Actual source code: snesut.c

  1: #define PETSCSNES_DLL

 3:  #include include/private/snesimpl.h

  7: /*@C
  8:    SNESMonitorSolution - Monitors progress of the SNES solvers by calling 
  9:    VecView() for the approximate solution at each iteration.

 11:    Collective on SNES

 13:    Input Parameters:
 14: +  snes - the SNES context
 15: .  its - iteration number
 16: .  fgnorm - 2-norm of residual
 17: -  dummy - either a viewer or PETSC_NULL

 19:    Level: intermediate

 21: .keywords: SNES, nonlinear, vector, monitor, view

 23: .seealso: SNESMonitorSet(), SNESMonitorDefault(), VecView()
 24: @*/
 25: PetscErrorCode  SNESMonitorSolution(SNES snes,PetscInt its,PetscReal fgnorm,void *dummy)
 26: {
 28:   Vec            x;
 29:   PetscViewer    viewer = (PetscViewer) dummy;

 32:   SNESGetSolution(snes,&x);
 33:   if (!viewer) {
 34:     MPI_Comm comm;
 35:     PetscObjectGetComm((PetscObject)snes,&comm);
 36:     viewer = PETSC_VIEWER_DRAW_(comm);
 37:   }
 38:   VecView(x,viewer);

 40:   return(0);
 41: }

 45: /*@C
 46:    SNESMonitorResidual - Monitors progress of the SNES solvers by calling 
 47:    VecView() for the residual at each iteration.

 49:    Collective on SNES

 51:    Input Parameters:
 52: +  snes - the SNES context
 53: .  its - iteration number
 54: .  fgnorm - 2-norm of residual
 55: -  dummy - either a viewer or PETSC_NULL

 57:    Level: intermediate

 59: .keywords: SNES, nonlinear, vector, monitor, view

 61: .seealso: SNESMonitorSet(), SNESMonitorDefault(), VecView()
 62: @*/
 63: PetscErrorCode  SNESMonitorResidual(SNES snes,PetscInt its,PetscReal fgnorm,void *dummy)
 64: {
 66:   Vec            x;
 67:   PetscViewer    viewer = (PetscViewer) dummy;

 70:   SNESGetFunction(snes,&x,0,0);
 71:   if (!viewer) {
 72:     MPI_Comm comm;
 73:     PetscObjectGetComm((PetscObject)snes,&comm);
 74:     viewer = PETSC_VIEWER_DRAW_(comm);
 75:   }
 76:   VecView(x,viewer);

 78:   return(0);
 79: }

 83: /*@C
 84:    SNESMonitorSolutionUpdate - Monitors progress of the SNES solvers by calling 
 85:    VecView() for the UPDATE to the solution at each iteration.

 87:    Collective on SNES

 89:    Input Parameters:
 90: +  snes - the SNES context
 91: .  its - iteration number
 92: .  fgnorm - 2-norm of residual
 93: -  dummy - either a viewer or PETSC_NULL

 95:    Level: intermediate

 97: .keywords: SNES, nonlinear, vector, monitor, view

 99: .seealso: SNESMonitorSet(), SNESMonitorDefault(), VecView()
100: @*/
101: PetscErrorCode  SNESMonitorSolutionUpdate(SNES snes,PetscInt its,PetscReal fgnorm,void *dummy)
102: {
104:   Vec            x;
105:   PetscViewer    viewer = (PetscViewer) dummy;

108:   SNESGetSolutionUpdate(snes,&x);
109:   if (!viewer) {
110:     MPI_Comm comm;
111:     PetscObjectGetComm((PetscObject)snes,&comm);
112:     viewer = PETSC_VIEWER_DRAW_(comm);
113:   }
114:   VecView(x,viewer);

116:   return(0);
117: }

121: /*@C
122:    SNESMonitorDefault - Monitors progress of the SNES solvers (default).

124:    Collective on SNES

126:    Input Parameters:
127: +  snes - the SNES context
128: .  its - iteration number
129: .  fgnorm - 2-norm of residual
130: -  dummy - unused context

132:    Notes:
133:    This routine prints the residual norm at each iteration.

135:    Level: intermediate

137: .keywords: SNES, nonlinear, default, monitor, norm

139: .seealso: SNESMonitorSet(), SNESMonitorSolution()
140: @*/
141: PetscErrorCode  SNESMonitorDefault(SNES snes,PetscInt its,PetscReal fgnorm,void *dummy)
142: {
143:   PetscErrorCode          ierr;
144:   PetscViewerASCIIMonitor viewer = (PetscViewerASCIIMonitor) dummy;

147:   if (!dummy) {
148:     PetscViewerASCIIMonitorCreate(snes->comm,"stdout",0,&viewer);
149:   }
150:   PetscViewerASCIIMonitorPrintf(viewer,"%3D SNES Function norm %14.12e \n",its,fgnorm);
151:   if (!dummy) {
152:     PetscViewerASCIIMonitorDestroy(viewer);
153:   }
154:   return(0);
155: }

157: typedef struct {
158:   PetscViewerASCIIMonitor viewer;
159:   PetscReal               *history;
160: } SNESMonitorRatioContext;

164: /*@C
165:    SNESMonitorRatio - Monitors progress of the SNES solvers by printing the ratio
166:    of residual norm at each iteration to the previous.

168:    Collective on SNES

170:    Input Parameters:
171: +  snes - the SNES context
172: .  its - iteration number
173: .  fgnorm - 2-norm of residual (or gradient)
174: -  dummy -  context of monitor

176:    Level: intermediate

178: .keywords: SNES, nonlinear, monitor, norm

180: .seealso: SNESMonitorSet(), SNESMonitorSolution()
181: @*/
182: PetscErrorCode  SNESMonitorRatio(SNES snes,PetscInt its,PetscReal fgnorm,void *dummy)
183: {
184:   PetscErrorCode          ierr;
185:   PetscInt                len;
186:   PetscReal               *history;
187:   SNESMonitorRatioContext *ctx = (SNESMonitorRatioContext*)dummy;

190:   SNESGetConvergenceHistory(snes,&history,PETSC_NULL,&len);
191:   if (!its || !history || its > len) {
192:     PetscViewerASCIIMonitorPrintf(ctx->viewer,"%3D SNES Function norm %14.12e \n",its,fgnorm);
193:   } else {
194:     PetscReal ratio = fgnorm/history[its-1];
195:     PetscViewerASCIIMonitorPrintf(ctx->viewer,"%3D SNES Function norm %14.12e %G \n",its,fgnorm,ratio);
196:   }
197:   return(0);
198: }

200: /*
201:    If the we set the history monitor space then we must destroy it
202: */
205: PetscErrorCode SNESMonitorRatioDestroy(void *ct)
206: {
207:   PetscErrorCode          ierr;
208:   SNESMonitorRatioContext *ctx = (SNESMonitorRatioContext*)ct;

211:   PetscFree(ctx->history);
212:   PetscViewerASCIIMonitorDestroy(ctx->viewer);
213:   PetscFree(ctx);
214:   return(0);
215: }

219: /*@C
220:    SNESMonitorSetRatio - Sets SNES to use a monitor that prints the 
221:    ratio of the function norm at each iteration.

223:    Collective on SNES

225:    Input Parameters:
226: +   snes - the SNES context
227: -   viewer - ASCII viewer to print output

229:    Level: intermediate

231: .keywords: SNES, nonlinear, monitor, norm

233: .seealso: SNESMonitorSet(), SNESMonitorSolution(), SNESMonitorDefault()
234: @*/
235: PetscErrorCode  SNESMonitorSetRatio(SNES snes,PetscViewerASCIIMonitor viewer)
236: {
237:   PetscErrorCode          ierr;
238:   SNESMonitorRatioContext *ctx;
239:   PetscReal               *history;

242:   if (!viewer) {
243:     PetscViewerASCIIMonitorCreate(snes->comm,"stdout",0,&viewer);
244:     PetscObjectReference((PetscObject)viewer);
245:   }
246:   PetscNew(SNESMonitorRatioContext,&ctx);
247:   SNESGetConvergenceHistory(snes,&history,PETSC_NULL,PETSC_NULL);
248:   if (!history) {
249:     PetscMalloc(100*sizeof(PetscReal),&ctx->history);
250:     SNESSetConvergenceHistory(snes,ctx->history,0,100,PETSC_TRUE);
251:   }
252:   ctx->viewer = viewer;
253:   SNESMonitorSet(snes,SNESMonitorRatio,ctx,SNESMonitorRatioDestroy);
254:   return(0);
255: }

257: /* ---------------------------------------------------------------- */
260: /*
261:      Default (short) SNES Monitor, same as SNESMonitorDefault() except
262:   it prints fewer digits of the residual as the residual gets smaller.
263:   This is because the later digits are meaningless and are often 
264:   different on different machines; by using this routine different 
265:   machines will usually generate the same output.
266: */
267: PetscErrorCode  SNESMonitorDefaultShort(SNES snes,PetscInt its,PetscReal fgnorm,void *dummy)
268: {
269:   PetscErrorCode          ierr;
270:   PetscViewerASCIIMonitor viewer = (PetscViewerASCIIMonitor) dummy;

273:   if (!dummy) {
274:     PetscViewerASCIIMonitorCreate(snes->comm,"stdout",0,&viewer);
275:   }
276:   if (fgnorm > 1.e-9) {
277:     PetscViewerASCIIMonitorPrintf(viewer,"%3D SNES Function norm %G \n",its,fgnorm);
278:   } else if (fgnorm > 1.e-11){
279:     PetscViewerASCIIMonitorPrintf(viewer,"%3D SNES Function norm %5.3e \n",its,fgnorm);
280:   } else {
281:     PetscViewerASCIIMonitorPrintf(viewer,"%3D SNES Function norm < 1.e-11\n",its);
282:   }
283:   if (!dummy) {
284:     PetscViewerASCIIMonitorDestroy(viewer);
285:   }
286:   return(0);
287: }
288: /* ---------------------------------------------------------------- */
291: /*@C 
292:    SNESDefaultConverged - Convergence test of the solvers for
293:    systems of nonlinear equations (default).

295:    Collective on SNES

297:    Input Parameters:
298: +  snes - the SNES context
299: .  it - the iteration (0 indicates before any Newton steps)
300: .  xnorm - 2-norm of current iterate
301: .  pnorm - 2-norm of current step 
302: .  fnorm - 2-norm of function at current iterate
303: -  dummy - unused context

305:    Output Parameter:
306: .   reason  - one of
307: $  SNES_CONVERGED_FNORM_ABS       - (fnorm < abstol),
308: $  SNES_CONVERGED_PNORM_RELATIVE  - (pnorm < xtol*xnorm),
309: $  SNES_CONVERGED_FNORM_RELATIVE  - (fnorm < rtol*fnorm0),
310: $  SNES_DIVERGED_FUNCTION_COUNT   - (nfct > maxf),
311: $  SNES_DIVERGED_FNORM_NAN        - (fnorm == NaN),
312: $  SNES_CONVERGED_ITERATING       - (otherwise),

314:    where
315: +    maxf - maximum number of function evaluations,
316:             set with SNESSetTolerances()
317: .    nfct - number of function evaluations,
318: .    abstol - absolute function norm tolerance,
319:             set with SNESSetTolerances()
320: -    rtol - relative function norm tolerance, set with SNESSetTolerances()

322:    Level: intermediate

324: .keywords: SNES, nonlinear, default, converged, convergence

326: .seealso: SNESSetConvergenceTest()
327: @*/
328: PetscErrorCode  SNESDefaultConverged(SNES snes,PetscInt it,PetscReal xnorm,PetscReal pnorm,PetscReal fnorm,SNESConvergedReason *reason,void *dummy)
329: {

335: 
336:   *reason = SNES_CONVERGED_ITERATING;

338:   if (!it) {
339:     /* set parameter for default relative tolerance convergence test */
340:     snes->ttol = fnorm*snes->rtol;
341:   }
342:   if (fnorm != fnorm) {
343:     PetscInfo(snes,"Failed to converged, function norm is NaN\n");
344:     *reason = SNES_DIVERGED_FNORM_NAN;
345:   } else if (fnorm < snes->abstol) {
346:     PetscInfo2(snes,"Converged due to function norm %G < %G\n",fnorm,snes->abstol);
347:     *reason = SNES_CONVERGED_FNORM_ABS;
348:   } else if (snes->nfuncs >= snes->max_funcs) {
349:     PetscInfo2(snes,"Exceeded maximum number of function evaluations: %D > %D\n",snes->nfuncs,snes->max_funcs);
350:     *reason = SNES_DIVERGED_FUNCTION_COUNT;
351:   }

353:   if (it && !*reason) {
354:     if (fnorm <= snes->ttol) {
355:       PetscInfo2(snes,"Converged due to function norm %G < %G (relative tolerance)\n",fnorm,snes->ttol);
356:       *reason = SNES_CONVERGED_FNORM_RELATIVE;
357:     } else if (pnorm < snes->xtol*xnorm) {
358:       PetscInfo3(snes,"Converged due to small update length: %G < %G * %G\n",pnorm,snes->xtol,xnorm);
359:       *reason = SNES_CONVERGED_PNORM_RELATIVE;
360:     }
361:   }
362:   return(0);
363: }

367: /*@C 
368:    SNESSkipConverged - Convergence test for SNES that NEVER returns as
369:    converged, UNLESS the maximum number of iteration have been reached.

371:    Collective on SNES

373:    Input Parameters:
374: +  snes - the SNES context
375: .  it - the iteration (0 indicates before any Newton steps)
376: .  xnorm - 2-norm of current iterate
377: .  pnorm - 2-norm of current step 
378: .  fnorm - 2-norm of function at current iterate
379: -  dummy - unused context

381:    Output Parameter:
382: .   reason  - SNES_CONVERGED_ITERATING or SNES_DIVERGED_FNORM_NAN

384:    Notes:
385:    Convergence is then declared after a fixed number of iterations have been used.
386:                     
387:    Level: advanced

389: .keywords: SNES, nonlinear, skip, converged, convergence

391: .seealso: SNESSetConvergenceTest()
392: @*/
393: PetscErrorCode  SNESSkipConverged(SNES snes,PetscInt it,PetscReal xnorm,PetscReal pnorm,PetscReal fnorm,SNESConvergedReason *reason,void *dummy)
394: {


401:   *reason = SNES_CONVERGED_ITERATING;

403:   if (fnorm != fnorm) {
404:     PetscInfo(snes,"Failed to converged, function norm is NaN\n");
405:     *reason = SNES_DIVERGED_FNORM_NAN;
406:   } else if(it == snes->max_its) {
407:     *reason = SNES_CONVERGED_ITS;
408:   }
409:   return(0);
410: }