunctionBegin;
507   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
508   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
509   PetscValidHeaderSpecific(Udot,VEC_CLASSID,4);
510   PetscValidHeaderSpecific(Y,VEC_CLASSID,5);
511 
512   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
513   ierr = DMTSGetIFunction(dm,&ifunction,&ctx);CHKERRQ(ierr);
514   ierr = DMTSGetRHSFunction(dm,&rhsfunction,PETSC_NULL);CHKERRQ(ierr);
515 
516   if (!rhsfunction && !ifunction) SETERRQ(((PetscObject)ts)->comm,PETSC_ERR_USER,"Must call TSSetRHSFunction() and / or TSSetIFunction()");
517 
518   ierr = PetscLogEventBegin(TS_FunctionEval,ts,U,Udot,Y);CHKERRQ(ierr);
519   if (ifunction) {
520     PetscStackPush("TS user implicit function");
521     ierr = (*ifunction)(ts,t,U,Udot,Y,ctx);CHKERRQ(ierr);
522     PetscStackPop;
523   }
524   if (imex) {
525     if (!ifunction) {
526       ierr = VecCopy(Udot,Y);CHKERRQ(ierr);
527     }
528   } else if (rhsfunction) {
529     if (ifunction) {
530       Vec Frhs;
531       ierr = TSGetRHSVec_Private(ts,&Frhs);CHKERRQ(ierr);
532       ierr = TSComputeRHSFunction(ts,t,U,Frhs);CHKERRQ(ierr);
533       ierr = VecAXPY(Y,-1,Frhs);CHKERRQ(ierr);
534     } else {
535       ierr = TSComputeRHSFunction(ts,t,U,Y);CHKERRQ(ierr);
536       ierr = VecAYPX(Y,-1,Udot);CHKERRQ(ierr);
537     }
538   }
539   ierr = PetscLogEventEnd(TS_FunctionEval,ts,U,Udot,Y);CHKERRQ(ierr);
540   PetscFunctionReturn(0);
541 }
542 
543 #undef __FUNCT__
544 #define __FUNCT__ "TSComputeIJacobian"
545 /*@
546    TSComputeIJacobian - Evaluates the Jacobian of the DAE
547 
548    Collective on TS and Vec
549 
550    Input
551       Input Parameters:
552 +  ts - the TS context
553 .  t - current timestep
554 .  U - state vector
555 .  Udot - time derivative of state vector
556 .  shift - shift to apply, see note below
557 -  imex - flag indicates if the method is IMEX so that the RHSJacobian should be kept separate
558 
559    Output Parameters:
560 +  A - Jacobian matrix
561 .  B - optional preconditioning matrix
562 -  flag - flag indicating matrix structure
563 
564    Notes:
565    If F(t,U,Udot)=0 is the DAE, the required Jacobian is
566 
567    dF/dU + shift*dF/dUdot
568 
569    Most users should not need to explicitly call this routine, as it
570    is used internally within the nonlinear solvers.
571 
572    Level: developer
573 
574 .keywords: TS, compute, Jacobian, matrix
575 
576 .seealso:  TSSetIJacobian()
577 @*/
578 PetscErrorCode TSComputeIJacobian(TS ts,PetscReal t,Vec U,Vec Udot,PetscReal shift,Mat *A,Mat *B,MatStructure *flg,PetscBool imex)
579 {
580   PetscInt       Ustate, Udotstate;
581   PetscErrorCode ierr;
582   TSIJacobian    ijacobian;
583   TSRHSJacobian  rhsjacobian;
584   DM             dm;
585   void           *ctx;
586 
587   PetscFunctionBegin;
588 
589   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
590   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
591   PetscValidHeaderSpecific(Udot,VEC_CLASSID,4);
592   PetscValidPointer(A,6);
593   PetscValidHeaderSpecific(*A,MAT_CLASSID,6);
594   PetscValidPointer(B,7);
595   PetscValidHeaderSpecific(*B,MAT_CLASSID,7);
596   PetscValidPointer(flg,8);
597 
598   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
599   ierr = DMTSGetIJacobian(dm,&ijacobian,&ctx);CHKERRQ(ierr);
600   ierr = DMTSGetRHSJacobian(dm,&rhsjacobian,PETSC_NULL);CHKERRQ(ierr);
601 
602   ierr = PetscObjectStateQuery((PetscObject)U,&Ustate);CHKERRQ(ierr);
603   ierr = PetscObjectStateQuery((PetscObject)Udot,&Udotstate);CHKERRQ(ierr);
604   if (ts->ijacobian.time == t && (ts->problem_type == TS_LINEAR || (ts->ijacobian.X == U && ts->ijacobian.Xstate == Ustate && ts->ijacobian.Xdot == Udot && ts->ijacobian.Xdotstate == Udotstate && ts->ijacobian.imex == imex))) {
605     *flg = ts->ijacobian.mstructure;
606     ierr = MatScale(*A, shift / ts->ijacobian.shift);CHKERRQ(ierr);
607     PetscFunctionReturn(0);
608   }
609 
610   if (!rhsjacobian && !ijacobian) SETERRQ(((PetscObject)ts)->comm,PETSC_ERR_USER,"Must call TSSetRHSJacobian() and / or TSSetIJacobian()");
611 
612   *flg = SAME_NONZERO_PATTERN;  /* In case we're solving a linear problem in which case it wouldn't get initialized below. */
613   ierr = PetscLogEventBegin(TS_JacobianEval,ts,U,*A,*B);CHKERRQ(ierr);
614   if (ijacobian) {
615     *flg = DIFFERENT_NONZERO_PATTERN;
616     PetscStackPush("TS user implicit Jacobian");
617     ierr = (*ijacobian)(ts,t,U,Udot,shift,A,B,flg,ctx);CHKERRQ(ierr);
618     PetscStackPop;
619     /* make sure user returned a correct Jacobian and preconditioner */
620     PetscValidHeaderSpecific(*A,MAT_CLASSID,4);
621     PetscValidHeaderSpecific(*B,MAT_CLASSID,5);
622   }
623   if (imex) {
624     if (!ijacobian) {  /* system was written as Udot = G(t,U) */
625       ierr = MatZeroEntries(*A);CHKERRQ(ierr);
626       ierr = MatShift(*A,shift);CHKERRQ(ierr);
627       if (*A != *B) {
628         ierr = MatZeroEntries(*B);CHKERRQ(ierr);
629         ierr = MatShift(*B,shift);CHKERRQ(ierr);
630       }
631       *flg = SAME_PRECONDITIONER;
632     }
633   } else {
634     if (!ijacobian) {
635       ierr = TSComputeRHSJacobian(ts,t,U,A,B,flg);CHKERRQ(ierr);
636       ierr = MatScale(*A,-1);CHKERRQ(ierr);
637       ierr = MatShift(*A,shift);CHKERRQ(ierr);
638       if (*A != *B) {
639         ierr = MatScale(*B,-1);CHKERRQ(ierr);
640         ierr = MatShift(*B,shift);CHKERRQ(ierr);
641       }
642     } else if (rhsjacobian) {
643       Mat Arhs,Brhs;
644       MatStructure axpy,flg2 = DIFFERENT_NONZERO_PATTERN;
645       ierr = TSGetRHSMats_Private(ts,&Arhs,&Brhs);CHKERRQ(ierr);
646       ierr = TSComputeRHSJacobian(ts,t,U,&Arhs,&Brhs,&flg2);CHKERRQ(ierr);
647       axpy = (*flg == flg2) ? SAME_NONZERO_PATTERN : DIFFERENT_NONZERO_PATTERN;
648       ierr = MatAXPY(*A,-1,Arhs,axpy);CHKERRQ(ierr);
649       if (*A != *B) {
650         ierr = MatAXPY(*B,-1,Brhs,axpy);CHKERRQ(ierr);
651       }
652       *flg = PetscMin(*flg,flg2);
653     }
654   }
655 
656   ts->ijacobian.time = t;
657   ts->ijacobian.X = U;
658   ts->ijacobian.Xdot = Udot;
659   ierr = PetscObjectStateQuery((PetscObject)U,&ts->ijacobian.Xstate);CHKERRQ(ierr);
660   ierr = PetscObjectStateQuery((PetscObject)Udot,&ts->ijacobian.Xdotstate);CHKERRQ(ierr);
661   ts->ijacobian.shift = shift;
662   ts->ijacobian.imex = imex;
663   ts->ijacobian.mstructure = *flg;
664   ierr = PetscLogEventEnd(TS_JacobianEval,ts,U,*A,*B);CHKERRQ(ierr);
665   PetscFunctionReturn(0);
666 }
667 
668 #undef __FUNCT__
669 #define __FUNCT__ "TSSetRHSFunction"
670 /*@C
671     TSSetRHSFunction - Sets the routine for evaluating the function,
672     where U_t = G(t,u).
673 
674     Logically Collective on TS
675 
676     Input Parameters:
677 +   ts - the TS context obtained from TSCreate()
678 .   r - vector to put the computed right hand side (or PETSC_NULL to have it created)
679 .   f - routine for evaluating the right-hand-side function
680 -   ctx - [optional] user-defined context for private data for the
681           function evaluation routine (may be PETSC_NULL)
682 
683     Calling sequence of func:
684 $     func (TS ts,PetscReal t,Vec u,Vec F,void *ctx);
685 
686 +   t - current timestep
687 .   u - input vector
688 .   F - function vector
689 -   ctx - [optional] user-defined function context
690 
691     Level: beginner
692 
693 .keywords: TS, timestep, set, right-hand-side, function
694 
695 .seealso: TSSetRHSJacobian(), TSSetIJacobian()
696 @*/
697 PetscErrorCode  TSSetRHSFunction(TS ts,Vec r,PetscErrorCode (*f)(TS,PetscReal,Vec,Vec,void*),void *ctx)
698 {
699   PetscErrorCode ierr;
700   SNES           snes;
701   Vec            ralloc = PETSC_NULL;
702   DM             dm;
703 
704   PetscFunctionBegin;
705   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
706   if (r) PetscValidHeaderSpecific(r,VEC_CLASSID,2);
707 
708   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
709   ierr = DMTSSetRHSFunction(dm,f,ctx);CHKERRQ(ierr);
710   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
711   if (!r && !ts->dm && ts->vec_sol) {
712     ierr = VecDuplicate(ts->vec_sol,&ralloc);CHKERRQ(ierr);
713     r = ralloc;
714   }
715   ierr = SNESSetFunction(snes,r,SNESTSFormFunction,ts);CHKERRQ(ierr);
716   ierr = VecDestroy(&ralloc);CHKERRQ(ierr);
717   PetscFunctionReturn(0);
718 }
719 
720 #undef __FUNCT__
721 #define __FUNCT__ "TSSetSolutionFunction"
722 /*@C
723     TSSetSolutionFunction - Provide a function that computes the solution of the ODE or DAE
724 
725     Logically Collective on TS
726 
727     Input Parameters:
728 +   ts - the TS context obtained from TSCreate()
729 .   f - routine for evaluating the solution
730 -   ctx - [optional] user-defined context for private data for the
731           function evaluation routine (may be PETSC_NULL)
732 
733     Calling sequence of func:
734 $     func (TS ts,PetscReal t,Vec u,void *ctx);
735 
736 +   t - current timestep
737 .   u - output vector
738 -   ctx - [optional] user-defined function context
739 
740     Notes:
741     This routine is used for testing accuracy of time integration schemes when you already know the solution.
742     If analytic solutions are not known for your system, consider using the Method of Manufactured Solutions to
743     create closed-form solutions with non-physical forcing terms.
744 
745     For low-dimensional problems solved in serial, such as small discrete systems, TSMonitorLGError() can be used to monitor the error history.
746 
747     Level: beginner
748 
749 .keywords: TS, timestep, set, right-hand-side, function
750 
751 .seealso: TSSetRHSJacobian(), TSSetIJacobian(), TSComputeSolutionFunction()
752 @*/
753 PetscErrorCode  TSSetSolutionFunction(TS ts,PetscErrorCode (*f)(TS,PetscReal,Vec,void*),void *ctx)
754 {
755   PetscErrorCode ierr;
756   DM             dm;
757 
758   PetscFunctionBegin;
759   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
760   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
761   ierr = DMTSSetSolutionFunction(dm,f,ctx);CHKERRQ(ierr);
762   PetscFunctionReturn(0);
763 }
764 
765 #undef __FUNCT__
766 #define __FUNCT__ "TSSetRHSJacobian"
767 /*@C
768    TSSetRHSJacobian - Sets the function to compute the Jacobian of F,
769    where U_t = G(U,t), as well as the location to store the matrix.
770 
771    Logically Collective on TS
772 
773    Input Parameters:
774 +  ts  - the TS context obtained from TSCreate()
775 .  A   - Jacobian matrix
776 .  B   - preconditioner matrix (usually same as A)
777 .  f   - the Jacobian evaluation routine
778 -  ctx - [optional] user-defined context for private data for the
779          Jacobian evaluation routine (may be PETSC_NULL)
780 
781    Calling sequence of func:
782 $     func (TS ts,PetscReal t,Vec u,Mat *A,Mat *B,MatStructure *flag,void *ctx);
783 
784 +  t - current timestep
785 .  u - input vector
786 .  A - matrix A, where U_t = A(t)u
787 .  B - preconditioner matrix, usually the same as A
788 .  flag - flag indicating information about the preconditioner matrix
789           structure (same as flag in KSPSetOperators())
790 -  ctx - [optional] user-defined context for matrix evaluation routine
791 
792    Notes:
793    See KSPSetOperators() for important information about setting the flag
794    output parameter in the routine func().  Be sure to read this information!
795 
796    The routine func() takes Mat * as the matrix arguments rather than Mat.
797    This allows the matrix evaluation routine to replace A and/or B with a
798    completely new matrix structure (not just different matrix elements)
799    when appropriate, for instance, if the nonzero structure is changing
800    throughout the global iterations.
801 
802    Level: beginner
803 
804 .keywords: TS, timestep, set, right-hand-side, Jacobian
805 
806 .seealso: SNESDefaultComputeJacobianColor(), TSSetRHSFunction()
807 
808 @*/
809 PetscErrorCode  TSSetRHSJacobian(TS ts,Mat A,Mat B,TSRHSJacobian f,void *ctx)
810 {
811   PetscErrorCode ierr;
812   SNES           snes;
813   DM             dm;
814   TSIJacobian    ijacobian;
815 
816   PetscFunctionBegin;
817   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
818   if (A) PetscValidHeaderSpecific(A,MAT_CLASSID,2);
819   if (B) PetscValidHeaderSpecific(B,MAT_CLASSID,3);
820   if (A) PetscCheckSameComm(ts,1,A,2);
821   if (B) PetscCheckSameComm(ts,1,B,3);
822 
823   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
824   ierr = DMTSSetRHSJacobian(dm,f,ctx);CHKERRQ(ierr);
825   ierr = DMTSGetIJacobian(dm,&ijacobian,PETSC_NULL);CHKERRQ(ierr);
826 
827   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
828   if (!ijacobian) {
829     ierr = SNESSetJacobian(snes,A,B,SNESTSFormJacobian,ts);CHKERRQ(ierr);
830   }
831   if (A) {
832     ierr = PetscObjectReference((PetscObject)A);CHKERRQ(ierr);
833     ierr = MatDestroy(&ts->Arhs);CHKERRQ(ierr);
834     ts->Arhs = A;
835   }
836   if (B) {
837     ierr = PetscObjectReference((PetscObject)B);CHKERRQ(ierr);
838     ierr = MatDestroy(&ts->Brhs);CHKERRQ(ierr);
839     ts->Brhs = B;
840   }
841   PetscFunctionReturn(0);
842 }
843 
844 
845 #undef __FUNCT__
846 #define __FUNCT__ "TSSetIFunction"
847 /*@C
848    TSSetIFunction - Set the function to compute F(t,U,U_t) where F() = 0 is the DAE to be solved.
849 
850    Logically Collective on TS
851 
852    Input Parameters:
853 +  ts  - the TS context obtained from TSCreate()
854 .  r   - vector to hold the residual (or PETSC_NULL to have it created internally)
855 .  f   - the function evaluation routine
856 -  ctx - user-defined context for private data for the function evaluation routine (may be PETSC_NULL)
857 
858    Calling sequence of f:
859 $  f(TS ts,PetscReal t,Vec u,Vec u_t,Vec F,ctx);
860 
861 +  t   - time at step/stage being solved
862 .  u   - state vector
863 .  u_t - time derivative of state vector
864 .  F   - function vector
865 -  ctx - [optional] user-defined context for matrix evaluation routine
866 
867    Important:
868    The user MUST call either this routine, TSSetRHSFunction().  This routine must be used when not solving an ODE, for example a DAE.
869 
870    Level: beginner
871 
872 .keywords: TS, timestep, set, DAE, Jacobian
873 
874 .seealso: TSSetRHSJacobian(), TSSetRHSFunction(), TSSetIJacobian()
875 @*/
876 PetscErrorCode  TSSetIFunction(TS ts,Vec res,TSIFunction f,void *ctx)
877 {
878   PetscErrorCode ierr;
879   SNES           snes;
880   Vec            resalloc = PETSC_NULL;
881   DM             dm;
882 
883   PetscFunctionBegin;
884   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
885   if (res) PetscValidHeaderSpecific(res,VEC_CLASSID,2);
886 
887   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
888   ierr = DMTSSetIFunction(dm,f,ctx);CHKERRQ(ierr);
889 
890   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
891   if (!res && !ts->dm && ts->vec_sol) {
892     ierr = VecDuplicate(ts->vec_sol,&resalloc);CHKERRQ(ierr);
893     res = resalloc;
894   }
895   ierr = SNESSetFunction(snes,res,SNESTSFormFunction,ts);CHKERRQ(ierr);
896   ierr = VecDestroy(&resalloc);CHKERRQ(ierr);
897 
898   PetscFunctionReturn(0);
899 }
900 
901 #undef __FUNCT__
902 #define __FUNCT__ "TSGetIFunction"
903 /*@C
904    TSGetIFunction - Returns the vector where the implicit residual is stored and the function/contex to compute it.
905 
906    Not Collective
907 
908    Input Parameter:
909 .  ts - the TS context
910 
911    Output Parameter:
912 +  r - vector to hold residual (or PETSC_NULL)
913 .  func - the function to compute residual (or PETSC_NULL)
914 -  ctx - the function context (or PETSC_NULL)
915 
916    Level: advanced
917 
918 .keywords: TS, nonlinear, get, function
919 
920 .seealso: TSSetIFunction(), SNESGetFunction()
921 @*/
922 PetscErrorCode TSGetIFunction(TS ts,Vec *r,TSIFunction *func,void **ctx)
923 {
924   PetscErrorCode ierr;
925   SNES           snes;
926   DM             dm;
927 
928   PetscFunctionBegin;
929   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
930   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
931   ierr = SNESGetFunction(snes,r,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
932   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
933   ierr = DMTSGetIFunction(dm,func,ctx);CHKERRQ(ierr);
934   PetscFunctionReturn(0);
935 }
936 
937 #undef __FUNCT__
938 #define __FUNCT__ "TSGetRHSFunction"
939 /*@C
940    TSGetRHSFunction - Returns the vector where the right hand side is stored and the function/context to compute it.
941 
942    Not Collective
943 
944    Input Parameter:
945 .  ts - the TS context
946 
947    Output Parameter:
948 +  r - vector to hold computed right hand side (or PETSC_NULL)
949 .  func - the function to compute right hand side (or PETSC_NULL)
950 -  ctx - the function context (or PETSC_NULL)
951 
952    Level: advanced
953 
954 .keywords: TS, nonlinear, get, function
955 
956 .seealso: TSSetRhsfunction(), SNESGetFunction()
957 @*/
958 PetscErrorCode TSGetRHSFunction(TS ts,Vec *r,TSRHSFunction *func,void **ctx)
959 {
960   PetscErrorCode ierr;
961   SNES           snes;
962   DM             dm;
963 
964   PetscFunctionBegin;
965   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
966   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
967   ierr = SNESGetFunction(snes,r,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
968   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
969   ierr = DMTSGetRHSFunction(dm,func,ctx);CHKERRQ(ierr);
970   PetscFunctionReturn(0);
971 }
972 
973 #undef __FUNCT__
974 #define __FUNCT__ "TSSetIJacobian"
975 /*@C
976    TSSetIJacobian - Set the function to compute the matrix dF/dU + a*dF/dU_t where F(t,U,U_t) is the function
977         you provided with TSSetIFunction().
978 
979    Logically Collective on TS
980 
981    Input Parameters:
982 +  ts  - the TS context obtained from TSCreate()
983 .  A   - Jacobian matrix
984 .  B   - preconditioning matrix for A (may be same as A)
985 .  f   - the Jacobian evaluation routine
986 -  ctx - user-defined context for private data for the Jacobian evaluation routine (may be PETSC_NULL)
987 
988    Calling sequence of f:
989 $  f(TS ts,PetscReal t,Vec U,Vec U_t,PetscReal a,Mat *A,Mat *B,MatStructure *flag,void *ctx);
990 
991 +  t    - time at step/stage being solved
992 .  U    - state vector
993 .  U_t  - time derivative of state vector
994 .  a    - shift
995 .  A    - Jacobian of F(t,U,W+a*U), equivalent to dF/dU + a*dF/dU_t
996 .  B    - preconditioning matrix for A, may be same as A
997 .  flag - flag indicating information about the preconditioner matrix
998           structure (same as flag in KSPSetOperators())
999 -  ctx  - [optional] user-defined context for matrix evaluation routine
1000 
1001    Notes:
1002    The matrices A and B are exactly the matrices that are used by SNES for the nonlinear solve.
1003 
1004    The matrix dF/dU + a*dF/dU_t you provide turns out to be
1005    the Jacobian of F(t,U,W+a*U) where F(t,U,U_t) = 0 is the DAE to be solved.
1006    The time integrator internally approximates U_t by W+a*U where the positive "shift"
1007    a and vector W depend on the integration method, step size, and past states. For example with
1008    the backward Euler method a = 1/dt and W = -a*U(previous timestep) so
1009    W + a*U = a*(U - U(previous timestep)) = (U - U(previous timestep))/dt
1010 
1011    Level: beginner
1012 
1013 .keywords: TS, timestep, DAE, Jacobian
1014 
1015 .seealso: TSSetIFunction(), TSSetRHSJacobian(), SNESDefaultComputeJacobianColor(), SNESDefaultComputeJacobian()
1016 
1017 @*/
1018 PetscErrorCode  TSSetIJacobian(TS ts,Mat A,Mat B,TSIJacobian f,void *ctx)
1019 {
1020   PetscErrorCode ierr;
1021   SNES           snes;
1022   DM             dm;
1023 
1024   PetscFunctionBegin;
1025   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1026   if (A) PetscValidHeaderSpecific(A,MAT_CLASSID,2);
1027   if (B) PetscValidHeaderSpecific(B,MAT_CLASSID,3);
1028   if (A) PetscCheckSameComm(ts,1,A,2);
1029   if (B) PetscCheckSameComm(ts,1,B,3);
1030 
1031   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1032   ierr = DMTSSetIJacobian(dm,f,ctx);CHKERRQ(ierr);
1033 
1034   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1035   ierr = SNESSetJacobian(snes,A,B,SNESTSFormJacobian,ts);CHKERRQ(ierr);
1036   PetscFunctionReturn(0);
1037 }
1038 
1039 #undef __FUNCT__
1040 #define __FUNCT__ "TSLoad"
1041 /*@C
1042   TSLoad - Loads a KSP that has been stored in binary  with KSPView().
1043 
1044   Collective on PetscViewer
1045 
1046   Input Parameters:
1047 + newdm - the newly loaded TS, this needs to have been created with TSCreate() or
1048            some related function before a call to TSLoad().
1049 - viewer - binary file viewer, obtained from PetscViewerBinaryOpen()
1050 
1051    Level: intermediate
1052 
1053   Notes:
1054    The type is determined by the data in the file, any type set into the TS before this call is ignored.
1055 
1056   Notes for advanced users:
1057   Most users should not need to know the details of the binary storage
1058   format, since TSLoad() and TSView() completely hide these details.
1059   But for anyone who's interested, the standard binary matrix storage
1060   format is
1061 .vb
1062      has not yet been determined
1063 .ve
1064 
1065 .seealso: PetscViewerBinaryOpen(), TSView(), MatLoad(), VecLoad()
1066 @*/
1067 PetscErrorCode  TSLoad(TS ts, PetscViewer viewer)
1068 {
1069   PetscErrorCode ierr;
1070   PetscBool      isbinary;
1071   PetscInt       classid;
1072   char           type[256];
1073   DMTS           sdm;
1074   DM             dm;
1075 
1076   PetscFunctionBegin;
1077   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1078   PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,2);
1079   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);CHKERRQ(ierr);
1080   if (!isbinary) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Invalid viewer; open viewer with PetscViewerBinaryOpen()");
1081 
1082   ierr = PetscViewerBinaryRead(viewer,&classid,1,PETSC_INT);CHKERRQ(ierr);
1083   if (classid != TS_FILE_CLASSID) SETERRQ(((PetscObject)ts)->comm,PETSC_ERR_ARG_WRONG,"Not TS next in file");
1084   ierr = PetscViewerBinaryRead(viewer,type,256,PETSC_CHAR);CHKERRQ(ierr);
1085   ierr = TSSetType(ts, type);CHKERRQ(ierr);
1086   if (ts->ops->load) {
1087     ierr = (*ts->ops->load)(ts,viewer);CHKERRQ(ierr);
1088   }
1089   ierr = DMCreate(((PetscObject)ts)->comm,&dm);CHKERRQ(ierr);
1090   ierr = DMLoad(dm,viewer);CHKERRQ(ierr);
1091   ierr = TSSetDM(ts,dm);CHKERRQ(ierr);
1092   ierr = DMCreateGlobalVector(ts->dm,&ts->vec_sol);CHKERRQ(ierr);
1093   ierr = VecLoad(ts->vec_sol,viewer);CHKERRQ(ierr);
1094   ierr = DMGetDMTS(ts->dm,&sdm);CHKERRQ(ierr);
1095   ierr = DMTSLoad(sdm,viewer);CHKERRQ(ierr);
1096   PetscFunctionReturn(0);
1097 }
1098 
1099 #undef __FUNCT__
1100 #define __FUNCT__ "TSView"
1101 /*@C
1102     TSView - Prints the TS data structure.
1103 
1104     Collective on TS
1105 
1106     Input Parameters:
1107 +   ts - the TS context obtained from TSCreate()
1108 -   viewer - visualization context
1109 
1110     Options Database Key:
1111 .   -ts_view - calls TSView() at end of TSStep()
1112 
1113     Notes:
1114     The available visualization contexts include
1115 +     PETSC_VIEWER_STDOUT_SELF - standard output (default)
1116 -     PETSC_VIEWER_STDOUT_WORLD - synchronized standard
1117          output where only the first processor opens
1118          the file.  All other processors send their
1119          data to the first processor to print.
1120 
1121     The user can open an alternative visualization context with
1122     PetscViewerASCIIOpen() - output to a specified file.
1123 
1124     Level: beginner
1125 
1126 .keywords: TS, timestep, view
1127 
1128 .seealso: PetscViewerASCIIOpen()
1129 @*/
1130 PetscErrorCode  TSView(TS ts,PetscViewer viewer)
1131 {
1132   PetscErrorCode ierr;
1133   TSType         type;
1134   PetscBool      iascii,isstring,isundials,isbinary,isdraw;
1135   DMTS           sdm;
1136 
1137   PetscFunctionBegin;
1138   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1139   if (!viewer) {
1140     ierr = PetscViewerASCIIGetStdout(((PetscObject)ts)->comm,&viewer);CHKERRQ(ierr);
1141   }
1142   PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,2);
1143   PetscCheckSameComm(ts,1,viewer,2);
1144 
1145   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr);
1146   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);CHKERRQ(ierr);
1147   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);CHKERRQ(ierr);
1148   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);CHKERRQ(ierr);
1149   if (iascii) {
1150     ierr = PetscObjectPrintClassNamePrefixType((PetscObject)ts,viewer,"TS Object");CHKERRQ(ierr);
1151     ierr = PetscViewerASCIIPrintf(viewer,"  maximum steps=%D\n",ts->max_steps);CHKERRQ(ierr);
1152     ierr = PetscViewerASCIIPrintf(viewer,"  maximum time=%G\n",ts->max_time);CHKERRQ(ierr);
1153     if (ts->problem_type == TS_NONLINEAR) {
1154       ierr = PetscViewerASCIIPrintf(viewer,"  total number of nonlinear solver iterations=%D\n",ts->snes_its);CHKERRQ(ierr);
1155       ierr = PetscViewerASCIIPrintf(viewer,"  total number of nonlinear solve failures=%D\n",ts->num_snes_failures);CHKERRQ(ierr);
1156     }
1157     ierr = PetscViewerASCIIPrintf(viewer,"  total number of linear solver iterations=%D\n",ts->ksp_its);CHKERRQ(ierr);
1158     ierr = PetscViewerASCIIPrintf(viewer,"  total number of rejected steps=%D\n",ts->reject);CHKERRQ(ierr);
1159     ierr = DMGetDMTS(ts->dm,&sdm);CHKERRQ(ierr);
1160     ierr = DMTSView(sdm,viewer);CHKERRQ(ierr);
1161     if (ts->ops->view) {
1162       ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
1163       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1164       ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
1165     }
1166   } else if (isstring) {
1167     ierr = TSGetType(ts,&type);CHKERRQ(ierr);
1168     ierr = PetscViewerStringSPrintf(viewer," %-7.7s",type);CHKERRQ(ierr);
1169   } else if (isbinary) {
1170     PetscInt         classid = TS_FILE_CLASSID;
1171     MPI_Comm         comm;
1172     PetscMPIInt      rank;
1173     char             type[256];
1174 
1175     ierr = PetscObjectGetComm((PetscObject)ts,&comm);CHKERRQ(ierr);
1176     ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
1177     if (!rank) {
1178       ierr = PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT,PETSC_FALSE);CHKERRQ(ierr);
1179       ierr = PetscStrncpy(type,((PetscObject)ts)->type_name,256);CHKERRQ(ierr);
1180       ierr = PetscViewerBinaryWrite(viewer,type,256,PETSC_CHAR,PETSC_FALSE);CHKERRQ(ierr);
1181     }
1182     if (ts->ops->view) {
1183       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1184     }
1185     ierr = DMView(ts->dm,viewer);CHKERRQ(ierr);
1186     ierr = VecView(ts->vec_sol,viewer);CHKERRQ(ierr);
1187     ierr = DMGetDMTS(ts->dm,&sdm);CHKERRQ(ierr);
1188     ierr = DMTSView(sdm,viewer);CHKERRQ(ierr);
1189   } else if (isdraw) {
1190     PetscDraw draw;
1191     char      str[36];
1192     PetscReal x,y,bottom,h;
1193 
1194     ierr = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr);
1195     ierr = PetscDrawGetCurrentPoint(draw,&x,&y);CHKERRQ(ierr);
1196     ierr = PetscStrcpy(str,"TS: ");CHKERRQ(ierr);
1197     ierr = PetscStrcat(str,((PetscObject)ts)->type_name);CHKERRQ(ierr);
1198     ierr = PetscDrawBoxedString(draw,x,y,PETSC_DRAW_BLACK,PETSC_DRAW_BLACK,str,PETSC_NULL,&h);CHKERRQ(ierr);
1199     bottom = y - h;
1200     ierr = PetscDrawPushCurrentPoint(draw,x,bottom);CHKERRQ(ierr);
1201     if (ts->ops->view) {
1202       ierr = (*ts->ops->view)(ts,viewer);CHKERRQ(ierr);
1203     }
1204     ierr = PetscDrawPopCurrentPoint(draw);CHKERRQ(ierr);
1205   }
1206   ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
1207   ierr = PetscObjectTypeCompare((PetscObject)ts,TSSUNDIALS,&isundials);CHKERRQ(ierr);
1208   ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
1209   PetscFunctionReturn(0);
1210 }
1211 
1212 
1213 #undef __FUNCT__
1214 #define __FUNCT__ "TSSetApplicationContext"
1215 /*@
1216    TSSetApplicationContext - Sets an optional user-defined context for
1217    the timesteppers.
1218 
1219    Logically Collective on TS
1220 
1221    Input Parameters:
1222 +  ts - the TS context obtained from TSCreate()
1223 -  usrP - optional user context
1224 
1225    Level: intermediate
1226 
1227 .keywords: TS, timestep, set, application, context
1228 
1229 .seealso: TSGetApplicationContext()
1230 @*/
1231 PetscErrorCode  TSSetApplicationContext(TS ts,void *usrP)
1232 {
1233   PetscFunctionBegin;
1234   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1235   ts->user = usrP;
1236   PetscFunctionReturn(0);
1237 }
1238 
1239 #undef __FUNCT__
1240 #define __FUNCT__ "TSGetApplicationContext"
1241 /*@
1242     TSGetApplicationContext - Gets the user-defined context for the
1243     timestepper.
1244 
1245     Not Collective
1246 
1247     Input Parameter:
1248 .   ts - the TS context obtained from TSCreate()
1249 
1250     Output Parameter:
1251 .   usrP - user context
1252 
1253     Level: intermediate
1254 
1255 .keywords: TS, timestep, get, application, context
1256 
1257 .seealso: TSSetApplicationContext()
1258 @*/
1259 PetscErrorCode  TSGetApplicationContext(TS ts,void *usrP)
1260 {
1261   PetscFunctionBegin;
1262   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1263   *(void**)usrP = ts->user;
1264   PetscFunctionReturn(0);
1265 }
1266 
1267 #undef __FUNCT__
1268 #define __FUNCT__ "TSGetTimeStepNumber"
1269 /*@
1270    TSGetTimeStepNumber - Gets the number of time steps completed.
1271 
1272    Not Collective
1273 
1274    Input Parameter:
1275 .  ts - the TS context obtained from TSCreate()
1276 
1277    Output Parameter:
1278 .  iter - number of steps completed so far
1279 
1280    Level: intermediate
1281 
1282 .keywords: TS, timestep, get, iteration, number
1283 .seealso: TSGetTime(), TSGetTimeStep(), TSSetPreStep(), TSSetPreStage(), TSSetPostStep()
1284 @*/
1285 PetscErrorCode  TSGetTimeStepNumber(TS ts,PetscInt* iter)
1286 {
1287   PetscFunctionBegin;
1288   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1289   PetscValidIntPointer(iter,2);
1290   *iter = ts->steps;
1291   PetscFunctionReturn(0);
1292 }
1293 
1294 #undef __FUNCT__
1295 #define __FUNCT__ "TSSetInitialTimeStep"
1296 /*@
1297    TSSetInitialTimeStep - Sets the initial timestep to be used,
1298    as well as the initial time.
1299 
1300    Logically Collective on TS
1301 
1302    Input Parameters:
1303 +  ts - the TS context obtained from TSCreate()
1304 .  initial_time - the initial time
1305 -  time_step - the size of the timestep
1306 
1307    Level: intermediate
1308 
1309 .seealso: TSSetTimeStep(), TSGetTimeStep()
1310 
1311 .keywords: TS, set, initial, timestep
1312 @*/
1313 PetscErrorCode  TSSetInitialTimeStep(TS ts,PetscReal initial_time,PetscReal time_step)
1314 {
1315   PetscErrorCode ierr;
1316 
1317   PetscFunctionBegin;
1318   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1319   ierr = TSSetTimeStep(ts,time_step);CHKERRQ(ierr);
1320   ierr = TSSetTime(ts,initial_time);CHKERRQ(ierr);
1321   PetscFunctionReturn(0);
1322 }
1323 
1324 #undef __FUNCT__
1325 #define __FUNCT__ "TSSetTimeStep"
1326 /*@
1327    TSSetTimeStep - Allows one to reset the timestep at any time,
1328    useful for simple pseudo-timestepping codes.
1329 
1330    Logically Collective on TS
1331 
1332    Input Parameters:
1333 +  ts - the TS context obtained from TSCreate()
1334 -  time_step - the size of the timestep
1335 
1336    Level: intermediate
1337 
1338 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
1339 
1340 .keywords: TS, set, timestep
1341 @*/
1342 PetscErrorCode  TSSetTimeStep(TS ts,PetscReal time_step)
1343 {
1344   PetscFunctionBegin;
1345   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1346   PetscValidLogicalCollectiveReal(ts,time_step,2);
1347   ts->time_step = time_step;
1348   ts->time_step_orig = time_step;
1349   PetscFunctionReturn(0);
1350 }
1351 
1352 #undef __FUNCT__
1353 #define __FUNCT__ "TSSetExactFinalTime"
1354 /*@
1355    TSSetExactFinalTime - Determines whether to adapt the final time step to
1356      match the exact final time, interpolate solution to the exact final time,
1357      or just return at the final time TS computed.
1358 
1359   Logically Collective on TS
1360 
1361    Input Parameter:
1362 +   ts - the time-step context
1363 -   eftopt - exact final time option
1364 
1365    Level: beginner
1366 
1367 .seealso: TSExactFinalTime
1368 @*/
1369 PetscErrorCode  TSSetExactFinalTime(TS ts,TSExactFinalTimeOption eftopt)
1370 {
1371   PetscFunctionBegin;
1372   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1373   PetscValidLogicalCollectiveEnum(ts,eftopt,2);
1374   ts->exact_final_time = eftopt;
1375   PetscFunctionReturn(0);
1376 }
1377 
1378 #undef __FUNCT__
1379 #define __FUNCT__ "TSGetTimeStep"
1380 /*@
1381    TSGetTimeStep - Gets the current timestep size.
1382 
1383    Not Collective
1384 
1385    Input Parameter:
1386 .  ts - the TS context obtained from TSCreate()
1387 
1388    Output Parameter:
1389 .  dt - the current timestep size
1390 
1391    Level: intermediate
1392 
1393 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
1394 
1395 .keywords: TS, get, timestep
1396 @*/
1397 PetscErrorCode  TSGetTimeStep(TS ts,PetscReal* dt)
1398 {
1399   PetscFunctionBegin;
1400   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1401   PetscValidRealPointer(dt,2);
1402   *dt = ts->time_step;
1403   PetscFunctionReturn(0);
1404 }
1405 
1406 #undef __FUNCT__
1407 #define __FUNCT__ "TSGetSolution"
1408 /*@
1409    TSGetSolution - Returns the solution at the present timestep. It
1410    is valid to call this routine inside the function that you are evaluating
1411    in order to move to the new timestep. This vector not changed until
1412    the solution at the next timestep has been calculated.
1413 
1414    Not Collective, but Vec returned is parallel if TS is parallel
1415 
1416    Input Parameter:
1417 .  ts - the TS context obtained from TSCreate()
1418 
1419    Output Parameter:
1420 .  v - the vector containing the solution
1421 
1422    Level: intermediate
1423 
1424 .seealso: TSGetTimeStep()
1425 
1426 .keywords: TS, timestep, get, solution
1427 @*/
1428 PetscErrorCode  TSGetSolution(TS ts,Vec *v)
1429 {
1430   PetscFunctionBegin;
1431   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1432   PetscValidPointer(v,2);
1433   *v = ts->vec_sol;
1434   PetscFunctionReturn(0);
1435 }
1436 
1437 /* ----- Routines to initialize and destroy a timestepper ---- */
1438 #undef __FUNCT__
1439 #define __FUNCT__ "TSSetProblemType"
1440 /*@
1441   TSSetProblemType - Sets the type of problem to be solved.
1442 
1443   Not collective
1444 
1445   Input Parameters:
1446 + ts   - The TS
1447 - type - One of TS_LINEAR, TS_NONLINEAR where these types refer to problems of the forms
1448 .vb
1449          U_t - A U = 0      (linear)
1450          U_t - A(t) U = 0   (linear)
1451          F(t,U,U_t) = 0     (nonlinear)
1452 .ve
1453 
1454    Level: beginner
1455 
1456 .keywords: TS, problem type
1457 .seealso: TSSetUp(), TSProblemType, TS
1458 @*/
1459 PetscErrorCode  TSSetProblemType(TS ts, TSProblemType type)
1460 {
1461   PetscErrorCode ierr;
1462 
1463   PetscFunctionBegin;
1464   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
1465   ts->problem_type = type;
1466   if (type == TS_LINEAR) {
1467     SNES snes;
1468     ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1469     ierr = SNESSetType(snes,SNESKSPONLY);CHKERRQ(ierr);
1470   }
1471   PetscFunctionReturn(0);
1472 }
1473 
1474 #undef __FUNCT__
1475 #define __FUNCT__ "TSGetProblemType"
1476 /*@C
1477   TSGetProblemType - Gets the type of problem to be solved.
1478 
1479   Not collective
1480 
1481   Input Parameter:
1482 . ts   - The TS
1483 
1484   Output Parameter:
1485 . type - One of TS_LINEAR, TS_NONLINEAR where these types refer to problems of the forms
1486 .vb
1487          M U_t = A U
1488          M(t) U_t = A(t) U
1489          F(t,U,U_t)
1490 .ve
1491 
1492    Level: beginner
1493 
1494 .keywords: TS, problem type
1495 .seealso: TSSetUp(), TSProblemType, TS
1496 @*/
1497 PetscErrorCode  TSGetProblemType(TS ts, TSProblemType *type)
1498 {
1499   PetscFunctionBegin;
1500   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
1501   PetscValidIntPointer(type,2);
1502   *type = ts->problem_type;
1503   PetscFunctionReturn(0);
1504 }
1505 
1506 #undef __FUNCT__
1507 #define __FUNCT__ "TSSetUp"
1508 /*@
1509    TSSetUp - Sets up the internal data structures for the later use
1510    of a timestepper.
1511 
1512    Collective on TS
1513 
1514    Input Parameter:
1515 .  ts - the TS context obtained from TSCreate()
1516 
1517    Notes:
1518    For basic use of the TS solvers the user need not explicitly call
1519    TSSetUp(), since these actions will automatically occur during
1520    the call to TSStep().  However, if one wishes to control this
1521    phase separately, TSSetUp() should be called after TSCreate()
1522    and optional routines of the form TSSetXXX(), but before TSStep().
1523 
1524    Level: advanced
1525 
1526 .keywords: TS, timestep, setup
1527 
1528 .seealso: TSCreate(), TSStep(), TSDestroy()
1529 @*/
1530 PetscErrorCode  TSSetUp(TS ts)
1531 {
1532   PetscErrorCode ierr;
1533   DM             dm;
1534   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
1535   PetscErrorCode (*jac)(SNES,Vec,Mat*,Mat*,MatStructure*,void*);
1536   TSIJacobian    ijac;
1537   TSRHSJacobian  rhsjac;
1538 
1539   PetscFunctionBegin;
1540   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1541   if (ts->setupcalled) PetscFunctionReturn(0);
1542 
1543   if (!((PetscObject)ts)->type_name) {
1544     ierr = TSSetType(ts,TSEULER);CHKERRQ(ierr);
1545   }
1546 
1547   if (!ts->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Must call TSSetSolution() first");
1548 
1549   ierr = TSGetTSAdapt(ts,&ts->adapt);CHKERRQ(ierr);
1550 
1551   if (ts->ops->setup) {
1552     ierr = (*ts->ops->setup)(ts);CHKERRQ(ierr);
1553   }
1554 
1555   /* in the case where we've set a DMTSFunction or what have you, we need the default SNESFunction
1556    to be set right but can't do it elsewhere due to the overreliance on ctx=ts.
1557    */
1558   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1559   ierr = DMSNESGetFunction(dm,&func,PETSC_NULL);CHKERRQ(ierr);
1560   if (!func) {
1561     ierr =DMSNESSetFunction(dm,SNESTSFormFunction,ts);CHKERRQ(ierr);
1562   }
1563   /* if the SNES doesn't have a jacobian set and the TS has an ijacobian or rhsjacobian set, set the SNES to use it.
1564      Otherwise, the SNES will use coloring internally to form the Jacobian.
1565    */
1566   ierr = DMSNESGetJacobian(dm,&jac,PETSC_NULL);CHKERRQ(ierr);
1567   ierr = DMTSGetIJacobian(dm,&ijac,PETSC_NULL);CHKERRQ(ierr);
1568   ierr = DMTSGetRHSJacobian(dm,&rhsjac,PETSC_NULL);CHKERRQ(ierr);
1569   if (!jac && (ijac || rhsjac)) {
1570     ierr = DMSNESSetJacobian(dm,SNESTSFormJacobian,ts);CHKERRQ(ierr);
1571   }
1572   ts->setupcalled = PETSC_TRUE;
1573   PetscFunctionReturn(0);
1574 }
1575 
1576 #undef __FUNCT__
1577 #define __FUNCT__ "TSReset"
1578 /*@
1579    TSReset - Resets a TS context and removes any allocated Vecs and Mats.
1580 
1581    Collective on TS
1582 
1583    Input Parameter:
1584 .  ts - the TS context obtained from TSCreate()
1585 
1586    Level: beginner
1587 
1588 .keywords: TS, timestep, reset
1589 
1590 .seealso: TSCreate(), TSSetup(), TSDestroy()
1591 @*/
1592 PetscErrorCode  TSReset(TS ts)
1593 {
1594   PetscErrorCode ierr;
1595 
1596   PetscFunctionBegin;
1597   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1598   if (ts->ops->reset) {
1599     ierr = (*ts->ops->reset)(ts);CHKERRQ(ierr);
1600   }
1601   if (ts->snes) {ierr = SNESReset(ts->snes);CHKERRQ(ierr);}
1602   ierr = MatDestroy(&ts->Arhs);CHKERRQ(ierr);
1603   ierr = MatDestroy(&ts->Brhs);CHKERRQ(ierr);
1604   ierr = VecDestroy(&ts->Frhs);CHKERRQ(ierr);
1605   ierr = VecDestroy(&ts->vec_sol);CHKERRQ(ierr);
1606   ierr = VecDestroy(&ts->vatol);CHKERRQ(ierr);
1607   ierr = VecDestroy(&ts->vrtol);CHKERRQ(ierr);
1608   ierr = VecDestroyVecs(ts->nwork,&ts->work);CHKERRQ(ierr);
1609   ts->setupcalled = PETSC_FALSE;
1610   PetscFunctionReturn(0);
1611 }
1612 
1613 #undef __FUNCT__
1614 #define __FUNCT__ "TSDestroy"
1615 /*@
1616    TSDestroy - Destroys the timestepper context that was created
1617    with TSCreate().
1618 
1619    Collective on TS
1620 
1621    Input Parameter:
1622 .  ts - the TS context obtained from TSCreate()
1623 
1624    Level: beginner
1625 
1626 .keywords: TS, timestepper, destroy
1627 
1628 .seealso: TSCreate(), TSSetUp(), TSSolve()
1629 @*/
1630 PetscErrorCode  TSDestroy(TS *ts)
1631 {
1632   PetscErrorCode ierr;
1633 
1634   PetscFunctionBegin;
1635   if (!*ts) PetscFunctionReturn(0);
1636   PetscValidHeaderSpecific((*ts),TS_CLASSID,1);
1637   if (--((PetscObject)(*ts))->refct > 0) {*ts = 0; PetscFunctionReturn(0);}
1638 
1639   ierr = TSReset((*ts));CHKERRQ(ierr);
1640 
1641   /* if memory was published with AMS then destroy it */
1642   ierr = PetscObjectDepublish((*ts));CHKERRQ(ierr);
1643   if ((*ts)->ops->destroy) {ierr = (*(*ts)->ops->destroy)((*ts));CHKERRQ(ierr);}
1644 
1645   ierr = TSAdaptDestroy(&(*ts)->adapt);CHKERRQ(ierr);
1646   ierr = SNESDestroy(&(*ts)->snes);CHKERRQ(ierr);
1647   ierr = DMDestroy(&(*ts)->dm);CHKERRQ(ierr);
1648   ierr = TSMonitorCancel((*ts));CHKERRQ(ierr);
1649 
1650   ierr = PetscHeaderDestroy(ts);CHKERRQ(ierr);
1651   PetscFunctionReturn(0);
1652 }
1653 
1654 #undef __FUNCT__
1655 #define __FUNCT__ "TSGetSNES"
1656 /*@
1657    TSGetSNES - Returns the SNES (nonlinear solver) associated with
1658    a TS (timestepper) context. Valid only for nonlinear problems.
1659 
1660    Not Collective, but SNES is parallel if TS is parallel
1661 
1662    Input Parameter:
1663 .  ts - the TS context obtained from TSCreate()
1664 
1665    Output Parameter:
1666 .  snes - the nonlinear solver context
1667 
1668    Notes:
1669    The user can then directly manipulate the SNES context to set various
1670    options, etc.  Likewise, the user can then extract and manipulate the
1671    KSP, KSP, and PC contexts as well.
1672 
1673    TSGetSNES() does not work for integrators that do not use SNES; in
1674    this case TSGetSNES() returns PETSC_NULL in snes.
1675 
1676    Level: beginner
1677 
1678 .keywords: timestep, get, SNES
1679 @*/
1680 PetscErrorCode  TSGetSNES(TS ts,SNES *snes)
1681 {
1682   PetscErrorCode ierr;
1683 
1684   PetscFunctionBegin;
1685   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1686   PetscValidPointer(snes,2);
1687   if (!ts->snes) {
1688     ierr = SNESCreate(((PetscObject)ts)->comm,&ts->snes);CHKERRQ(ierr);
1689     ierr = SNESSetFunction(ts->snes,PETSC_NULL,SNESTSFormFunction,ts);CHKERRQ(ierr);
1690     ierr = PetscLogObjectParent(ts,ts->snes);CHKERRQ(ierr);
1691     ierr = PetscObjectIncrementTabLevel((PetscObject)ts->snes,(PetscObject)ts,1);CHKERRQ(ierr);
1692     if (ts->dm) {ierr = SNESSetDM(ts->snes,ts->dm);CHKERRQ(ierr);}
1693     if (ts->problem_type == TS_LINEAR) {
1694       ierr = SNESSetType(ts->snes,SNESKSPONLY);CHKERRQ(ierr);
1695     }
1696   }
1697   *snes = ts->snes;
1698   PetscFunctionReturn(0);
1699 }
1700 
1701 #undef __FUNCT__
1702 #define __FUNCT__ "TSGetKSP"
1703 /*@
1704    TSGetKSP - Returns the KSP (linear solver) associated with
1705    a TS (timestepper) context.
1706 
1707    Not Collective, but KSP is parallel if TS is parallel
1708 
1709    Input Parameter:
1710 .  ts - the TS context obtained from TSCreate()
1711 
1712    Output Parameter:
1713 .  ksp - the nonlinear solver context
1714 
1715    Notes:
1716    The user can then directly manipulate the KSP context to set various
1717    options, etc.  Likewise, the user can then extract and manipulate the
1718    KSP and PC contexts as well.
1719 
1720    TSGetKSP() does not work for integrators that do not use KSP;
1721    in this case TSGetKSP() returns PETSC_NULL in ksp.
1722 
1723    Level: beginner
1724 
1725 .keywords: timestep, get, KSP
1726 @*/
1727 PetscErrorCode  TSGetKSP(TS ts,KSP *ksp)
1728 {
1729   PetscErrorCode ierr;
1730   SNES           snes;
1731 
1732   PetscFunctionBegin;
1733   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1734   PetscValidPointer(ksp,2);
1735   if (!((PetscObject)ts)->type_name) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"KSP is not created yet. Call TSSetType() first");
1736   if (ts->problem_type != TS_LINEAR) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Linear only; use TSGetSNES()");
1737   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
1738   ierr = SNESGetKSP(snes,ksp);CHKERRQ(ierr);
1739   PetscFunctionReturn(0);
1740 }
1741 
1742 /* ----------- Routines to set solver parameters ---------- */
1743 
1744 #undef __FUNCT__
1745 #define __FUNCT__ "TSGetDuration"
1746 /*@
1747    TSGetDuration - Gets the maximum number of timesteps to use and
1748    maximum time for iteration.
1749 
1750    Not Collective
1751 
1752    Input Parameters:
1753 +  ts       - the TS context obtained from TSCreate()
1754 .  maxsteps - maximum number of iterations to use, or PETSC_NULL
1755 -  maxtime  - final time to iterate to, or PETSC_NULL
1756 
1757    Level: intermediate
1758 
1759 .keywords: TS, timestep, get, maximum, iterations, time
1760 @*/
1761 PetscErrorCode  TSGetDuration(TS ts, PetscInt *maxsteps, PetscReal *maxtime)
1762 {
1763   PetscFunctionBegin;
1764   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
1765   if (maxsteps) {
1766     PetscValidIntPointer(maxsteps,2);
1767     *maxsteps = ts->max_steps;
1768   }
1769   if (maxtime) {
1770     PetscValidScalarPointer(maxtime,3);
1771     *maxtime  = ts->max_time;
1772   }
1773   PetscFunctionReturn(0);
1774 }
1775 
1776 #undef __FUNCT__
1777 #define __FUNCT__ "TSSetDuration"
1778 /*@
1779    TSSetDuration - Sets the maximum number of timesteps to use and
1780    maximum time for iteration.
1781 
1782    Logically Collective on TS
1783 
1784    Input Parameters:
1785 +  ts - the TS context obtained from TSCreate()
1786 .  maxsteps - maximum number of iterations to use
1787 -  maxtime - final time to iterate to
1788 
1789    Options Database Keys:
1790 .  -ts_max_steps <maxsteps> - Sets maxsteps
1791 .  -ts_final_time <maxtime> - Sets maxtime
1792 
1793    Notes:
1794    The default maximum number of iterations is 5000. Default time is 5.0
1795 
1796    Level: intermediate
1797 
1798 .keywords: TS, timestep, set, maximum, iterations
1799 
1800 .seealso: TSSetExactFinalTime()
1801 @*/
1802 PetscErrorCode  TSSetDuration(TS ts,PetscInt maxsteps,PetscReal maxtime)
1803 {
1804   PetscFunctionBegin;
1805   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1806   PetscValidLogicalCollectiveInt(ts,maxsteps,2);
1807   PetscValidLogicalCollectiveReal(ts,maxtime,2);
1808   if (maxsteps >= 0) ts->max_steps = maxsteps;
1809   if (maxtime != PETSC_DEFAULT) ts->max_time  = maxtime;
1810   PetscFunctionReturn(0);
1811 }
1812 
1813 #undef __FUNCT__
1814 #define __FUNCT__ "TSSetSolution"
1815 /*@
1816    TSSetSolution - Sets the initial solution vector
1817    for use by the TS routines.
1818 
1819    Logically Collective on TS and Vec
1820 
1821    Input Parameters:
1822 +  ts - the TS context obtained from TSCreate()
1823 -  u - the solution vector
1824 
1825    Level: beginner
1826 
1827 .keywords: TS, timestep, set, solution, initial conditions
1828 @*/
1829 PetscErrorCode  TSSetSolution(TS ts,Vec u)
1830 {
1831   PetscErrorCode ierr;
1832   DM             dm;
1833 
1834   PetscFunctionBegin;
1835   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1836   PetscValidHeaderSpecific(u,VEC_CLASSID,2);
1837   ierr = PetscObjectReference((PetscObject)u);CHKERRQ(ierr);
1838   ierr = VecDestroy(&ts->vec_sol);CHKERRQ(ierr);
1839   ts->vec_sol = u;
1840   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
1841   ierr = DMShellSetGlobalVector(dm,u);CHKERRQ(ierr);
1842   PetscFunctionReturn(0);
1843 }
1844 
1845 #undef __FUNCT__
1846 #define __FUNCT__ "TSSetPreStep"
1847 /*@C
1848   TSSetPreStep - Sets the general-purpose function
1849   called once at the beginning of each time step.
1850 
1851   Logically Collective on TS
1852 
1853   Input Parameters:
1854 + ts   - The TS context obtained from TSCreate()
1855 - func - The function
1856 
1857   Calling sequence of func:
1858 . func (TS ts);
1859 
1860   Level: intermediate
1861 
1862   Note:
1863   If a step is rejected, TSStep() will call this routine again before each attempt.
1864   The last completed time step number can be queried using TSGetTimeStepNumber(), the
1865   size of the step being attempted can be obtained using TSGetTimeStep().
1866 
1867 .keywords: TS, timestep
1868 .seealso: TSSetPreStage(), TSSetPostStep(), TSStep()
1869 @*/
1870 PetscErrorCode  TSSetPreStep(TS ts, PetscErrorCode (*func)(TS))
1871 {
1872   PetscFunctionBegin;
1873   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
1874   ts->ops->prestep = func;
1875   PetscFunctionReturn(0);
1876 }
1877 
1878 #undef __FUNCT__
1879 #define __FUNCT__ "TSPreStep"
1880 /*@
1881   TSPreStep - Runs the user-defined pre-step function.
1882 
1883   Collective on TS
1884 
1885   Input Parameters:
1886 . ts   - The TS context obtained from TSCreate()
1887 
1888   Notes:
1889   TSPreStep() is typically used within time stepping implementations,
1890   so most users would not generally call this routine themselves.
1891 
1892   Level: developer
1893 
1894 .keywords: TS, timestep
1895 .seealso: TSSetPreStep(), TSPreStage(), TSPostStep()
1896 @*/
1897 PetscErrorCode  TSPreStep(TS ts)
1898 {
1899   PetscErrorCode ierr;
1900 
1901   PetscFunctionBegin;
1902   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1903   if (ts->ops->prestep) {
1904     PetscStackPush("TS PreStep function");
1905     ierr = (*ts->ops->prestep)(ts);CHKERRQ(ierr);
1906     PetscStackPop;
1907   }
1908   PetscFunctionReturn(0);
1909 }
1910 
1911 #undef __FUNCT__
1912 #define __FUNCT__ "TSSetPreStage"
1913 /*@C
1914   TSSetPreStage - Sets the general-purpose function
1915   called once at the beginning of each stage.
1916 
1917   Logically Collective on TS
1918 
1919   Input Parameters:
1920 + ts   - The TS context obtained from TSCreate()
1921 - func - The function
1922 
1923   Calling sequence of func:
1924 . PetscErrorCode func(TS ts, PetscReal stagetime);
1925 
1926   Level: intermediate
1927 
1928   Note:
1929   There may be several stages per time step. If the solve for a given stage fails, the step may be rejected and retried.
1930   The time step number being computed can be queried using TSGetTimeStepNumber() and the total size of the step being
1931   attempted can be obtained using TSGetTimeStep(). The time at the start of the step is available via TSGetTime().
1932 
1933 .keywords: TS, timestep
1934 .seealso: TSSetPreStep(), TSSetPostStep(), TSGetApplicationContext()
1935 @*/
1936 PetscErrorCode  TSSetPreStage(TS ts, PetscErrorCode (*func)(TS,PetscReal))
1937 {
1938   PetscFunctionBegin;
1939   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
1940   ts->ops->prestage = func;
1941   PetscFunctionReturn(0);
1942 }
1943 
1944 #undef __FUNCT__
1945 #define __FUNCT__ "TSPreStage"
1946 /*@
1947   TSPreStage - Runs the user-defined pre-stage function set using TSSetPreStage()
1948 
1949   Collective on TS
1950 
1951   Input Parameters:
1952 . ts   - The TS context obtained from TSCreate()
1953 
1954   Notes:
1955   TSPreStage() is typically used within time stepping implementations,
1956   most users would not generally call this routine themselves.
1957 
1958   Level: developer
1959 
1960 .keywords: TS, timestep
1961 .seealso: TSSetPreStep(), TSPreStep(), TSPostStep()
1962 @*/
1963 PetscErrorCode  TSPreStage(TS ts, PetscReal stagetime)
1964 {
1965   PetscErrorCode ierr;
1966 
1967   PetscFunctionBegin;
1968   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
1969   if (ts->ops->prestage) {
1970     PetscStackPush("TS PreStage function");
1971     ierr = (*ts->ops->prestage)(ts,stagetime);CHKERRQ(ierr);
1972     PetscStackPop;
1973   }
1974   PetscFunctionReturn(0);
1975 }
1976 
1977 #undef __FUNCT__
1978 #define __FUNCT__ "TSSetPostStep"
1979 /*@C
1980   TSSetPostStep - Sets the general-purpose function
1981   called once at the end of each time step.
1982 
1983   Logically Collective on TS
1984 
1985   Input Parameters:
1986 + ts   - The TS context obtained from TSCreate()
1987 - func - The function
1988 
1989   Calling sequence of func:
1990 $ func (TS ts);
1991 
1992   Level: intermediate
1993 
1994 .keywords: TS, timestep
1995 .seealso: TSSetPreStep(), TSSetPreStage(), TSGetTimeStep(), TSGetTimeStepNumber(), TSGetTime()
1996 @*/
1997 PetscErrorCode  TSSetPostStep(TS ts, PetscErrorCode (*func)(TS))
1998 {
1999   PetscFunctionBegin;
2000   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2001   ts->ops->poststep = func;
2002   PetscFunctionReturn(0);
2003 }
2004 
2005 #undef __FUNCT__
2006 #define __FUNCT__ "TSPostStep"
2007 /*@
2008   TSPostStep - Runs the user-defined post-step function.
2009 
2010   Collective on TS
2011 
2012   Input Parameters:
2013 . ts   - The TS context obtained from TSCreate()
2014 
2015   Notes:
2016   TSPostStep() is typically used within time stepping implementations,
2017   so most users would not generally call this routine themselves.
2018 
2019   Level: developer
2020 
2021 .keywords: TS, timestep
2022 @*/
2023 PetscErrorCode  TSPostStep(TS ts)
2024 {
2025   PetscErrorCode ierr;
2026 
2027   PetscFunctionBegin;
2028   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2029   if (ts->ops->poststep) {
2030     PetscStackPush("TS PostStep function");
2031     ierr = (*ts->ops->poststep)(ts);CHKERRQ(ierr);
2032     PetscStackPop;
2033   }
2034   PetscFunctionReturn(0);
2035 }
2036 
2037 /* ------------ Routines to set performance monitoring options ----------- */
2038 
2039 #undef __FUNCT__
2040 #define __FUNCT__ "TSMonitorSet"
2041 /*@C
2042    TSMonitorSet - Sets an ADDITIONAL function that is to be used at every
2043    timestep to display the iteration's  progress.
2044 
2045    Logically Collective on TS
2046 
2047    Input Parameters:
2048 +  ts - the TS context obtained from TSCreate()
2049 .  monitor - monitoring routine
2050 .  mctx - [optional] user-defined context for private data for the
2051              monitor routine (use PETSC_NULL if no context is desired)
2052 -  monitordestroy - [optional] routine that frees monitor context
2053           (may be PETSC_NULL)
2054 
2055    Calling sequence of monitor:
2056 $    int monitor(TS ts,PetscInt steps,PetscReal time,Vec u,void *mctx)
2057 
2058 +    ts - the TS context
2059 .    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
2060                                been interpolated to)
2061 .    time - current time
2062 .    u - current iterate
2063 -    mctx - [optional] monitoring context
2064 
2065    Notes:
2066    This routine adds an additional monitor to the list of monitors that
2067    already has been loaded.
2068 
2069    Fortran notes: Only a single monitor function can be set for each TS object
2070 
2071    Level: intermediate
2072 
2073 .keywords: TS, timestep, set, monitor
2074 
2075 .seealso: TSMonitorDefault(), TSMonitorCancel()
2076 @*/
2077 PetscErrorCode  TSMonitorSet(TS ts,PetscErrorCode (*monitor)(TS,PetscInt,PetscReal,Vec,void*),void *mctx,PetscErrorCode (*mdestroy)(void**))
2078 {
2079   PetscFunctionBegin;
2080   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2081   if (ts->numbermonitors >= MAXTSMONITORS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
2082   ts->monitor[ts->numbermonitors]           = monitor;
2083   ts->monitordestroy[ts->numbermonitors]    = mdestroy;
2084   ts->monitorcontext[ts->numbermonitors++]  = (void*)mctx;
2085   PetscFunctionReturn(0);
2086 }
2087 
2088 #undef __FUNCT__
2089 #define __FUNCT__ "TSMonitorCancel"
2090 /*@C
2091    TSMonitorCancel - Clears all the monitors that have been set on a time-step object.
2092 
2093    Logically Collective on TS
2094 
2095    Input Parameters:
2096 .  ts - the TS context obtained from TSCreate()
2097 
2098    Notes:
2099    There is no way to remove a single, specific monitor.
2100 
2101    Level: intermediate
2102 
2103 .keywords: TS, timestep, set, monitor
2104 
2105 .seealso: TSMonitorDefault(), TSMonitorSet()
2106 @*/
2107 PetscErrorCode  TSMonitorCancel(TS ts)
2108 {
2109   PetscErrorCode ierr;
2110   PetscInt       i;
2111 
2112   PetscFunctionBegin;
2113   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2114   for (i=0; i<ts->numbermonitors; i++) {
2115     if (ts->monitordestroy[i]) {
2116       ierr = (*ts->monitordestroy[i])(&ts->monitorcontext[i]);CHKERRQ(ierr);
2117     }
2118   }
2119   ts->numbermonitors = 0;
2120   PetscFunctionReturn(0);
2121 }
2122 
2123 #undef __FUNCT__
2124 #define __FUNCT__ "TSMonitorDefault"
2125 /*@
2126    TSMonitorDefault - Sets the Default monitor
2127 
2128    Level: intermediate
2129 
2130 .keywords: TS, set, monitor
2131 
2132 .seealso: TSMonitorDefault(), TSMonitorSet()
2133 @*/
2134 PetscErrorCode TSMonitorDefault(TS ts,PetscInt step,PetscReal ptime,Vec v,void *dummy)
2135 {
2136   PetscErrorCode ierr;
2137   PetscViewer    viewer = dummy ? (PetscViewer) dummy : PETSC_VIEWER_STDOUT_(((PetscObject)ts)->comm);
2138 
2139   PetscFunctionBegin;
2140   ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)ts)->tablevel);CHKERRQ(ierr);
2141   ierr = PetscViewerASCIIPrintf(viewer,"%D TS dt %g time %g\n",step,(double)ts->time_step,(double)ptime);CHKERRQ(ierr);
2142   ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)ts)->tablevel);CHKERRQ(ierr);
2143   PetscFunctionReturn(0);
2144 }
2145 
2146 #undef __FUNCT__
2147 #define __FUNCT__ "TSSetRetainStages"
2148 /*@
2149    TSSetRetainStages - Request that all stages in the upcoming step be stored so that interpolation will be available.
2150 
2151    Logically Collective on TS
2152 
2153    Input Argument:
2154 .  ts - time stepping context
2155 
2156    Output Argument:
2157 .  flg - PETSC_TRUE or PETSC_FALSE
2158 
2159    Level: intermediate
2160 
2161 .keywords: TS, set
2162 
2163 .seealso: TSInterpolate(), TSSetPostStep()
2164 @*/
2165 PetscErrorCode TSSetRetainStages(TS ts,PetscBool flg)
2166 {
2167   PetscFunctionBegin;
2168   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2169   ts->retain_stages = flg;
2170   PetscFunctionReturn(0);
2171 }
2172 
2173 #undef __FUNCT__
2174 #define __FUNCT__ "TSInterpolate"
2175 /*@
2176    TSInterpolate - Interpolate the solution computed during the previous step to an arbitrary location in the interval
2177 
2178    Collective on TS
2179 
2180    Input Argument:
2181 +  ts - time stepping context
2182 -  t - time to interpolate to
2183 
2184    Output Argument:
2185 .  U - state at given time
2186 
2187    Notes:
2188    The user should call TSSetRetainStages() before taking a step in which interpolation will be requested.
2189 
2190    Level: intermediate
2191 
2192    Developer Notes:
2193    TSInterpolate() and the storing of previous steps/stages should be generalized to support delay differential equations and continuous adjoints.
2194 
2195 .keywords: TS, set
2196 
2197 .seealso: TSSetRetainStages(), TSSetPostStep()
2198 @*/
2199 PetscErrorCode TSInterpolate(TS ts,PetscReal t,Vec U)
2200 {
2201   PetscErrorCode ierr;
2202 
2203   PetscFunctionBegin;
2204   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2205   if (t < ts->ptime - ts->time_step_prev || t > ts->ptime) SETERRQ3(((PetscObject)ts)->comm,PETSC_ERR_ARG_OUTOFRANGE,"Requested time %G not in last time steps [%G,%G]",t,ts->ptime-ts->time_step_prev,ts->ptime);
2206   if (!ts->ops->interpolate) SETERRQ1(((PetscObject)ts)->comm,PETSC_ERR_SUP,"%s does not provide interpolation",((PetscObject)ts)->type_name);
2207   ierr = (*ts->ops->interpolate)(ts,t,U);CHKERRQ(ierr);
2208   PetscFunctionReturn(0);
2209 }
2210 
2211 #undef __FUNCT__
2212 #define __FUNCT__ "TSStep"
2213 /*@
2214    TSStep - Steps one time step
2215 
2216    Collective on TS
2217 
2218    Input Parameter:
2219 .  ts - the TS context obtained from TSCreate()
2220 
2221    Level: intermediate
2222 
2223    Notes:
2224    The hook set using TSSetPreStep() is called before each attempt to take the step. In general, the time step size may
2225    be changed due to adaptive error controller or solve failures. Note that steps may contain multiple stages.
2226 
2227    This may over-step the final time provided in TSSetDuration() depending on the time-step used. TSSolve() interpolates to exactly the
2228    time provided in TSSetDuration(). One can use TSInterpolate() to determine an interpolated solution within the final timestep.
2229 
2230 .keywords: TS, timestep, solve
2231 
2232 .seealso: TSCreate(), TSSetUp(), TSDestroy(), TSSolve(), TSSetPreStep(), TSSetPreStage(), TSInterpolate()
2233 @*/
2234 PetscErrorCode  TSStep(TS ts)
2235 {
2236   PetscReal      ptime_prev;
2237   PetscErrorCode ierr;
2238 
2239   PetscFunctionBegin;
2240   PetscValidHeaderSpecific(ts, TS_CLASSID,1);
2241   ierr = TSSetUp(ts);CHKERRQ(ierr);
2242 
2243   ts->reason = TS_CONVERGED_ITERATING;
2244 
2245   ptime_prev = ts->ptime;
2246   ierr = PetscLogEventBegin(TS_Step,ts,0,0,0);CHKERRQ(ierr);
2247   ierr = (*ts->ops->step)(ts);CHKERRQ(ierr);
2248   ierr = PetscLogEventEnd(TS_Step,ts,0,0,0);CHKERRQ(ierr);
2249   ts->time_step_prev = ts->ptime - ptime_prev;
2250 
2251   if (ts->reason < 0) {
2252     if (ts->errorifstepfailed) {
2253       if (ts->reason == TS_DIVERGED_NONLINEAR_SOLVE) {
2254         SETERRQ1(((PetscObject)ts)->comm,PETSC_ERR_NOT_CONVERGED,"TSStep has failed due to %s, increase -ts_max_snes_failures or make negative to attempt recovery",TSConvergedReasons[ts->reason]);
2255       } else SETERRQ1(((PetscObject)ts)->comm,PETSC_ERR_NOT_CONVERGED,"TSStep has failed due to %s",TSConvergedReasons[ts->reason]);
2256     }
2257   } else if (!ts->reason) {
2258     if (ts->steps >= ts->max_steps)
2259       ts->reason = TS_CONVERGED_ITS;
2260     else if (ts->ptime >= ts->max_time)
2261       ts->reason = TS_CONVERGED_TIME;
2262   }
2263 
2264   PetscFunctionReturn(0);
2265 }
2266 
2267 #undef __FUNCT__
2268 #define __FUNCT__ "TSEvaluateStep"
2269 /*@
2270    TSEvaluateStep - Evaluate the solution at the end of a time step with a given order of accuracy.
2271 
2272    Collective on TS
2273 
2274    Input Arguments:
2275 +  ts - time stepping context
2276 .  order - desired order of accuracy
2277 -  done - whether the step was evaluated at this order (pass PETSC_NULL to generate an error if not available)
2278 
2279    Output Arguments:
2280 .  U - state at the end of the current step
2281 
2282    Level: advanced
2283 
2284    Notes:
2285    This function cannot be called until all stages have been evaluated.
2286    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.
2287 
2288 .seealso: TSStep(), TSAdapt
2289 @*/
2290 PetscErrorCode TSEvaluateStep(TS ts,PetscInt order,Vec U,PetscBool *done)
2291 {
2292   PetscErrorCode ierr;
2293 
2294   PetscFunctionBegin;
2295   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2296   PetscValidType(ts,1);
2297   PetscValidHeaderSpecific(U,VEC_CLASSID,3);
2298   if (!ts->ops->evaluatestep) SETERRQ1(((PetscObject)ts)->comm,PETSC_ERR_SUP,"TSEvaluateStep not implemented for type '%s'",((PetscObject)ts)->type_name);
2299   ierr = (*ts->ops->evaluatestep)(ts,order,U,done);CHKERRQ(ierr);
2300   PetscFunctionReturn(0);
2301 }
2302 
2303 #undef __FUNCT__
2304 #define __FUNCT__ "TSSolve"
2305 /*@
2306    TSSolve - Steps the requested number of timesteps.
2307 
2308    Collective on TS
2309 
2310    Input Parameter:
2311 +  ts - the TS context obtained from TSCreate()
2312 -  u - the solution vector  (can be null if TSSetSolution() was used, otherwise must contain the initial conditions)
2313 
2314    Level: beginner
2315 
2316    Notes:
2317    The final time returned by this function may be different from the time of the internally
2318    held state accessible by TSGetSolution() and TSGetTime() because the method may have
2319    stepped over the final time.
2320 
2321 .keywords: TS, timestep, solve
2322 
2323 .seealso: TSCreate(), TSSetSolution(), TSStep()
2324 @*/
2325 PetscErrorCode TSSolve(TS ts,Vec u)
2326 {
2327   PetscBool         flg;
2328   PetscViewer       viewer;
2329   PetscErrorCode    ierr;
2330   PetscViewerFormat format;
2331 
2332   PetscFunctionBegin;
2333   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2334   if (u) PetscValidHeaderSpecific(u,VEC_CLASSID,2);
2335   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 */
2336     if (!ts->vec_sol || u == ts->vec_sol) {
2337       Vec y;
2338       ierr = VecDuplicate(u,&y);CHKERRQ(ierr);
2339       ierr = TSSetSolution(ts,y);CHKERRQ(ierr);
2340       ierr = VecDestroy(&y);CHKERRQ(ierr); /* grant ownership */
2341     }
2342     if (u) {
2343       ierr = VecCopy(u,ts->vec_sol);CHKERRQ(ierr);
2344     }
2345   } else {
2346     if (u) {
2347       ierr = TSSetSolution(ts,u);CHKERRQ(ierr);
2348     }
2349   }
2350   ierr = TSSetUp(ts);CHKERRQ(ierr);
2351   /* reset time step and iteration counters */
2352   ts->steps = 0;
2353   ts->ksp_its = 0;
2354   ts->snes_its = 0;
2355   ts->num_snes_failures = 0;
2356   ts->reject = 0;
2357   ts->reason = TS_CONVERGED_ITERATING;
2358 
2359   if (ts->ops->solve) {         /* This private interface is transitional and should be removed when all implementations are updated. */
2360     ierr = (*ts->ops->solve)(ts);CHKERRQ(ierr);
2361     ierr = VecCopy(ts->vec_sol,u);CHKERRQ(ierr);
2362     ts->solvetime = ts->ptime;
2363   } else {
2364     /* steps the requested number of timesteps. */
2365     ierr = TSMonitor(ts,ts->steps,ts->ptime,ts->vec_sol);CHKERRQ(ierr);
2366     if (ts->steps >= ts->max_steps)
2367       ts->reason = TS_CONVERGED_ITS;
2368     else if (ts->ptime >= ts->max_time)
2369       ts->reason = TS_CONVERGED_TIME;
2370     while (!ts->reason) {
2371       ierr = TSStep(ts);CHKERRQ(ierr);
2372       ierr = TSPostStep(ts);CHKERRQ(ierr);
2373       ierr = TSMonitor(ts,ts->steps,ts->ptime,ts->vec_sol);CHKERRQ(ierr);
2374     }
2375     if (ts->exact_final_time == TS_EXACTFINALTIME_INTERPOLATE && ts->ptime > ts->max_time) {
2376       ierr = TSInterpolate(ts,ts->max_time,u);CHKERRQ(ierr);
2377       ts->solvetime = ts->max_time;
2378     } else {
2379       if (u) {ierr = VecCopy(ts->vec_sol,u);CHKERRQ(ierr);}
2380       ts->solvetime = ts->ptime;
2381     }
2382   }
2383   ierr = TSMonitor(ts,-1,ts->ptime,ts->vec_sol);CHKERRQ(ierr);
2384   ierr = PetscOptionsGetViewer(((PetscObject)ts)->comm,((PetscObject)ts)->prefix,"-ts_view",&viewer,&format,&flg);CHKERRQ(ierr);
2385   if (flg && !PetscPreLoadingOn) {
2386     ierr = PetscViewerPushFormat(viewer,format);CHKERRQ(ierr);
2387     ierr = TSView(ts,viewer);CHKERRQ(ierr);
2388     ierr = PetscViewerPopFormat(viewer);CHKERRQ(ierr);
2389     ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
2390   }
2391   PetscFunctionReturn(0);
2392 }
2393 
2394 #undef __FUNCT__
2395 #define __FUNCT__ "TSMonitor"
2396 /*@
2397    TSMonitor - Runs all user-provided monitor routines set using TSMonitorSet()
2398 
2399    Collective on TS
2400 
2401    Input Parameters:
2402 +  ts - time stepping context obtained from TSCreate()
2403 .  step - step number that has just completed
2404 .  ptime - model time of the state
2405 -  u - state at the current model time
2406 
2407    Notes:
2408    TSMonitor() is typically used within the time stepping implementations.
2409    Users might call this function when using the TSStep() interface instead of TSSolve().
2410 
2411    Level: advanced
2412 
2413 .keywords: TS, timestep
2414 @*/
2415 PetscErrorCode TSMonitor(TS ts,PetscInt step,PetscReal ptime,Vec u)
2416 {
2417   PetscErrorCode ierr;
2418   PetscInt       i,n = ts->numbermonitors;
2419 
2420   PetscFunctionBegin;
2421   for (i=0; i<n; i++) {
2422     ierr = (*ts->monitor[i])(ts,step,ptime,u,ts->monitorcontext[i]);CHKERRQ(ierr);
2423   }
2424   PetscFunctionReturn(0);
2425 }
2426 
2427 /* ------------------------------------------------------------------------*/
2428 struct _n_TSMonitorLGCtx {
2429   PetscDrawLG lg;
2430   PetscInt    howoften;  /* when > 0 uses step % howoften, when negative only final solution plotted */
2431   PetscInt    ksp_its,snes_its;
2432 };
2433 
2434 
2435 #undef __FUNCT__
2436 #define __FUNCT__ "TSMonitorLGCtxCreate"
2437 /*@C
2438    TSMonitorLGCtxCreate - Creates a line graph context for use with
2439    TS to monitor the solution process graphically in various ways
2440 
2441    Collective on TS
2442 
2443    Input Parameters:
2444 +  host - the X display to open, or null for the local machine
2445 .  label - the title to put in the title bar
2446 .  x, y - the screen coordinates of the upper left coordinate of the window
2447 .  m, n - the screen width and height in pixels
2448 -  howoften - if positive then determines the frequency of the plotting, if -1 then only at the final time
2449 
2450    Output Parameter:
2451 .  ctx - the context
2452 
2453    Options Database Key:
2454 +  -ts_monitor_lg_timestep - automatically sets line graph monitor
2455 .  -ts_monitor_lg_solution -
2456 .  -ts_monitor_lg_error -
2457 .  -ts_monitor_lg_ksp_iterations -
2458 .  -ts_monitor_lg_snes_iterations -
2459 -  -lg_indicate_data_points <true,false> - indicate the data points (at each time step) on the plot; default is true
2460 
2461    Notes:
2462    Use TSMonitorLGCtxDestroy() to destroy.
2463 
2464    Level: intermediate
2465 
2466 .keywords: TS, monitor, line graph, residual, seealso
2467 
2468 .seealso: TSMonitorLGTimeStep(), TSMonitorSet(), TSMonitorLGSolution(), TSMonitorLGError()
2469 
2470 @*/
2471 PetscErrorCode  TSMonitorLGCtxCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscInt howoften,TSMonitorLGCtx *ctx)
2472 {
2473   PetscDraw      win;
2474   PetscErrorCode ierr;
2475   PetscBool      flg = PETSC_TRUE;
2476 
2477   PetscFunctionBegin;
2478   ierr = PetscNew(struct _n_TSMonitorLGCtx,ctx);CHKERRQ(ierr);
2479   ierr = PetscDrawCreate(comm,host,label,x,y,m,n,&win);CHKERRQ(ierr);
2480   ierr = PetscDrawSetFromOptions(win);CHKERRQ(ierr);
2481   ierr = PetscDrawLGCreate(win,1,&(*ctx)->lg);CHKERRQ(ierr);
2482   ierr = PetscOptionsGetBool(PETSC_NULL,"-lg_indicate_data_points",&flg,PETSC_NULL);CHKERRQ(ierr);
2483   if (flg) {
2484     ierr = PetscDrawLGIndicateDataPoints((*ctx)->lg);CHKERRQ(ierr);
2485   }
2486   ierr = PetscLogObjectParent((*ctx)->lg,win);CHKERRQ(ierr);
2487   (*ctx)->howoften = howoften;
2488   PetscFunctionReturn(0);
2489 }
2490 
2491 #undef __FUNCT__
2492 #define __FUNCT__ "TSMonitorLGTimeStep"
2493 PetscErrorCode TSMonitorLGTimeStep(TS ts,PetscInt n,PetscReal ptime,Vec v,void *monctx)
2494 {
2495   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
2496   PetscReal      x = ptime,y;
2497   PetscErrorCode ierr;
2498 
2499   PetscFunctionBegin;
2500   if (!n) {
2501     PetscDrawAxis  axis;
2502     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
2503     ierr = PetscDrawAxisSetLabels(axis,"Timestep as function of time","Time","Time step");CHKERRQ(ierr);
2504     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
2505   }
2506   ierr = TSGetTimeStep(ts,&y);CHKERRQ(ierr);
2507   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
2508   if (((ctx->howoften > 0) && (!(n % ctx->howoften))) || ((ctx->howoften == -1) && (n == -1))){
2509     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
2510   }
2511   PetscFunctionReturn(0);
2512 }
2513 
2514 #undef __FUNCT__
2515 #define __FUNCT__ "TSMonitorLGCtxDestroy"
2516 /*@C
2517    TSMonitorLGCtxDestroy - Destroys a line graph context that was created
2518    with TSMonitorLGCtxCreate().
2519 
2520    Collective on TSMonitorLGCtx
2521 
2522    Input Parameter:
2523 .  ctx - the monitor context
2524 
2525    Level: intermediate
2526 
2527 .keywords: TS, monitor, line graph, destroy
2528 
2529 .seealso: TSMonitorLGCtxCreate(),  TSMonitorSet(), TSMonitorLGTimeStep();
2530 @*/
2531 PetscErrorCode  TSMonitorLGCtxDestroy(TSMonitorLGCtx *ctx)
2532 {
2533   PetscDraw      draw;
2534   PetscErrorCode ierr;
2535 
2536   PetscFunctionBegin;
2537   ierr = PetscDrawLGGetDraw((*ctx)->lg,&draw);CHKERRQ(ierr);
2538   ierr = PetscDrawDestroy(&draw);CHKERRQ(ierr);
2539   ierr = PetscDrawLGDestroy(&(*ctx)->lg);CHKERRQ(ierr);
2540   ierr = PetscFree(*ctx);CHKERRQ(ierr);
2541   PetscFunctionReturn(0);
2542 }
2543 
2544 #undef __FUNCT__
2545 #define __FUNCT__ "TSGetTime"
2546 /*@
2547    TSGetTime - Gets the time of the most recently completed step.
2548 
2549    Not Collective
2550 
2551    Input Parameter:
2552 .  ts - the TS context obtained from TSCreate()
2553 
2554    Output Parameter:
2555 .  t  - the current time
2556 
2557    Level: beginner
2558 
2559    Note:
2560    When called during time step evaluation (e.g. during residual evaluation or via hooks set using TSSetPreStep(),
2561    TSSetPreStage(), or TSSetPostStep()), the time is the time at the start of the step being evaluated.
2562 
2563 .seealso: TSSetInitialTimeStep(), TSGetTimeStep()
2564 
2565 .keywords: TS, get, time
2566 @*/
2567 PetscErrorCode  TSGetTime(TS ts,PetscReal* t)
2568 {
2569   PetscFunctionBegin;
2570   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2571   PetscValidRealPointer(t,2);
2572   *t = ts->ptime;
2573   PetscFunctionReturn(0);
2574 }
2575 
2576 #undef __FUNCT__
2577 #define __FUNCT__ "TSSetTime"
2578 /*@
2579    TSSetTime - Allows one to reset the time.
2580 
2581    Logically Collective on TS
2582 
2583    Input Parameters:
2584 +  ts - the TS context obtained from TSCreate()
2585 -  time - the time
2586 
2587    Level: intermediate
2588 
2589 .seealso: TSGetTime(), TSSetDuration()
2590 
2591 .keywords: TS, set, time
2592 @*/
2593 PetscErrorCode  TSSetTime(TS ts, PetscReal t)
2594 {
2595   PetscFunctionBegin;
2596   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2597   PetscValidLogicalCollectiveReal(ts,t,2);
2598   ts->ptime = t;
2599   PetscFunctionReturn(0);
2600 }
2601 
2602 #undef __FUNCT__
2603 #define __FUNCT__ "TSSetOptionsPrefix"
2604 /*@C
2605    TSSetOptionsPrefix - Sets the prefix used for searching for all
2606    TS options in the database.
2607 
2608    Logically Collective on TS
2609 
2610    Input Parameter:
2611 +  ts     - The TS context
2612 -  prefix - The prefix to prepend to all option names
2613 
2614    Notes:
2615    A hyphen (-) must NOT be given at the beginning of the prefix name.
2616    The first character of all runtime options is AUTOMATICALLY the
2617    hyphen.
2618 
2619    Level: advanced
2620 
2621 .keywords: TS, set, options, prefix, database
2622 
2623 .seealso: TSSetFromOptions()
2624 
2625 @*/
2626 PetscErrorCode  TSSetOptionsPrefix(TS ts,const char prefix[])
2627 {
2628   PetscErrorCode ierr;
2629   SNES           snes;
2630 
2631   PetscFunctionBegin;
2632   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2633   ierr = PetscObjectSetOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
2634   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2635   ierr = SNESSetOptionsPrefix(snes,prefix);CHKERRQ(ierr);
2636   PetscFunctionReturn(0);
2637 }
2638 
2639 
2640 #undef __FUNCT__
2641 #define __FUNCT__ "TSAppendOptionsPrefix"
2642 /*@C
2643    TSAppendOptionsPrefix - Appends to the prefix used for searching for all
2644    TS options in the database.
2645 
2646    Logically Collective on TS
2647 
2648    Input Parameter:
2649 +  ts     - The TS context
2650 -  prefix - The prefix to prepend to all option names
2651 
2652    Notes:
2653    A hyphen (-) must NOT be given at the beginning of the prefix name.
2654    The first character of all runtime options is AUTOMATICALLY the
2655    hyphen.
2656 
2657    Level: advanced
2658 
2659 .keywords: TS, append, options, prefix, database
2660 
2661 .seealso: TSGetOptionsPrefix()
2662 
2663 @*/
2664 PetscErrorCode  TSAppendOptionsPrefix(TS ts,const char prefix[])
2665 {
2666   PetscErrorCode ierr;
2667   SNES           snes;
2668 
2669   PetscFunctionBegin;
2670   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2671   ierr = PetscObjectAppendOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
2672   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2673   ierr = SNESAppendOptionsPrefix(snes,prefix);CHKERRQ(ierr);
2674   PetscFunctionReturn(0);
2675 }
2676 
2677 #undef __FUNCT__
2678 #define __FUNCT__ "TSGetOptionsPrefix"
2679 /*@C
2680    TSGetOptionsPrefix - Sets the prefix used for searching for all
2681    TS options in the database.
2682 
2683    Not Collective
2684 
2685    Input Parameter:
2686 .  ts - The TS context
2687 
2688    Output Parameter:
2689 .  prefix - A pointer to the prefix string used
2690 
2691    Notes: On the fortran side, the user should pass in a string 'prifix' of
2692    sufficient length to hold the prefix.
2693 
2694    Level: intermediate
2695 
2696 .keywords: TS, get, options, prefix, database
2697 
2698 .seealso: TSAppendOptionsPrefix()
2699 @*/
2700 PetscErrorCode  TSGetOptionsPrefix(TS ts,const char *prefix[])
2701 {
2702   PetscErrorCode ierr;
2703 
2704   PetscFunctionBegin;
2705   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2706   PetscValidPointer(prefix,2);
2707   ierr = PetscObjectGetOptionsPrefix((PetscObject)ts,prefix);CHKERRQ(ierr);
2708   PetscFunctionReturn(0);
2709 }
2710 
2711 #undef __FUNCT__
2712 #define __FUNCT__ "TSGetRHSJacobian"
2713 /*@C
2714    TSGetRHSJacobian - Returns the Jacobian J at the present timestep.
2715 
2716    Not Collective, but parallel objects are returned if TS is parallel
2717 
2718    Input Parameter:
2719 .  ts  - The TS context obtained from TSCreate()
2720 
2721    Output Parameters:
2722 +  J   - The Jacobian J of F, where U_t = G(U,t)
2723 .  M   - The preconditioner matrix, usually the same as J
2724 .  func - Function to compute the Jacobian of the RHS
2725 -  ctx - User-defined context for Jacobian evaluation routine
2726 
2727    Notes: You can pass in PETSC_NULL for any return argument you do not need.
2728 
2729    Level: intermediate
2730 
2731 .seealso: TSGetTimeStep(), TSGetMatrices(), TSGetTime(), TSGetTimeStepNumber()
2732 
2733 .keywords: TS, timestep, get, matrix, Jacobian
2734 @*/
2735 PetscErrorCode  TSGetRHSJacobian(TS ts,Mat *J,Mat *M,TSRHSJacobian *func,void **ctx)
2736 {
2737   PetscErrorCode ierr;
2738   SNES           snes;
2739   DM             dm;
2740 
2741   PetscFunctionBegin;
2742   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2743   ierr = SNESGetJacobian(snes,J,M,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
2744   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
2745   ierr = DMTSGetRHSJacobian(dm,func,ctx);CHKERRQ(ierr);
2746   PetscFunctionReturn(0);
2747 }
2748 
2749 #undef __FUNCT__
2750 #define __FUNCT__ "TSGetIJacobian"
2751 /*@C
2752    TSGetIJacobian - Returns the implicit Jacobian at the present timestep.
2753 
2754    Not Collective, but parallel objects are returned if TS is parallel
2755 
2756    Input Parameter:
2757 .  ts  - The TS context obtained from TSCreate()
2758 
2759    Output Parameters:
2760 +  A   - The Jacobian of F(t,U,U_t)
2761 .  B   - The preconditioner matrix, often the same as A
2762 .  f   - The function to compute the matrices
2763 - ctx - User-defined context for Jacobian evaluation routine
2764 
2765    Notes: You can pass in PETSC_NULL for any return argument you do not need.
2766 
2767    Level: advanced
2768 
2769 .seealso: TSGetTimeStep(), TSGetRHSJacobian(), TSGetMatrices(), TSGetTime(), TSGetTimeStepNumber()
2770 
2771 .keywords: TS, timestep, get, matrix, Jacobian
2772 @*/
2773 PetscErrorCode  TSGetIJacobian(TS ts,Mat *A,Mat *B,TSIJacobian *f,void **ctx)
2774 {
2775   PetscErrorCode ierr;
2776   SNES           snes;
2777   DM             dm;
2778 
2779   PetscFunctionBegin;
2780   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2781   ierr = SNESSetUpMatrices(snes);CHKERRQ(ierr);
2782   ierr = SNESGetJacobian(snes,A,B,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
2783   ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
2784   ierr = DMTSGetIJacobian(dm,f,ctx);CHKERRQ(ierr);
2785   PetscFunctionReturn(0);
2786 }
2787 
2788 struct _n_TSMonitorDrawCtx {
2789   PetscViewer viewer;
2790   Vec         initialsolution;
2791   PetscBool   showinitial;
2792   PetscInt    howoften;  /* when > 0 uses step % howoften, when negative only final solution plotted */
2793 };
2794 
2795 #undef __FUNCT__
2796 #define __FUNCT__ "TSMonitorDrawSolution"
2797 /*@C
2798    TSMonitorDrawSolution - Monitors progress of the TS solvers by calling
2799    VecView() for the solution at each timestep
2800 
2801    Collective on TS
2802 
2803    Input Parameters:
2804 +  ts - the TS context
2805 .  step - current time-step
2806 .  ptime - current time
2807 -  dummy - either a viewer or PETSC_NULL
2808 
2809    Options Database:
2810 .   -ts_monitor_draw_solution_initial - show initial solution as well as current solution
2811 
2812    Notes: the initial solution and current solution are not displayed with a common axis scaling so generally the option -ts_monitor_draw_solution_initial
2813        will look bad
2814 
2815    Level: intermediate
2816 
2817 .keywords: TS,  vector, monitor, view
2818 
2819 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
2820 @*/
2821 PetscErrorCode  TSMonitorDrawSolution(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
2822 {
2823   PetscErrorCode   ierr;
2824   TSMonitorDrawCtx ictx = (TSMonitorDrawCtx)dummy;
2825 
2826   PetscFunctionBegin;
2827   if (!step && ictx->showinitial) {
2828     if (!ictx->initialsolution) {
2829       ierr = VecDuplicate(u,&ictx->initialsolution);CHKERRQ(ierr);
2830     }
2831     ierr = VecCopy(u,ictx->initialsolution);CHKERRQ(ierr);
2832   }
2833   if (!(((ictx->howoften > 0) && (!(step % ictx->howoften)) && (step > -1)) || ((ictx->howoften == -1) && (step == -1)))) PetscFunctionReturn(0);
2834 
2835   if (ictx->showinitial) {
2836     PetscReal pause;
2837     ierr = PetscViewerDrawGetPause(ictx->viewer,&pause);CHKERRQ(ierr);
2838     ierr = PetscViewerDrawSetPause(ictx->viewer,0.0);CHKERRQ(ierr);
2839     ierr = VecView(ictx->initialsolution,ictx->viewer);CHKERRQ(ierr);
2840     ierr = PetscViewerDrawSetPause(ictx->viewer,pause);CHKERRQ(ierr);
2841     ierr = PetscViewerDrawSetHold(ictx->viewer,PETSC_TRUE);CHKERRQ(ierr);
2842   }
2843   ierr = VecView(u,ictx->viewer);CHKERRQ(ierr);
2844   if (ictx->showinitial) {
2845     ierr = PetscViewerDrawSetHold(ictx->viewer,PETSC_FALSE);CHKERRQ(ierr);
2846   }
2847   PetscFunctionReturn(0);
2848 }
2849 
2850 
2851 #undef __FUNCT__
2852 #define __FUNCT__ "TSMonitorDrawCtxDestroy"
2853 /*@C
2854    TSMonitorDrawCtxDestroy - Destroys the monitor context for TSMonitorDrawSolution()
2855 
2856    Collective on TS
2857 
2858    Input Parameters:
2859 .    ctx - the monitor context
2860 
2861    Level: intermediate
2862 
2863 .keywords: TS,  vector, monitor, view
2864 
2865 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSMonitorDrawSolution(), TSMonitorDrawError()
2866 @*/
2867 PetscErrorCode  TSMonitorDrawCtxDestroy(TSMonitorDrawCtx *ictx)
2868 {
2869   PetscErrorCode       ierr;
2870 
2871   PetscFunctionBegin;
2872   ierr = PetscViewerDestroy(&(*ictx)->viewer);CHKERRQ(ierr);
2873   ierr = VecDestroy(&(*ictx)->initialsolution);CHKERRQ(ierr);
2874   ierr = PetscFree(*ictx);CHKERRQ(ierr);
2875   PetscFunctionReturn(0);
2876 }
2877 
2878 #undef __FUNCT__
2879 #define __FUNCT__ "TSMonitorDrawCtxCreate"
2880 /*@C
2881    TSMonitorDrawCtxCreate - Creates the monitor context for TSMonitorDrawCtx
2882 
2883    Collective on TS
2884 
2885    Input Parameter:
2886 .    ts - time-step context
2887 
2888    Output Patameter:
2889 .    ctx - the monitor context
2890 
2891    Options Database:
2892 .   -ts_monitor_draw_solution_initial - show initial solution as well as current solution
2893 
2894    Level: intermediate
2895 
2896 .keywords: TS,  vector, monitor, view
2897 
2898 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSMonitorDrawCtx()
2899 @*/
2900 PetscErrorCode  TSMonitorDrawCtxCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscInt howoften,TSMonitorDrawCtx *ctx)
2901 {
2902   PetscErrorCode   ierr;
2903 
2904   PetscFunctionBegin;
2905   ierr = PetscNew(struct _n_TSMonitorDrawCtx,ctx);CHKERRQ(ierr);
2906   ierr = PetscViewerDrawOpen(comm,host,label,x,y,m,n,&(*ctx)->viewer);CHKERRQ(ierr);
2907   (*ctx)->showinitial = PETSC_FALSE;
2908   (*ctx)->howoften    = howoften;
2909   ierr = PetscOptionsGetBool(PETSC_NULL,"-ts_monitor_draw_solution_initial",&(*ctx)->showinitial,PETSC_NULL);CHKERRQ(ierr);
2910   PetscFunctionReturn(0);
2911 }
2912 
2913 #undef __FUNCT__
2914 #define __FUNCT__ "TSMonitorDrawError"
2915 /*@C
2916    TSMonitorDrawError - Monitors progress of the TS solvers by calling
2917    VecView() for the error at each timestep
2918 
2919    Collective on TS
2920 
2921    Input Parameters:
2922 +  ts - the TS context
2923 .  step - current time-step
2924 .  ptime - current time
2925 -  dummy - either a viewer or PETSC_NULL
2926 
2927    Level: intermediate
2928 
2929 .keywords: TS,  vector, monitor, view
2930 
2931 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
2932 @*/
2933 PetscErrorCode  TSMonitorDrawError(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
2934 {
2935   PetscErrorCode   ierr;
2936   TSMonitorDrawCtx ctx = (TSMonitorDrawCtx)dummy;
2937   PetscViewer      viewer = ctx->viewer;
2938   Vec              work;
2939 
2940   PetscFunctionBegin;
2941   if (!(((ctx->howoften > 0) && (!(step % ctx->howoften)) && (step > -1)) || ((ctx->howoften == -1) && (step == -1)))) PetscFunctionReturn(0);
2942   ierr = VecDuplicate(u,&work);CHKERRQ(ierr);
2943   ierr = TSComputeSolutionFunction(ts,ptime,work);CHKERRQ(ierr);
2944   ierr = VecAXPY(work,-1.0,u);CHKERRQ(ierr);
2945   ierr = VecView(work,viewer);CHKERRQ(ierr);
2946   ierr = VecDestroy(&work);CHKERRQ(ierr);
2947   PetscFunctionReturn(0);
2948 }
2949 
2950 #include <petsc-private/dmimpl.h>
2951 #undef __FUNCT__
2952 #define __FUNCT__ "TSSetDM"
2953 /*@
2954    TSSetDM - Sets the DM that may be used by some preconditioners
2955 
2956    Logically Collective on TS and DM
2957 
2958    Input Parameters:
2959 +  ts - the preconditioner context
2960 -  dm - the dm
2961 
2962    Level: intermediate
2963 
2964 
2965 .seealso: TSGetDM(), SNESSetDM(), SNESGetDM()
2966 @*/
2967 PetscErrorCode  TSSetDM(TS ts,DM dm)
2968 {
2969   PetscErrorCode ierr;
2970   SNES           snes;
2971   DMTS           tsdm;
2972 
2973   PetscFunctionBegin;
2974   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
2975   ierr = PetscObjectReference((PetscObject)dm);CHKERRQ(ierr);
2976   if (ts->dm) {               /* Move the DMTS context over to the new DM unless the new DM already has one */
2977     if (ts->dm->dmts && !dm->dmts) {
2978       ierr = DMCopyDMTS(ts->dm,dm);CHKERRQ(ierr);
2979       ierr = DMGetDMTS(ts->dm,&tsdm);CHKERRQ(ierr);
2980       if (tsdm->originaldm == ts->dm) { /* Grant write privileges to the replacement DM */
2981         tsdm->originaldm = dm;
2982       }
2983     }
2984     ierr = DMDestroy(&ts->dm);CHKERRQ(ierr);
2985   }
2986   ts->dm = dm;
2987   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
2988   ierr = SNESSetDM(snes,dm);CHKERRQ(ierr);
2989   PetscFunctionReturn(0);
2990 }
2991 
2992 #undef __FUNCT__
2993 #define __FUNCT__ "TSGetDM"
2994 /*@
2995    TSGetDM - Gets the DM that may be used by some preconditioners
2996 
2997    Not Collective
2998 
2999    Input Parameter:
3000 . ts - the preconditioner context
3001 
3002    Output Parameter:
3003 .  dm - the dm
3004 
3005    Level: intermediate
3006 
3007 
3008 .seealso: TSSetDM(), SNESSetDM(), SNESGetDM()
3009 @*/
3010 PetscErrorCode  TSGetDM(TS ts,DM *dm)
3011 {
3012   PetscErrorCode ierr;
3013 
3014   PetscFunctionBegin;
3015   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3016   if (!ts->dm) {
3017     ierr = DMShellCreate(((PetscObject)ts)->comm,&ts->dm);CHKERRQ(ierr);
3018     if (ts->snes) {ierr = SNESSetDM(ts->snes,ts->dm);CHKERRQ(ierr);}
3019   }
3020   *dm = ts->dm;
3021   PetscFunctionReturn(0);
3022 }
3023 
3024 #undef __FUNCT__
3025 #define __FUNCT__ "SNESTSFormFunction"
3026 /*@
3027    SNESTSFormFunction - Function to evaluate nonlinear residual
3028 
3029    Logically Collective on SNES
3030 
3031    Input Parameter:
3032 + snes - nonlinear solver
3033 . U - the current state at which to evaluate the residual
3034 - ctx - user context, must be a TS
3035 
3036    Output Parameter:
3037 . F - the nonlinear residual
3038 
3039    Notes:
3040    This function is not normally called by users and is automatically registered with the SNES used by TS.
3041    It is most frequently passed to MatFDColoringSetFunction().
3042 
3043    Level: advanced
3044 
3045 .seealso: SNESSetFunction(), MatFDColoringSetFunction()
3046 @*/
3047 PetscErrorCode  SNESTSFormFunction(SNES snes,Vec U,Vec F,void *ctx)
3048 {
3049   TS             ts = (TS)ctx;
3050   PetscErrorCode ierr;
3051 
3052   PetscFunctionBegin;
3053   PetscValidHeaderSpecific(snes,SNES_CLASSID,1);
3054   PetscValidHeaderSpecific(U,VEC_CLASSID,2);
3055   PetscValidHeaderSpecific(F,VEC_CLASSID,3);
3056   PetscValidHeaderSpecific(ts,TS_CLASSID,4);
3057   ierr = (ts->ops->snesfunction)(snes,U,F,ts);CHKERRQ(ierr);
3058   PetscFunctionReturn(0);
3059 }
3060 
3061 #undef __FUNCT__
3062 #define __FUNCT__ "SNESTSFormJacobian"
3063 /*@
3064    SNESTSFormJacobian - Function to evaluate the Jacobian
3065 
3066    Collective on SNES
3067 
3068    Input Parameter:
3069 + snes - nonlinear solver
3070 . U - the current state at which to evaluate the residual
3071 - ctx - user context, must be a TS
3072 
3073    Output Parameter:
3074 + A - the Jacobian
3075 . B - the preconditioning matrix (may be the same as A)
3076 - flag - indicates any structure change in the matrix
3077 
3078    Notes:
3079    This function is not normally called by users and is automatically registered with the SNES used by TS.
3080 
3081    Level: developer
3082 
3083 .seealso: SNESSetJacobian()
3084 @*/
3085 PetscErrorCode  SNESTSFormJacobian(SNES snes,Vec U,Mat *A,Mat *B,MatStructure *flag,void *ctx)
3086 {
3087   TS             ts = (TS)ctx;
3088   PetscErrorCode ierr;
3089 
3090   PetscFunctionBegin;
3091   PetscValidHeaderSpecific(snes,SNES_CLASSID,1);
3092   PetscValidHeaderSpecific(U,VEC_CLASSID,2);
3093   PetscValidPointer(A,3);
3094   PetscValidHeaderSpecific(*A,MAT_CLASSID,3);
3095   PetscValidPointer(B,4);
3096   PetscValidHeaderSpecific(*B,MAT_CLASSID,4);
3097   PetscValidPointer(flag,5);
3098   PetscValidHeaderSpecific(ts,TS_CLASSID,6);
3099   ierr = (ts->ops->snesjacobian)(snes,U,A,B,flag,ts);CHKERRQ(ierr);
3100   PetscFunctionReturn(0);
3101 }
3102 
3103 #undef __FUNCT__
3104 #define __FUNCT__ "TSComputeRHSFunctionLinear"
3105 /*@C
3106    TSComputeRHSFunctionLinear - Evaluate the right hand side via the user-provided Jacobian, for linear problems only
3107 
3108    Collective on TS
3109 
3110    Input Arguments:
3111 +  ts - time stepping context
3112 .  t - time at which to evaluate
3113 .  U - state at which to evaluate
3114 -  ctx - context
3115 
3116    Output Arguments:
3117 .  F - right hand side
3118 
3119    Level: intermediate
3120 
3121    Notes:
3122    This function is intended to be passed to TSSetRHSFunction() to evaluate the right hand side for linear problems.
3123    The matrix (and optionally the evaluation context) should be passed to TSSetRHSJacobian().
3124 
3125 .seealso: TSSetRHSFunction(), TSSetRHSJacobian(), TSComputeRHSJacobianConstant()
3126 @*/
3127 PetscErrorCode TSComputeRHSFunctionLinear(TS ts,PetscReal t,Vec U,Vec F,void *ctx)
3128 {
3129   PetscErrorCode ierr;
3130   Mat            Arhs,Brhs;
3131   MatStructure   flg2;
3132 
3133   PetscFunctionBegin;
3134   ierr = TSGetRHSMats_Private(ts,&Arhs,&Brhs);CHKERRQ(ierr);
3135   ierr = TSComputeRHSJacobian(ts,t,U,&Arhs,&Brhs,&flg2);CHKERRQ(ierr);
3136   ierr = MatMult(Arhs,U,F);CHKERRQ(ierr);
3137   PetscFunctionReturn(0);
3138 }
3139 
3140 #undef __FUNCT__
3141 #define __FUNCT__ "TSComputeRHSJacobianConstant"
3142 /*@C
3143    TSComputeRHSJacobianConstant - Reuses a Jacobian that is time-independent.
3144 
3145    Collective on TS
3146 
3147    Input Arguments:
3148 +  ts - time stepping context
3149 .  t - time at which to evaluate
3150 .  U - state at which to evaluate
3151 -  ctx - context
3152 
3153    Output Arguments:
3154 +  A - pointer to operator
3155 .  B - pointer to preconditioning matrix
3156 -  flg - matrix structure flag
3157 
3158    Level: intermediate
3159 
3160    Notes:
3161    This function is intended to be passed to TSSetRHSJacobian() to evaluate the Jacobian for linear time-independent problems.
3162 
3163 .seealso: TSSetRHSFunction(), TSSetRHSJacobian(), TSComputeRHSFunctionLinear()
3164 @*/
3165 PetscErrorCode TSComputeRHSJacobianConstant(TS ts,PetscReal t,Vec U,Mat *A,Mat *B,MatStructure *flg,void *ctx)
3166 {
3167   PetscFunctionBegin;
3168   *flg = SAME_PRECONDITIONER;
3169   PetscFunctionReturn(0);
3170 }
3171 
3172 #undef __FUNCT__
3173 #define __FUNCT__ "TSComputeIFunctionLinear"
3174 /*@C
3175    TSComputeIFunctionLinear - Evaluate the left hand side via the user-provided Jacobian, for linear problems only
3176 
3177    Collective on TS
3178 
3179    Input Arguments:
3180 +  ts - time stepping context
3181 .  t - time at which to evaluate
3182 .  U - state at which to evaluate
3183 .  Udot - time derivative of state vector
3184 -  ctx - context
3185 
3186    Output Arguments:
3187 .  F - left hand side
3188 
3189    Level: intermediate
3190 
3191    Notes:
3192    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
3193    user is required to write their own TSComputeIFunction.
3194    This function is intended to be passed to TSSetIFunction() to evaluate the left hand side for linear problems.
3195    The matrix (and optionally the evaluation context) should be passed to TSSetIJacobian().
3196 
3197 .seealso: TSSetIFunction(), TSSetIJacobian(), TSComputeIJacobianConstant()
3198 @*/
3199 PetscErrorCode TSComputeIFunctionLinear(TS ts,PetscReal t,Vec U,Vec Udot,Vec F,void *ctx)
3200 {
3201   PetscErrorCode ierr;
3202   Mat            A,B;
3203   MatStructure   flg2;
3204 
3205   PetscFunctionBegin;
3206   ierr = TSGetIJacobian(ts,&A,&B,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
3207   ierr = TSComputeIJacobian(ts,t,U,Udot,1.0,&A,&B,&flg2,PETSC_TRUE);CHKERRQ(ierr);
3208   ierr = MatMult(A,Udot,F);CHKERRQ(ierr);
3209   PetscFunctionReturn(0);
3210 }
3211 
3212 #undef __FUNCT__
3213 #define __FUNCT__ "TSComputeIJacobianConstant"
3214 /*@C
3215    TSComputeIJacobianConstant - Reuses a Jacobian that is time-independent.
3216 
3217    Collective on TS
3218 
3219    Input Arguments:
3220 +  ts - time stepping context
3221 .  t - time at which to evaluate
3222 .  U - state at which to evaluate
3223 .  Udot - time derivative of state vector
3224 .  shift - shift to apply
3225 -  ctx - context
3226 
3227    Output Arguments:
3228 +  A - pointer to operator
3229 .  B - pointer to preconditioning matrix
3230 -  flg - matrix structure flag
3231 
3232    Level: intermediate
3233 
3234    Notes:
3235    This function is intended to be passed to TSSetIJacobian() to evaluate the Jacobian for linear time-independent problems.
3236 
3237 .seealso: TSSetIFunction(), TSSetIJacobian(), TSComputeIFunctionLinear()
3238 @*/
3239 PetscErrorCode TSComputeIJacobianConstant(TS ts,PetscReal t,Vec U,Vec Udot,PetscReal shift,Mat *A,Mat *B,MatStructure *flg,void *ctx)
3240 {
3241   PetscFunctionBegin;
3242   *flg = SAME_PRECONDITIONER;
3243   PetscFunctionReturn(0);
3244 }
3245 
3246 #undef __FUNCT__
3247 #define __FUNCT__ "TSGetConvergedReason"
3248 /*@
3249    TSGetConvergedReason - Gets the reason the TS iteration was stopped.
3250 
3251    Not Collective
3252 
3253    Input Parameter:
3254 .  ts - the TS context
3255 
3256    Output Parameter:
3257 .  reason - negative value indicates diverged, positive value converged, see TSConvergedReason or the
3258             manual pages for the individual convergence tests for complete lists
3259 
3260    Level: beginner
3261 
3262    Notes:
3263    Can only be called after the call to TSSolve() is complete.
3264 
3265 .keywords: TS, nonlinear, set, convergence, test
3266 
3267 .seealso: TSSetConvergenceTest(), TSConvergedReason
3268 @*/
3269 PetscErrorCode  TSGetConvergedReason(TS ts,TSConvergedReason *reason)
3270 {
3271   PetscFunctionBegin;
3272   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3273   PetscValidPointer(reason,2);
3274   *reason = ts->reason;
3275   PetscFunctionReturn(0);
3276 }
3277 
3278 #undef __FUNCT__
3279 #define __FUNCT__ "TSSetConvergedReason"
3280 /*@
3281    TSSetConvergedReason - Sets the reason for handling the convergence of TSSolve.
3282 
3283    Not Collective
3284 
3285    Input Parameter:
3286 +  ts - the TS context
3287 .  reason - negative value indicates diverged, positive value converged, see TSConvergedReason or the
3288             manual pages for the individual convergence tests for complete lists
3289 
3290    Level: advanced
3291 
3292    Notes:
3293    Can only be called during TSSolve() is active.
3294 
3295 .keywords: TS, nonlinear, set, convergence, test
3296 
3297 .seealso: TSConvergedReason
3298 @*/
3299 PetscErrorCode  TSSetConvergedReason(TS ts,TSConvergedReason reason)
3300 {
3301   PetscFunctionBegin;
3302   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3303   ts->reason = reason;
3304   PetscFunctionReturn(0);
3305 }
3306 
3307 #undef __FUNCT__
3308 #define __FUNCT__ "TSGetSolveTime"
3309 /*@
3310    TSGetSolveTime - Gets the time after a call to TSSolve()
3311 
3312    Not Collective
3313 
3314    Input Parameter:
3315 .  ts - the TS context
3316 
3317    Output Parameter:
3318 .  ftime - the final time. This time should correspond to the final time set with TSSetDuration()
3319 
3320    Level: beginner
3321 
3322    Notes:
3323    Can only be called after the call to TSSolve() is complete.
3324 
3325 .keywords: TS, nonlinear, set, convergence, test
3326 
3327 .seealso: TSSetConvergenceTest(), TSConvergedReason
3328 @*/
3329 PetscErrorCode  TSGetSolveTime(TS ts,PetscReal *ftime)
3330 {
3331   PetscFunctionBegin;
3332   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3333   PetscValidPointer(ftime,2);
3334   *ftime = ts->solvetime;
3335   PetscFunctionReturn(0);
3336 }
3337 
3338 #undef __FUNCT__
3339 #define __FUNCT__ "TSGetSNESIterations"
3340 /*@
3341    TSGetSNESIterations - Gets the total number of nonlinear iterations
3342    used by the time integrator.
3343 
3344    Not Collective
3345 
3346    Input Parameter:
3347 .  ts - TS context
3348 
3349    Output Parameter:
3350 .  nits - number of nonlinear iterations
3351 
3352    Notes:
3353    This counter is reset to zero for each successive call to TSSolve().
3354 
3355    Level: intermediate
3356 
3357 .keywords: TS, get, number, nonlinear, iterations
3358 
3359 .seealso:  TSGetKSPIterations()
3360 @*/
3361 PetscErrorCode TSGetSNESIterations(TS ts,PetscInt *nits)
3362 {
3363   PetscFunctionBegin;
3364   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3365   PetscValidIntPointer(nits,2);
3366   *nits = ts->snes_its;
3367   PetscFunctionReturn(0);
3368 }
3369 
3370 #undef __FUNCT__
3371 #define __FUNCT__ "TSGetKSPIterations"
3372 /*@
3373    TSGetKSPIterations - Gets the total number of linear iterations
3374    used by the time integrator.
3375 
3376    Not Collective
3377 
3378    Input Parameter:
3379 .  ts - TS context
3380 
3381    Output Parameter:
3382 .  lits - number of linear iterations
3383 
3384    Notes:
3385    This counter is reset to zero for each successive call to TSSolve().
3386 
3387    Level: intermediate
3388 
3389 .keywords: TS, get, number, linear, iterations
3390 
3391 .seealso:  TSGetSNESIterations(), SNESGetKSPIterations()
3392 @*/
3393 PetscErrorCode TSGetKSPIterations(TS ts,PetscInt *lits)
3394 {
3395   PetscFunctionBegin;
3396   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3397   PetscValidIntPointer(lits,2);
3398   *lits = ts->ksp_its;
3399   PetscFunctionReturn(0);
3400 }
3401 
3402 #undef __FUNCT__
3403 #define __FUNCT__ "TSGetStepRejections"
3404 /*@
3405    TSGetStepRejections - Gets the total number of rejected steps.
3406 
3407    Not Collective
3408 
3409    Input Parameter:
3410 .  ts - TS context
3411 
3412    Output Parameter:
3413 .  rejects - number of steps rejected
3414 
3415    Notes:
3416    This counter is reset to zero for each successive call to TSSolve().
3417 
3418    Level: intermediate
3419 
3420 .keywords: TS, get, number
3421 
3422 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetSNESFailures(), TSSetMaxSNESFailures(), TSSetErrorIfStepFails()
3423 @*/
3424 PetscErrorCode TSGetStepRejections(TS ts,PetscInt *rejects)
3425 {
3426   PetscFunctionBegin;
3427   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3428   PetscValidIntPointer(rejects,2);
3429   *rejects = ts->reject;
3430   PetscFunctionReturn(0);
3431 }
3432 
3433 #undef __FUNCT__
3434 #define __FUNCT__ "TSGetSNESFailures"
3435 /*@
3436    TSGetSNESFailures - Gets the total number of failed SNES solves
3437 
3438    Not Collective
3439 
3440    Input Parameter:
3441 .  ts - TS context
3442 
3443    Output Parameter:
3444 .  fails - number of failed nonlinear solves
3445 
3446    Notes:
3447    This counter is reset to zero for each successive call to TSSolve().
3448 
3449    Level: intermediate
3450 
3451 .keywords: TS, get, number
3452 
3453 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSSetMaxSNESFailures()
3454 @*/
3455 PetscErrorCode TSGetSNESFailures(TS ts,PetscInt *fails)
3456 {
3457   PetscFunctionBegin;
3458   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3459   PetscValidIntPointer(fails,2);
3460   *fails = ts->num_snes_failures;
3461   PetscFunctionReturn(0);
3462 }
3463 
3464 #undef __FUNCT__
3465 #define __FUNCT__ "TSSetMaxStepRejections"
3466 /*@
3467    TSSetMaxStepRejections - Sets the maximum number of step rejections before a step fails
3468 
3469    Not Collective
3470 
3471    Input Parameter:
3472 +  ts - TS context
3473 -  rejects - maximum number of rejected steps, pass -1 for unlimited
3474 
3475    Notes:
3476    The counter is reset to zero for each step
3477 
3478    Options Database Key:
3479  .  -ts_max_reject - Maximum number of step rejections before a step fails
3480 
3481    Level: intermediate
3482 
3483 .keywords: TS, set, maximum, number
3484 
3485 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxSNESFailures(), TSGetStepRejections(), TSGetSNESFailures(), TSSetErrorIfStepFails(), TSGetConvergedReason()
3486 @*/
3487 PetscErrorCode TSSetMaxStepRejections(TS ts,PetscInt rejects)
3488 {
3489   PetscFunctionBegin;
3490   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3491   ts->max_reject = rejects;
3492   PetscFunctionReturn(0);
3493 }
3494 
3495 #undef __FUNCT__
3496 #define __FUNCT__ "TSSetMaxSNESFailures"
3497 /*@
3498    TSSetMaxSNESFailures - Sets the maximum number of failed SNES solves
3499 
3500    Not Collective
3501 
3502    Input Parameter:
3503 +  ts - TS context
3504 -  fails - maximum number of failed nonlinear solves, pass -1 for unlimited
3505 
3506    Notes:
3507    The counter is reset to zero for each successive call to TSSolve().
3508 
3509    Options Database Key:
3510  .  -ts_max_snes_failures - Maximum number of nonlinear solve failures
3511 
3512    Level: intermediate
3513 
3514 .keywords: TS, set, maximum, number
3515 
3516 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSGetSNESFailures(), SNESGetConvergedReason(), TSGetConvergedReason()
3517 @*/
3518 PetscErrorCode TSSetMaxSNESFailures(TS ts,PetscInt fails)
3519 {
3520   PetscFunctionBegin;
3521   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3522   ts->max_snes_failures = fails;
3523   PetscFunctionReturn(0);
3524 }
3525 
3526 #undef __FUNCT__
3527 #define __FUNCT__ "TSSetErrorIfStepFails()"
3528 /*@
3529    TSSetErrorIfStepFails - Error if no step succeeds
3530 
3531    Not Collective
3532 
3533    Input Parameter:
3534 +  ts - TS context
3535 -  err - PETSC_TRUE to error if no step succeeds, PETSC_FALSE to return without failure
3536 
3537    Options Database Key:
3538  .  -ts_error_if_step_fails - Error if no step succeeds
3539 
3540    Level: intermediate
3541 
3542 .keywords: TS, set, error
3543 
3544 .seealso:  TSGetSNESIterations(), TSGetKSPIterations(), TSSetMaxStepRejections(), TSGetStepRejections(), TSGetSNESFailures(), TSSetErrorIfStepFails(), TSGetConvergedReason()
3545 @*/
3546 PetscErrorCode TSSetErrorIfStepFails(TS ts,PetscBool err)
3547 {
3548   PetscFunctionBegin;
3549   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3550   ts->errorifstepfailed = err;
3551   PetscFunctionReturn(0);
3552 }
3553 
3554 #undef __FUNCT__
3555 #define __FUNCT__ "TSMonitorSolutionBinary"
3556 /*@C
3557    TSMonitorSolutionBinary - Monitors progress of the TS solvers by VecView() for the solution at each timestep. Normally the viewer is a binary file
3558 
3559    Collective on TS
3560 
3561    Input Parameters:
3562 +  ts - the TS context
3563 .  step - current time-step
3564 .  ptime - current time
3565 .  u - current state
3566 -  viewer - binary viewer
3567 
3568    Level: intermediate
3569 
3570 .keywords: TS,  vector, monitor, view
3571 
3572 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3573 @*/
3574 PetscErrorCode  TSMonitorSolutionBinary(TS ts,PetscInt step,PetscReal ptime,Vec u,void *viewer)
3575 {
3576   PetscErrorCode ierr;
3577   PetscViewer    v = (PetscViewer)viewer;
3578 
3579   PetscFunctionBegin;
3580   ierr = VecView(u,v);CHKERRQ(ierr);
3581   PetscFunctionReturn(0);
3582 }
3583 
3584 #undef __FUNCT__
3585 #define __FUNCT__ "TSMonitorSolutionVTK"
3586 /*@C
3587    TSMonitorSolutionVTK - Monitors progress of the TS solvers by VecView() for the solution at each timestep.
3588 
3589    Collective on TS
3590 
3591    Input Parameters:
3592 +  ts - the TS context
3593 .  step - current time-step
3594 .  ptime - current time
3595 .  u - current state
3596 -  filenametemplate - string containing a format specifier for the integer time step (e.g. %03D)
3597 
3598    Level: intermediate
3599 
3600    Notes:
3601    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.
3602    These are named according to the file name template.
3603 
3604    This function is normally passed as an argument to TSMonitorSet() along with TSMonitorSolutionVTKDestroy().
3605 
3606 .keywords: TS,  vector, monitor, view
3607 
3608 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
3609 @*/
3610 PetscErrorCode TSMonitorSolutionVTK(TS ts,PetscInt step,PetscReal ptime,Vec u,void *filenametemplate)
3611 {
3612   PetscErrorCode ierr;
3613   char           filename[PETSC_MAX_PATH_LEN];
3614   PetscViewer    viewer;
3615 
3616   PetscFunctionBegin;
3617   ierr = PetscSNPrintf(filename,sizeof(filename),(const char*)filenametemplate,step);CHKERRQ(ierr);
3618   ierr = PetscViewerVTKOpen(((PetscObject)ts)->comm,filename,FILE_MODE_WRITE,&viewer);CHKERRQ(ierr);
3619   ierr = VecView(u,viewer);CHKERRQ(ierr);
3620   ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
3621   PetscFunctionReturn(0);
3622 }
3623 
3624 #undef __FUNCT__
3625 #define __FUNCT__ "TSMonitorSolutionVTKDestroy"
3626 /*@C
3627    TSMonitorSolutionVTKDestroy - Destroy context for monitoring
3628 
3629    Collective on TS
3630 
3631    Input Parameters:
3632 .  filenametemplate - string containing a format specifier for the integer time step (e.g. %03D)
3633 
3634    Level: intermediate
3635 
3636    Note:
3637    This function is normally passed to TSMonitorSet() along with TSMonitorSolutionVTK().
3638 
3639 .keywords: TS,  vector, monitor, view
3640 
3641 .seealso: TSMonitorSet(), TSMonitorSolutionVTK()
3642 @*/
3643 PetscErrorCode TSMonitorSolutionVTKDestroy(void *filenametemplate)
3644 {
3645   PetscErrorCode ierr;
3646 
3647   PetscFunctionBegin;
3648   ierr = PetscFree(*(char**)filenametemplate);CHKERRQ(ierr);
3649   PetscFunctionReturn(0);
3650 }
3651 
3652 #undef __FUNCT__
3653 #define __FUNCT__ "TSGetTSAdapt"
3654 /*@
3655    TSGetTSAdapt - Get the adaptive controller context for the current method
3656 
3657    Collective on TS if controller has not been created yet
3658 
3659    Input Arguments:
3660 .  ts - time stepping context
3661 
3662    Output Arguments:
3663 .  adapt - adaptive controller
3664 
3665    Level: intermediate
3666 
3667 .seealso: TSAdapt, TSAdaptSetType(), TSAdaptChoose()
3668 @*/
3669 PetscErrorCode TSGetTSAdapt(TS ts,TSAdapt *adapt)
3670 {
3671   PetscErrorCode ierr;
3672 
3673   PetscFunctionBegin;
3674   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3675   PetscValidPointer(adapt,2);
3676   if (!ts->adapt) {
3677     ierr = TSAdaptCreate(((PetscObject)ts)->comm,&ts->adapt);CHKERRQ(ierr);
3678     ierr = PetscLogObjectParent(ts,ts->adapt);CHKERRQ(ierr);
3679     ierr = PetscObjectIncrementTabLevel((PetscObject)ts->adapt,(PetscObject)ts,1);CHKERRQ(ierr);
3680   }
3681   *adapt = ts->adapt;
3682   PetscFunctionReturn(0);
3683 }
3684 
3685 #undef __FUNCT__
3686 #define __FUNCT__ "TSSetTolerances"
3687 /*@
3688    TSSetTolerances - Set tolerances for local truncation error when using adaptive controller
3689 
3690    Logically Collective
3691 
3692    Input Arguments:
3693 +  ts - time integration context
3694 .  atol - scalar absolute tolerances, PETSC_DECIDE to leave current value
3695 .  vatol - vector of absolute tolerances or PETSC_NULL, used in preference to atol if present
3696 .  rtol - scalar relative tolerances, PETSC_DECIDE to leave current value
3697 -  vrtol - vector of relative tolerances or PETSC_NULL, used in preference to atol if present
3698 
3699    Level: beginner
3700 
3701 .seealso: TS, TSAdapt, TSVecNormWRMS(), TSGetTolerances()
3702 @*/
3703 PetscErrorCode TSSetTolerances(TS ts,PetscReal atol,Vec vatol,PetscReal rtol,Vec vrtol)
3704 {
3705   PetscErrorCode ierr;
3706 
3707   PetscFunctionBegin;
3708   if (atol != PETSC_DECIDE && atol != PETSC_DEFAULT) ts->atol = atol;
3709   if (vatol) {
3710     ierr = PetscObjectReference((PetscObject)vatol);CHKERRQ(ierr);
3711     ierr = VecDestroy(&ts->vatol);CHKERRQ(ierr);
3712     ts->vatol = vatol;
3713   }
3714   if (rtol != PETSC_DECIDE && rtol != PETSC_DEFAULT) ts->rtol = rtol;
3715   if (vrtol) {
3716     ierr = PetscObjectReference((PetscObject)vrtol);CHKERRQ(ierr);
3717     ierr = VecDestroy(&ts->vrtol);CHKERRQ(ierr);
3718     ts->vrtol = vrtol;
3719   }
3720   PetscFunctionReturn(0);
3721 }
3722 
3723 #undef __FUNCT__
3724 #define __FUNCT__ "TSGetTolerances"
3725 /*@
3726    TSGetTolerances - Get tolerances for local truncation error when using adaptive controller
3727 
3728    Logically Collective
3729 
3730    Input Arguments:
3731 .  ts - time integration context
3732 
3733    Output Arguments:
3734 +  atol - scalar absolute tolerances, PETSC_NULL to ignore
3735 .  vatol - vector of absolute tolerances, PETSC_NULL to ignore
3736 .  rtol - scalar relative tolerances, PETSC_NULL to ignore
3737 -  vrtol - vector of relative tolerances, PETSC_NULL to ignore
3738 
3739    Level: beginner
3740 
3741 .seealso: TS, TSAdapt, TSVecNormWRMS(), TSSetTolerances()
3742 @*/
3743 PetscErrorCode TSGetTolerances(TS ts,PetscReal *atol,Vec *vatol,PetscReal *rtol,Vec *vrtol)
3744 {
3745   PetscFunctionBegin;
3746   if (atol)  *atol  = ts->atol;
3747   if (vatol) *vatol = ts->vatol;
3748   if (rtol)  *rtol  = ts->rtol;
3749   if (vrtol) *vrtol = ts->vrtol;
3750   PetscFunctionReturn(0);
3751 }
3752 
3753 #undef __FUNCT__
3754 #define __FUNCT__ "TSErrorNormWRMS"
3755 /*@
3756    TSErrorNormWRMS - compute a weighted norm of the difference between a vector and the current state
3757 
3758    Collective on TS
3759 
3760    Input Arguments:
3761 +  ts - time stepping context
3762 -  Y - state vector to be compared to ts->vec_sol
3763 
3764    Output Arguments:
3765 .  norm - weighted norm, a value of 1.0 is considered small
3766 
3767    Level: developer
3768 
3769 .seealso: TSSetTolerances()
3770 @*/
3771 PetscErrorCode TSErrorNormWRMS(TS ts,Vec Y,PetscReal *norm)
3772 {
3773   PetscErrorCode    ierr;
3774   PetscInt          i,n,N;
3775   const PetscScalar *u,*y;
3776   Vec               U;
3777   PetscReal         sum,gsum;
3778 
3779   PetscFunctionBegin;
3780   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3781   PetscValidHeaderSpecific(Y,VEC_CLASSID,2);
3782   PetscValidPointer(norm,3);
3783   U = ts->vec_sol;
3784   PetscCheckSameTypeAndComm(U,1,Y,2);
3785   if (U == Y) SETERRQ(((PetscObject)U)->comm,PETSC_ERR_ARG_IDN,"Y cannot be the TS solution vector");
3786 
3787   ierr = VecGetSize(U,&N);CHKERRQ(ierr);
3788   ierr = VecGetLocalSize(U,&n);CHKERRQ(ierr);
3789   ierr = VecGetArrayRead(U,&u);CHKERRQ(ierr);
3790   ierr = VecGetArrayRead(Y,&y);CHKERRQ(ierr);
3791   sum = 0.;
3792   if (ts->vatol && ts->vrtol) {
3793     const PetscScalar *atol,*rtol;
3794     ierr = VecGetArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
3795     ierr = VecGetArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
3796     for (i=0; i<n; i++) {
3797       PetscReal tol = PetscRealPart(atol[i]) + PetscRealPart(rtol[i]) * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
3798       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
3799     }
3800     ierr = VecRestoreArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
3801     ierr = VecRestoreArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
3802   } else if (ts->vatol) {       /* vector atol, scalar rtol */
3803     const PetscScalar *atol;
3804     ierr = VecGetArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
3805     for (i=0; i<n; i++) {
3806       PetscReal tol = PetscRealPart(atol[i]) + ts->rtol * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
3807       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
3808     }
3809     ierr = VecRestoreArrayRead(ts->vatol,&atol);CHKERRQ(ierr);
3810   } else if (ts->vrtol) {       /* scalar atol, vector rtol */
3811     const PetscScalar *rtol;
3812     ierr = VecGetArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
3813     for (i=0; i<n; i++) {
3814       PetscReal tol = ts->atol + PetscRealPart(rtol[i]) * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
3815       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
3816     }
3817     ierr = VecRestoreArrayRead(ts->vrtol,&rtol);CHKERRQ(ierr);
3818   } else {                      /* scalar atol, scalar rtol */
3819     for (i=0; i<n; i++) {
3820       PetscReal tol = ts->atol + ts->rtol * PetscMax(PetscAbsScalar(u[i]),PetscAbsScalar(y[i]));
3821       sum += PetscSqr(PetscAbsScalar(y[i] - u[i]) / tol);
3822     }
3823   }
3824   ierr = VecRestoreArrayRead(U,&u);CHKERRQ(ierr);
3825   ierr = VecRestoreArrayRead(Y,&y);CHKERRQ(ierr);
3826 
3827   ierr = MPI_Allreduce(&sum,&gsum,1,MPIU_REAL,MPIU_SUM,((PetscObject)ts)->comm);CHKERRQ(ierr);
3828   *norm = PetscSqrtReal(gsum / N);
3829   if (PetscIsInfOrNanScalar(*norm)) SETERRQ(((PetscObject)ts)->comm,PETSC_ERR_FP,"Infinite or not-a-number generated in norm");
3830   PetscFunctionReturn(0);
3831 }
3832 
3833 #undef __FUNCT__
3834 #define __FUNCT__ "TSSetCFLTimeLocal"
3835 /*@
3836    TSSetCFLTimeLocal - Set the local CFL constraint relative to forward Euler
3837 
3838    Logically Collective on TS
3839 
3840    Input Arguments:
3841 +  ts - time stepping context
3842 -  cfltime - maximum stable time step if using forward Euler (value can be different on each process)
3843 
3844    Note:
3845    After calling this function, the global CFL time can be obtained by calling TSGetCFLTime()
3846 
3847    Level: intermediate
3848 
3849 .seealso: TSGetCFLTime(), TSADAPTCFL
3850 @*/
3851 PetscErrorCode TSSetCFLTimeLocal(TS ts,PetscReal cfltime)
3852 {
3853   PetscFunctionBegin;
3854   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
3855   ts->cfltime_local = cfltime;
3856   ts->cfltime = -1.;
3857   PetscFunctionReturn(0);
3858 }
3859 
3860 #undef __FUNCT__
3861 #define __FUNCT__ "TSGetCFLTime"
3862 /*@
3863    TSGetCFLTime - Get the maximum stable time step according to CFL criteria applied to forward Euler
3864 
3865    Collective on TS
3866 
3867    Input Arguments:
3868 .  ts - time stepping context
3869 
3870    Output Arguments:
3871 .  cfltime - maximum stable time step for forward Euler
3872 
3873    Level: advanced
3874 
3875 .seealso: TSSetCFLTimeLocal()
3876 @*/
3877 PetscErrorCode TSGetCFLTime(TS ts,PetscReal *cfltime)
3878 {
3879   PetscErrorCode ierr;
3880 
3881   PetscFunctionBegin;
3882   if (ts->cfltime < 0) {
3883     ierr = MPI_Allreduce(&ts->cfltime_local,&ts->cfltime,1,MPIU_REAL,MPIU_MIN,((PetscObject)ts)->comm);CHKERRQ(ierr);
3884   }
3885   *cfltime = ts->cfltime;
3886   PetscFunctionReturn(0);
3887 }
3888 
3889 #undef __FUNCT__
3890 #define __FUNCT__ "TSVISetVariableBounds"
3891 /*@
3892    TSVISetVariableBounds - Sets the lower and upper bounds for the solution vector. xl <= x <= xu
3893 
3894    Input Parameters:
3895 .  ts   - the TS context.
3896 .  xl   - lower bound.
3897 .  xu   - upper bound.
3898 
3899    Notes:
3900    If this routine is not called then the lower and upper bounds are set to
3901    SNES_VI_NINF and SNES_VI_INF respectively during SNESSetUp().
3902 
3903    Level: advanced
3904 
3905 @*/
3906 PetscErrorCode TSVISetVariableBounds(TS ts, Vec xl, Vec xu)
3907 {
3908   PetscErrorCode ierr;
3909   SNES           snes;
3910 
3911   PetscFunctionBegin;
3912   ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
3913   ierr = SNESVISetVariableBounds(snes,xl,xu);CHKERRQ(ierr);
3914   PetscFunctionReturn(0);
3915 }
3916 
3917 #if defined(PETSC_HAVE_MATLAB_ENGINE)
3918 #include <mex.h>
3919 
3920 typedef struct {char *funcname; mxArray *ctx;} TSMatlabContext;
3921 
3922 #undef __FUNCT__
3923 #define __FUNCT__ "TSComputeFunction_Matlab"
3924 /*
3925    TSComputeFunction_Matlab - Calls the function that has been set with
3926                          TSSetFunctionMatlab().
3927 
3928    Collective on TS
3929 
3930    Input Parameters:
3931 +  snes - the TS context
3932 -  u - input vector
3933 
3934    Output Parameter:
3935 .  y - function vector, as set by TSSetFunction()
3936 
3937    Notes:
3938    TSComputeFunction() is typically used within nonlinear solvers
3939    implementations, so most users would not generally call this routine
3940    themselves.
3941 
3942    Level: developer
3943 
3944 .keywords: TS, nonlinear, compute, function
3945 
3946 .seealso: TSSetFunction(), TSGetFunction()
3947 */
3948 PetscErrorCode  TSComputeFunction_Matlab(TS snes,PetscReal time,Vec u,Vec udot,Vec y, void *ctx)
3949 {
3950   PetscErrorCode   ierr;
3951   TSMatlabContext *sctx = (TSMatlabContext *)ctx;
3952   int              nlhs = 1,nrhs = 7;
3953   mxArray          *plhs[1],*prhs[7];
3954   long long int    lx = 0,lxdot = 0,ly = 0,ls = 0;
3955 
3956   PetscFunctionBegin;
3957   PetscValidHeaderSpecific(snes,TS_CLASSID,1);
3958   PetscValidHeaderSpecific(u,VEC_CLASSID,3);
3959   PetscValidHeaderSpecific(udot,VEC_CLASSID,4);
3960   PetscValidHeaderSpecific(y,VEC_CLASSID,5);
3961   PetscCheckSameComm(snes,1,u,3);
3962   PetscCheckSameComm(snes,1,y,5);
3963 
3964   ierr = PetscMemcpy(&ls,&snes,sizeof(snes));CHKERRQ(ierr);
3965   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
3966   ierr = PetscMemcpy(&lxdot,&udot,sizeof(udot));CHKERRQ(ierr);
3967   ierr = PetscMemcpy(&ly,&y,sizeof(u));CHKERRQ(ierr);
3968   prhs[0] =  mxCreateDoubleScalar((double)ls);
3969   prhs[1] =  mxCreateDoubleScalar(time);
3970   prhs[2] =  mxCreateDoubleScalar((double)lx);
3971   prhs[3] =  mxCreateDoubleScalar((double)lxdot);
3972   prhs[4] =  mxCreateDoubleScalar((double)ly);
3973   prhs[5] =  mxCreateString(sctx->funcname);
3974   prhs[6] =  sctx->ctx;
3975   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSComputeFunctionInternal");CHKERRQ(ierr);
3976   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
3977   mxDestroyArray(prhs[0]);
3978   mxDestroyArray(prhs[1]);
3979   mxDestroyArray(prhs[2]);
3980   mxDestroyArray(prhs[3]);
3981   mxDestroyArray(prhs[4]);
3982   mxDestroyArray(prhs[5]);
3983   mxDestroyArray(plhs[0]);
3984   PetscFunctionReturn(0);
3985 }
3986 
3987 
3988 #undef __FUNCT__
3989 #define __FUNCT__ "TSSetFunctionMatlab"
3990 /*
3991    TSSetFunctionMatlab - Sets the function evaluation routine and function
3992    vector for use by the TS routines in solving ODEs
3993    equations from MATLAB. Here the function is a string containing the name of a MATLAB function
3994 
3995    Logically Collective on TS
3996 
3997    Input Parameters:
3998 +  ts - the TS context
3999 -  func - function evaluation routine
4000 
4001    Calling sequence of func:
4002 $    func (TS ts,PetscReal time,Vec u,Vec udot,Vec f,void *ctx);
4003 
4004    Level: beginner
4005 
4006 .keywords: TS, nonlinear, set, function
4007 
4008 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4009 */
4010 PetscErrorCode  TSSetFunctionMatlab(TS ts,const char *func,mxArray *ctx)
4011 {
4012   PetscErrorCode  ierr;
4013   TSMatlabContext *sctx;
4014 
4015   PetscFunctionBegin;
4016   /* currently sctx is memory bleed */
4017   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4018   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4019   /*
4020      This should work, but it doesn't
4021   sctx->ctx = ctx;
4022   mexMakeArrayPersistent(sctx->ctx);
4023   */
4024   sctx->ctx = mxDuplicateArray(ctx);
4025   ierr = TSSetIFunction(ts,PETSC_NULL,TSComputeFunction_Matlab,sctx);CHKERRQ(ierr);
4026   PetscFunctionReturn(0);
4027 }
4028 
4029 #undef __FUNCT__
4030 #define __FUNCT__ "TSComputeJacobian_Matlab"
4031 /*
4032    TSComputeJacobian_Matlab - Calls the function that has been set with
4033                          TSSetJacobianMatlab().
4034 
4035    Collective on TS
4036 
4037    Input Parameters:
4038 +  ts - the TS context
4039 .  u - input vector
4040 .  A, B - the matrices
4041 -  ctx - user context
4042 
4043    Output Parameter:
4044 .  flag - structure of the matrix
4045 
4046    Level: developer
4047 
4048 .keywords: TS, nonlinear, compute, function
4049 
4050 .seealso: TSSetFunction(), TSGetFunction()
4051 @*/
4052 PetscErrorCode  TSComputeJacobian_Matlab(TS ts,PetscReal time,Vec u,Vec udot,PetscReal shift,Mat *A,Mat *B,MatStructure *flag, void *ctx)
4053 {
4054   PetscErrorCode  ierr;
4055   TSMatlabContext *sctx = (TSMatlabContext *)ctx;
4056   int             nlhs = 2,nrhs = 9;
4057   mxArray         *plhs[2],*prhs[9];
4058   long long int   lx = 0,lxdot = 0,lA = 0,ls = 0, lB = 0;
4059 
4060   PetscFunctionBegin;
4061   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4062   PetscValidHeaderSpecific(u,VEC_CLASSID,3);
4063 
4064   /* call Matlab function in ctx with arguments u and y */
4065 
4066   ierr = PetscMemcpy(&ls,&ts,sizeof(ts));CHKERRQ(ierr);
4067   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4068   ierr = PetscMemcpy(&lxdot,&udot,sizeof(u));CHKERRQ(ierr);
4069   ierr = PetscMemcpy(&lA,A,sizeof(u));CHKERRQ(ierr);
4070   ierr = PetscMemcpy(&lB,B,sizeof(u));CHKERRQ(ierr);
4071   prhs[0] =  mxCreateDoubleScalar((double)ls);
4072   prhs[1] =  mxCreateDoubleScalar((double)time);
4073   prhs[2] =  mxCreateDoubleScalar((double)lx);
4074   prhs[3] =  mxCreateDoubleScalar((double)lxdot);
4075   prhs[4] =  mxCreateDoubleScalar((double)shift);
4076   prhs[5] =  mxCreateDoubleScalar((double)lA);
4077   prhs[6] =  mxCreateDoubleScalar((double)lB);
4078   prhs[7] =  mxCreateString(sctx->funcname);
4079   prhs[8] =  sctx->ctx;
4080   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSComputeJacobianInternal");CHKERRQ(ierr);
4081   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4082   *flag   =  (MatStructure) mxGetScalar(plhs[1]);CHKERRQ(ierr);
4083   mxDestroyArray(prhs[0]);
4084   mxDestroyArray(prhs[1]);
4085   mxDestroyArray(prhs[2]);
4086   mxDestroyArray(prhs[3]);
4087   mxDestroyArray(prhs[4]);
4088   mxDestroyArray(prhs[5]);
4089   mxDestroyArray(prhs[6]);
4090   mxDestroyArray(prhs[7]);
4091   mxDestroyArray(plhs[0]);
4092   mxDestroyArray(plhs[1]);
4093   PetscFunctionReturn(0);
4094 }
4095 
4096 
4097 #undef __FUNCT__
4098 #define __FUNCT__ "TSSetJacobianMatlab"
4099 /*
4100    TSSetJacobianMatlab - Sets the Jacobian function evaluation routine and two empty Jacobian matrices
4101    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
4102 
4103    Logically Collective on TS
4104 
4105    Input Parameters:
4106 +  ts - the TS context
4107 .  A,B - Jacobian matrices
4108 .  func - function evaluation routine
4109 -  ctx - user context
4110 
4111    Calling sequence of func:
4112 $    flag = func (TS ts,PetscReal time,Vec u,Vec udot,Mat A,Mat B,void *ctx);
4113 
4114 
4115    Level: developer
4116 
4117 .keywords: TS, nonlinear, set, function
4118 
4119 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4120 */
4121 PetscErrorCode  TSSetJacobianMatlab(TS ts,Mat A,Mat B,const char *func,mxArray *ctx)
4122 {
4123   PetscErrorCode    ierr;
4124   TSMatlabContext *sctx;
4125 
4126   PetscFunctionBegin;
4127   /* currently sctx is memory bleed */
4128   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4129   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4130   /*
4131      This should work, but it doesn't
4132   sctx->ctx = ctx;
4133   mexMakeArrayPersistent(sctx->ctx);
4134   */
4135   sctx->ctx = mxDuplicateArray(ctx);
4136   ierr = TSSetIJacobian(ts,A,B,TSComputeJacobian_Matlab,sctx);CHKERRQ(ierr);
4137   PetscFunctionReturn(0);
4138 }
4139 
4140 #undef __FUNCT__
4141 #define __FUNCT__ "TSMonitor_Matlab"
4142 /*
4143    TSMonitor_Matlab - Calls the function that has been set with TSMonitorSetMatlab().
4144 
4145    Collective on TS
4146 
4147 .seealso: TSSetFunction(), TSGetFunction()
4148 @*/
4149 PetscErrorCode  TSMonitor_Matlab(TS ts,PetscInt it, PetscReal time,Vec u, void *ctx)
4150 {
4151   PetscErrorCode  ierr;
4152   TSMatlabContext *sctx = (TSMatlabContext *)ctx;
4153   int             nlhs = 1,nrhs = 6;
4154   mxArray         *plhs[1],*prhs[6];
4155   long long int   lx = 0,ls = 0;
4156 
4157   PetscFunctionBegin;
4158   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4159   PetscValidHeaderSpecific(u,VEC_CLASSID,4);
4160 
4161   ierr = PetscMemcpy(&ls,&ts,sizeof(ts));CHKERRQ(ierr);
4162   ierr = PetscMemcpy(&lx,&u,sizeof(u));CHKERRQ(ierr);
4163   prhs[0] =  mxCreateDoubleScalar((double)ls);
4164   prhs[1] =  mxCreateDoubleScalar((double)it);
4165   prhs[2] =  mxCreateDoubleScalar((double)time);
4166   prhs[3] =  mxCreateDoubleScalar((double)lx);
4167   prhs[4] =  mxCreateString(sctx->funcname);
4168   prhs[5] =  sctx->ctx;
4169   ierr    =  mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscTSMonitorInternal");CHKERRQ(ierr);
4170   ierr    =  mxGetScalar(plhs[0]);CHKERRQ(ierr);
4171   mxDestroyArray(prhs[0]);
4172   mxDestroyArray(prhs[1]);
4173   mxDestroyArray(prhs[2]);
4174   mxDestroyArray(prhs[3]);
4175   mxDestroyArray(prhs[4]);
4176   mxDestroyArray(plhs[0]);
4177   PetscFunctionReturn(0);
4178 }
4179 
4180 
4181 #undef __FUNCT__
4182 #define __FUNCT__ "TSMonitorSetMatlab"
4183 /*
4184    TSMonitorSetMatlab - Sets the monitor function from Matlab
4185 
4186    Level: developer
4187 
4188 .keywords: TS, nonlinear, set, function
4189 
4190 .seealso: TSGetFunction(), TSComputeFunction(), TSSetJacobian(), TSSetFunction()
4191 */
4192 PetscErrorCode  TSMonitorSetMatlab(TS ts,const char *func,mxArray *ctx)
4193 {
4194   PetscErrorCode    ierr;
4195   TSMatlabContext *sctx;
4196 
4197   PetscFunctionBegin;
4198   /* currently sctx is memory bleed */
4199   ierr = PetscMalloc(sizeof(TSMatlabContext),&sctx);CHKERRQ(ierr);
4200   ierr = PetscStrallocpy(func,&sctx->funcname);CHKERRQ(ierr);
4201   /*
4202      This should work, but it doesn't
4203   sctx->ctx = ctx;
4204   mexMakeArrayPersistent(sctx->ctx);
4205   */
4206   sctx->ctx = mxDuplicateArray(ctx);
4207   ierr = TSMonitorSet(ts,TSMonitor_Matlab,sctx,PETSC_NULL);CHKERRQ(ierr);
4208   PetscFunctionReturn(0);
4209 }
4210 #endif
4211 
4212 
4213 
4214 #undef __FUNCT__
4215 #define __FUNCT__ "TSMonitorLGSolution"
4216 /*@C
4217    TSMonitorLGSolution - Monitors progress of the TS solvers by plotting each component of the solution vector
4218        in a time based line graph
4219 
4220    Collective on TS
4221 
4222    Input Parameters:
4223 +  ts - the TS context
4224 .  step - current time-step
4225 .  ptime - current time
4226 -  lg - a line graph object
4227 
4228    Level: intermediate
4229 
4230     Notes: each process in a parallel run displays its component solutions in a separate window
4231 
4232 .keywords: TS,  vector, monitor, view
4233 
4234 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView()
4235 @*/
4236 PetscErrorCode  TSMonitorLGSolution(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
4237 {
4238   PetscErrorCode    ierr;
4239   TSMonitorLGCtx    ctx = (TSMonitorLGCtx)dummy;
4240   const PetscScalar *yy;
4241   PetscInt          dim;
4242 
4243   PetscFunctionBegin;
4244   if (!step) {
4245     PetscDrawAxis  axis;
4246     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4247     ierr = PetscDrawAxisSetLabels(axis,"Solution as function of time","Time","Solution");CHKERRQ(ierr);
4248     ierr = VecGetLocalSize(u,&dim);CHKERRQ(ierr);
4249     ierr = PetscDrawLGSetDimension(ctx->lg,dim);CHKERRQ(ierr);
4250     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4251   }
4252   ierr = VecGetArrayRead(u,&yy);CHKERRQ(ierr);
4253 #if defined(PETSC_USE_COMPLEX)
4254   {
4255     PetscReal *yreal;
4256     PetscInt i,n;
4257     ierr = VecGetLocalSize(u,&n);CHKERRQ(ierr);
4258     ierr = PetscMalloc(n*sizeof(PetscReal),&yreal);CHKERRQ(ierr);
4259     for (i=0; i<n; i++) yreal[i] = PetscRealPart(yy[i]);
4260     ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yreal);CHKERRQ(ierr);
4261     ierr = PetscFree(yreal);CHKERRQ(ierr);
4262   }
4263 #else
4264   ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yy);CHKERRQ(ierr);
4265 #endif
4266   ierr = VecRestoreArrayRead(u,&yy);CHKERRQ(ierr);
4267   if (((ctx->howoften > 0) && (!(step % ctx->howoften)) && (step > -1)) || ((ctx->howoften == -1) && (step == -1))){
4268     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4269   }
4270   PetscFunctionReturn(0);
4271 }
4272 
4273 #undef __FUNCT__
4274 #define __FUNCT__ "TSMonitorLGError"
4275 /*@C
4276    TSMonitorLGError - Monitors progress of the TS solvers by plotting each component of the solution vector
4277        in a time based line graph
4278 
4279    Collective on TS
4280 
4281    Input Parameters:
4282 +  ts - the TS context
4283 .  step - current time-step
4284 .  ptime - current time
4285 -  lg - a line graph object
4286 
4287    Level: intermediate
4288 
4289    Notes:
4290    Only for sequential solves.
4291 
4292    The user must provide the solution using TSSetSolutionFunction() to use this monitor.
4293 
4294    Options Database Keys:
4295 .  -ts_monitor_lg_error - create a graphical monitor of error history
4296 
4297 .keywords: TS,  vector, monitor, view
4298 
4299 .seealso: TSMonitorSet(), TSMonitorDefault(), VecView(), TSSetSolutionFunction()
4300 @*/
4301 PetscErrorCode  TSMonitorLGError(TS ts,PetscInt step,PetscReal ptime,Vec u,void *dummy)
4302 {
4303   PetscErrorCode    ierr;
4304   TSMonitorLGCtx    ctx = (TSMonitorLGCtx)dummy;
4305   const PetscScalar *yy;
4306   Vec               y;
4307   PetscInt          dim;
4308 
4309   PetscFunctionBegin;
4310   if (!step) {
4311     PetscDrawAxis  axis;
4312     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4313     ierr = PetscDrawAxisSetLabels(axis,"Error in solution as function of time","Time","Solution");CHKERRQ(ierr);
4314     ierr = VecGetLocalSize(u,&dim);CHKERRQ(ierr);
4315     ierr = PetscDrawLGSetDimension(ctx->lg,dim);CHKERRQ(ierr);
4316     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4317   }
4318   ierr = VecDuplicate(u,&y);CHKERRQ(ierr);
4319   ierr = TSComputeSolutionFunction(ts,ptime,y);CHKERRQ(ierr);
4320   ierr = VecAXPY(y,-1.0,u);CHKERRQ(ierr);
4321   ierr = VecGetArrayRead(y,&yy);CHKERRQ(ierr);
4322 #if defined(PETSC_USE_COMPLEX)
4323   {
4324     PetscReal *yreal;
4325     PetscInt  i,n;
4326     ierr = VecGetLocalSize(y,&n);CHKERRQ(ierr);
4327     ierr = PetscMalloc(n*sizeof(PetscReal),&yreal);CHKERRQ(ierr);
4328     for (i=0; i<n; i++) yreal[i] = PetscRealPart(yy[i]);
4329     ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yreal);CHKERRQ(ierr);
4330     ierr = PetscFree(yreal);CHKERRQ(ierr);
4331   }
4332 #else
4333   ierr = PetscDrawLGAddCommonPoint(ctx->lg,ptime,yy);CHKERRQ(ierr);
4334 #endif
4335   ierr = VecRestoreArrayRead(y,&yy);CHKERRQ(ierr);
4336   ierr = VecDestroy(&y);CHKERRQ(ierr);
4337   if (((ctx->howoften > 0) && (!(step % ctx->howoften)) && (step > -1)) || ((ctx->howoften == -1) && (step == -1))){
4338     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4339   }
4340   PetscFunctionReturn(0);
4341 }
4342 
4343 #undef __FUNCT__
4344 #define __FUNCT__ "TSMonitorLGSNESIterations"
4345 PetscErrorCode TSMonitorLGSNESIterations(TS ts,PetscInt n,PetscReal ptime,Vec v,void *monctx)
4346 {
4347   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
4348   PetscReal      x = ptime,y;
4349   PetscErrorCode ierr;
4350   PetscInt       its;
4351 
4352   PetscFunctionBegin;
4353   if (!n) {
4354     PetscDrawAxis  axis;
4355     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4356     ierr = PetscDrawAxisSetLabels(axis,"Nonlinear iterations as function of time","Time","SNES Iterations");CHKERRQ(ierr);
4357     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4358     ctx->snes_its  = 0;
4359   }
4360   ierr = TSGetSNESIterations(ts,&its);CHKERRQ(ierr);
4361   y    = its - ctx->snes_its;
4362   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
4363   if (((ctx->howoften > 0) && (!(n % ctx->howoften)) && (n > -1)) || ((ctx->howoften == -1) && (n == -1))){
4364     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4365   }
4366   ctx->snes_its = its;
4367   PetscFunctionReturn(0);
4368 }
4369 
4370 #undef __FUNCT__
4371 #define __FUNCT__ "TSMonitorLGKSPIterations"
4372 PetscErrorCode TSMonitorLGKSPIterations(TS ts,PetscInt n,PetscReal ptime,Vec v,void *monctx)
4373 {
4374   TSMonitorLGCtx ctx = (TSMonitorLGCtx) monctx;
4375   PetscReal      x = ptime,y;
4376   PetscErrorCode ierr;
4377   PetscInt       its;
4378 
4379   PetscFunctionBegin;
4380   if (!n) {
4381     PetscDrawAxis  axis;
4382     ierr = PetscDrawLGGetAxis(ctx->lg,&axis);CHKERRQ(ierr);
4383     ierr = PetscDrawAxisSetLabels(axis,"Linear iterations as function of time","Time","KSP Iterations");CHKERRQ(ierr);
4384     ierr = PetscDrawLGReset(ctx->lg);CHKERRQ(ierr);
4385     ctx->ksp_its = 0;
4386   }
4387   ierr = TSGetKSPIterations(ts,&its);CHKERRQ(ierr);
4388   y    = its - ctx->ksp_its;
4389   ierr = PetscDrawLGAddPoint(ctx->lg,&x,&y);CHKERRQ(ierr);
4390   if (((ctx->howoften > 0) && (!(n % ctx->howoften)) && (n > -1)) || ((ctx->howoften == -1) && (n == -1))){
4391     ierr = PetscDrawLGDraw(ctx->lg);CHKERRQ(ierr);
4392   }
4393   ctx->ksp_its = its;
4394   PetscFunctionReturn(0);
4395 }
4396 
4397 #undef __FUNCT__
4398 #define __FUNCT__ "TSComputeLinearStability"
4399 /*@
4400    TSComputeLinearStability - computes the linear stability function at a point
4401 
4402    Collective on TS and Vec
4403 
4404    Input Parameters:
4405 +  ts - the TS context
4406 -  xr,xi - real and imaginary part of input arguments
4407 
4408    Output Parameters:
4409 .  yr,yi - real and imaginary part of function value
4410 
4411    Level: developer
4412 
4413 .keywords: TS, compute
4414 
4415 .seealso: TSSetRHSFunction(), TSComputeIFunction()
4416 @*/
4417 PetscErrorCode TSComputeLinearStability(TS ts,PetscReal xr,PetscReal xi,PetscReal *yr,PetscReal *yi)
4418 {
4419   PetscErrorCode ierr;
4420 
4421   PetscFunctionBegin;
4422   PetscValidHeaderSpecific(ts,TS_CLASSID,1);
4423   if (!ts->ops->linearstability) SETERRQ(((PetscObject)ts)->comm,PETSC_ERR_SUP,"Linearized stability function not provided for this method");
4424   ierr = (*ts->ops->linearstability)(ts,xr,xi,yr,yi);CHKERRQ(ierr);
4425   PetscFunctionReturn(0);
4426 }
4427