Actual source code: viewreg.c

petsc-master 2017-11-22
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  2:  #include <petsc/private/viewerimpl.h>
  3:  #include <petsc/private/hash.h>
  4: #if defined(PETSC_HAVE_SAWS)
  5:  #include <petscviewersaws.h>
  6: #endif

  8: PetscFunctionList PetscViewerList = 0;


 11: PetscOptionsHelpPrinted PetscOptionsHelpPrintedSingleton = NULL;
 12: KHASH_SET_INIT_STR(HTPrinted)
 13: struct  _n_PetscOptionsHelpPrinted{
 14:   khash_t(HTPrinted) *printed;
 15:   PetscSegBuffer     strings;
 16: };

 18: PetscErrorCode PetscOptionsHelpPrintedDestroy(PetscOptionsHelpPrinted *hp)
 19: {

 23:   if (!*hp) return(0);
 24:   kh_destroy(HTPrinted,(*hp)->printed);
 25:   PetscSegBufferDestroy(&(*hp)->strings);
 26:   PetscFree(*hp);
 27:   return(0);
 28: }

 30: /*@C
 31:       PetscOptionsHelpPrintedCreate - Creates an object used to manage tracking which help messages have
 32:          been printed so they will not be printed again.

 34:      Not collective

 36:     Level: developer

 38: .seealso: PetscOptionsHelpPrintedCheck(), PetscOptionsHelpPrintChecked()
 39: @*/
 40: PetscErrorCode PetscOptionsHelpPrintedCreate(PetscOptionsHelpPrinted *hp)
 41: {
 42:   PetscErrorCode             ierr;

 45:   PetscNew(hp);
 46:   (*hp)->printed = kh_init(HTPrinted);
 47:   PetscSegBufferCreate(sizeof(char),10000,&(*hp)->strings);
 48:   return(0);
 49: }

 51: /*@C
 52:       PetscOptionsHelpPrintedCheck - Checks if a particular pre, name pair has previous been entered (meaning the help message was printed)

 54:      Not collective

 56:     Input Parameters:
 57: +     hp - the object used to manage tracking what help messages have been printed
 58: .     pre - the prefix part of the string, many be NULL
 59: -     name - the string to look for (cannot be NULL)

 61:     Output Parameter:
 62: .     found - PETSC_TRUE if the string was already set

 64:     Level: intermediate


 67: .seealso: PetscOptionsHelpPrintedCreate()
 68: @*/
 69: PetscErrorCode PetscOptionsHelpPrintedCheck(PetscOptionsHelpPrinted hp,const char *pre,const char* name,PetscBool *found)
 70: {
 71:   size_t          l1,l2;
 72: #if !defined(PETSC_HAVE_THREADSAFETY)
 73:   char            *both;
 74:   khint_t         newitem;
 75: #endif
 76:   PetscErrorCode  ierr;

 79:   PetscStrlen(pre,&l1);
 80:   PetscStrlen(name,&l2);
 81:   if (l1+l2 == 0) {
 82:     *found = PETSC_FALSE;
 83:     return(0);
 84:   }
 85: #if !defined(PETSC_HAVE_THREADSAFETY)
 86:   PetscSegBufferGet(hp->strings,l1+l2+1,&both);
 87:   PetscStrcpy(both,pre);
 88:   PetscStrcat(both,name);
 89:   kh_put(HTPrinted,hp->printed,both,&newitem);
 90:   if (!newitem) {
 91:     PetscSegBufferUnuse(hp->strings,l1+l2+1);
 92:   }
 93:   *found = newitem ? PETSC_FALSE : PETSC_TRUE;
 94: #else
 95:   *found = PETSC_FALSE;
 96: #endif
 97:   return(0);
 98: }

100: static PetscBool noviewer = PETSC_FALSE;
101: static PetscBool noviewers[PETSCVIEWERGETVIEWEROFFPUSHESMAX];
102: static PetscInt  inoviewers = 0;

104: /*@
105:   PetscOptionsPushGetViewerOff - control whether PetscOptionsGetViewer returns a viewer.

107:   Logically Collective

109:   Input Parameter:
110: . flg - PETSC_TRUE to turn off viewer creation, PETSC_FALSE to turn it on.

112:   Level: developer

114:   Notes: Calling XXXViewFromOptions in an inner loop can be very expensive.  This can appear, for example, when using
115:    many small subsolves.  Call this function to control viewer creation in PetscOptionsGetViewer, thus removing the expensive XXXViewFromOptions calls.

117: .seealso: PetscOptionsGetViewer(), PetscOptionsPopGetViewerOff()
118: @*/
119: PetscErrorCode  PetscOptionsPushGetViewerOff(PetscBool flg)
120: {
122:   if (inoviewers > PETSCVIEWERGETVIEWEROFFPUSHESMAX - 1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many PetscOptionsPushGetViewerOff(), perhaps you forgot PetscOptionsPopGetViewerOff()?");

124:   noviewers[inoviewers++] = noviewer;
125:   noviewer = flg;
126:   return(0);
127: }

129: /*@
130:   PetscOptionsPopGetViewerOff - reset whether PetscOptionsGetViewer returns a viewer.

132:   Logically Collective

134:   Level: developer

136:   Notes: Calling XXXViewFromOptions in an inner loop can be very expensive.  This can appear, for example, when using
137:    many small subsolves.  Call this function to control viewer creation in PetscOptionsGetViewer, thus removing the expensive XXXViewFromOptions calls.

139: .seealso: PetscOptionsGetViewer(), PetscOptionsPushGetViewerOff()
140: @*/
141: PetscErrorCode  PetscOptionsPopGetViewerOff(void)
142: {
144:   if (!inoviewers) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many PetscOptionsPopGetViewerOff(), perhaps you forgot PetscOptionsPushGetViewerOff()?");
145:   noviewer = noviewers[--inoviewers];
146:   return(0);
147: }

149: /*@
150:   PetscOptionsGetViewerOff - does PetscOptionsGetViewer return a viewer?

152:   Logically Collective

154:   Output Parameter:
155: . flg - whether viewers are returned.

157:   Level: developer

159:   Notes: Calling XXXViewFromOptions in an inner loop can be very expensive.  This can appear, for example, when using
160:    many small subsolves.

162: .seealso: PetscOptionsGetViewer(), PetscOptionsPushGetViewerOff(), PetscOptionsPopGetViewerOff()
163: @*/
164: PetscErrorCode  PetscOptionsGetViewerOff(PetscBool *flg)
165: {
168:   *flg = noviewer;
169:   return(0);
170: }

172: /*@C
173:    PetscOptionsGetViewer - Gets a viewer appropriate for the type indicated by the user

175:    Collective on MPI_Comm

177:    Input Parameters:
178: +  comm - the communicator to own the viewer
179: .  pre - the string to prepend to the name or NULL
180: -  name - the option one is seeking

182:    Output Parameter:
183: +  viewer - the viewer, pass NULL if not needed
184: .  format - the PetscViewerFormat requested by the user, pass NULL if not needed
185: -  set - PETSC_TRUE if found, else PETSC_FALSE

187:    Level: intermediate

189:    Notes: If no value is provided ascii:stdout is used
190: $       ascii[:[filename][:[format][:append]]]    defaults to stdout - format can be one of ascii_info, ascii_info_detail, or ascii_matlab, 
191:                                                   for example ascii::ascii_info prints just the information about the object not all details
192:                                                   unless :append is given filename opens in write mode, overwriting what was already there
193: $       binary[:[filename][:[format][:append]]]   defaults to the file binaryoutput
194: $       draw[:drawtype[:filename]]                for example, draw:tikz, draw:tikz:figure.tex  or draw:x 
195: $       socket[:port]                             defaults to the standard output port
196: $       saws[:communicatorname]                    publishes object to the Scientific Application Webserver (SAWs)

198:    Use PetscViewerDestroy() after using the viewer, otherwise a memory leak will occur

200:    You can control whether calls to this function create a viewer (or return early with *set of PETSC_FALSE) with
201:    PetscOptionsPushGetViewerOff.  This is useful if calling many small subsolves, in which case XXXViewFromOptions can take
202:    an appreciable fraction of the runtime.

204:    If PETSc is configured with --with-viewfromoptions=0 this function always returns with *set of PETSC_FALSE

206: .seealso: PetscOptionsGetReal(), PetscOptionsHasName(), PetscOptionsGetString(),
207:           PetscOptionsGetIntArray(), PetscOptionsGetRealArray(), PetscOptionsBool()
208:           PetscOptionsInt(), PetscOptionsString(), PetscOptionsReal(), PetscOptionsBool(),
209:           PetscOptionsName(), PetscOptionsBegin(), PetscOptionsEnd(), PetscOptionsHead(),
210:           PetscOptionsStringArray(),PetscOptionsRealArray(), PetscOptionsScalar(),
211:           PetscOptionsBoolGroupBegin(), PetscOptionsBoolGroup(), PetscOptionsBoolGroupEnd(),
212:           PetscOptionsFList(), PetscOptionsEList(), PetscOptionsPushGetViewerOff(), PetscOptionsPopGetViewerOff(),
213:           PetscOptionsGetViewerOff()
214: @*/
215: PetscErrorCode  PetscOptionsGetViewer(MPI_Comm comm,const char pre[],const char name[],PetscViewer *viewer,PetscViewerFormat *format,PetscBool  *set)
216: {
217:   char                           *value;
218:   PetscErrorCode                 ierr;
219:   PetscBool                      flag,hashelp;


224:   if (set) *set = PETSC_FALSE;
225: #if defined(PETSC_SKIP_VIEWFROMOPTIONS)
226:   return(0);
227: #endif
228:   PetscOptionsGetViewerOff(&flag);
229:   if (flag) return(0);

231:   PetscOptionsHasName(NULL,NULL,"-help",&hashelp);
232:   if (hashelp) {
233:     PetscBool found;

235:     if (!PetscOptionsHelpPrintedSingleton) {
236:       PetscOptionsHelpPrintedCreate(&PetscOptionsHelpPrintedSingleton);
237:     }
238:     PetscOptionsHelpPrintedCheck(PetscOptionsHelpPrintedSingleton,pre,name,&found);
239:     if (!found) {
240:       if (viewer) {
241:         (*PetscHelpPrintf)(comm,"\n  -%s%s ascii[:[filename][:[format][:append]]]: %s (%s)\n",pre ? pre : "",name+1,"Prints object to stdout or ASCII file","PetscOptionsGetViewer");
242:         (*PetscHelpPrintf)(comm,"    -%s%s binary[:[filename][:[format][:append]]]: %s (%s)\n",pre ? pre : "",name+1,"Saves object to a binary file","PetscOptionsGetViewer");
243:         (*PetscHelpPrintf)(comm,"    -%s%s draw[:[drawtype][:filename|format]] %s (%s)\n",pre ? pre : "",name+1,"Draws object","PetscOptionsGetViewer");
244:         (*PetscHelpPrintf)(comm,"    -%s%s socket[:port]: %s (%s)\n",pre ? pre : "",name+1,"Pushes object to a Unix socket","PetscOptionsGetViewer");
245:         (*PetscHelpPrintf)(comm,"    -%s%s saws[:communicatorname]: %s (%s)\n\n",pre ? pre : "",name+1,"Publishes object to SAWs","PetscOptionsGetViewer");
246:       } else {
247:         (*PetscHelpPrintf)(comm,"    -%s%s\n",pre ? pre : "",name+1);
248:       }
249:     }
250:   }

252:   if (format) *format = PETSC_VIEWER_DEFAULT;
253:   PetscOptionsFindPair_Private(NULL,pre,name,&value,&flag);
254:   if (flag) {
255:     if (set) *set = PETSC_TRUE;
256:     if (!value) {
257:       if (viewer) {
258:         PetscViewerASCIIGetStdout(comm,viewer);
259:         PetscObjectReference((PetscObject)*viewer);
260:       }
261:     } else {
262:       char       *loc0_vtype,*loc1_fname,*loc2_fmt = NULL,*loc3_fmode = NULL;
263:       PetscInt   cnt;
264:       const char *viewers[] = {PETSCVIEWERASCII,PETSCVIEWERBINARY,PETSCVIEWERDRAW,PETSCVIEWERSOCKET,PETSCVIEWERMATLAB,PETSCVIEWERSAWS,PETSCVIEWERVTK,PETSCVIEWERHDF5,PETSCVIEWERGLVIS,0};

266:       PetscStrallocpy(value,&loc0_vtype);
267:       PetscStrchr(loc0_vtype,':',&loc1_fname);
268:       if (loc1_fname) {
269:         *loc1_fname++ = 0;
270:         PetscStrchr(loc1_fname,':',&loc2_fmt);
271:       }
272:       if (loc2_fmt) {
273:         *loc2_fmt++ = 0;
274:         PetscStrchr(loc2_fmt,':',&loc3_fmode);
275:       }
276:       if (loc3_fmode) *loc3_fmode++ = 0;
277:       PetscStrendswithwhich(*loc0_vtype ? loc0_vtype : "ascii",viewers,&cnt);
278:       if (cnt > (PetscInt) sizeof(viewers)-1) SETERRQ1(comm,PETSC_ERR_ARG_OUTOFRANGE,"Unknown viewer type: %s",loc0_vtype);
279:       if (viewer) {
280:         if (!loc1_fname) {
281:           switch (cnt) {
282:           case 0:
283:             PetscViewerASCIIGetStdout(comm,viewer);
284:             break;
285:           case 1:
286:             if (!(*viewer = PETSC_VIEWER_BINARY_(comm))) CHKERRQ(PETSC_ERR_PLIB);
287:             break;
288:           case 2:
289:             if (!(*viewer = PETSC_VIEWER_DRAW_(comm))) CHKERRQ(PETSC_ERR_PLIB);
290:             break;
291: #if defined(PETSC_USE_SOCKET_VIEWER)
292:           case 3:
293:             if (!(*viewer = PETSC_VIEWER_SOCKET_(comm))) CHKERRQ(PETSC_ERR_PLIB);
294:             break;
295: #endif
296: #if defined(PETSC_HAVE_MATLAB_ENGINE)
297:           case 4:
298:             if (!(*viewer = PETSC_VIEWER_MATLAB_(comm))) CHKERRQ(PETSC_ERR_PLIB);
299:             break;
300: #endif
301: #if defined(PETSC_HAVE_SAWS)
302:           case 5:
303:             if (!(*viewer = PETSC_VIEWER_SAWS_(comm))) CHKERRQ(PETSC_ERR_PLIB);
304:             break;
305: #endif
306: #if defined(PETSC_HAVE_HDF5)
307:           case 7:
308:             if (!(*viewer = PETSC_VIEWER_HDF5_(comm))) CHKERRQ(PETSC_ERR_PLIB);
309:             break;
310: #endif
311:           case 8:
312:             if (!(*viewer = PETSC_VIEWER_GLVIS_(comm))) CHKERRQ(PETSC_ERR_PLIB);
313:             break;
314:           default: SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Unsupported viewer %s",loc0_vtype);
315:           }
316:           PetscObjectReference((PetscObject)*viewer);
317:         } else {
318:           if (loc2_fmt && !*loc1_fname && (cnt == 0)) { /* ASCII format without file name */
319:             PetscViewerASCIIGetStdout(comm,viewer);
320:             PetscObjectReference((PetscObject)*viewer);
321:           } else {
322:             PetscFileMode fmode;
323:             PetscViewerCreate(comm,viewer);
324:             PetscViewerSetType(*viewer,*loc0_vtype ? loc0_vtype : "ascii");
325:             fmode = FILE_MODE_WRITE;
326:             if (loc3_fmode && *loc3_fmode) { /* Has non-empty file mode ("write" or "append") */
327:               PetscEnumFind(PetscFileModes,loc3_fmode,(PetscEnum*)&fmode,&flag);
328:               if (!flag) SETERRQ1(comm,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unknown file mode: %s",loc3_fmode);
329:             }
330:             if (loc2_fmt) {
331:               PetscBool tk,im;
332:               PetscStrcmp(loc1_fname,"tikz",&tk);
333:               PetscStrcmp(loc1_fname,"image",&im);
334:               if (tk || im) {
335:                 PetscViewerDrawSetInfo(*viewer,NULL,loc2_fmt,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE);
336:                 *loc2_fmt = 0;
337:               }
338:             }
339:             PetscViewerFileSetMode(*viewer,flag?fmode:FILE_MODE_WRITE);
340:             PetscViewerFileSetName(*viewer,loc1_fname);
341:             if (*loc1_fname) {
342:               PetscViewerDrawSetDrawType(*viewer,loc1_fname);
343:             }
344:           }
345:         }
346:       }
347:       if (viewer) {
348:         PetscViewerSetUp(*viewer);
349:       }
350:       if (loc2_fmt && *loc2_fmt) {
351:         PetscEnumFind(PetscViewerFormats,loc2_fmt,(PetscEnum*)format,&flag);
352:         if (!flag) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Unknown viewer format %s",loc2_fmt);
353:       }
354:       PetscFree(loc0_vtype);
355:     }
356:   }
357:   return(0);
358: }

360: /*@
361:    PetscViewerCreate - Creates a viewing context

363:    Collective on MPI_Comm

365:    Input Parameter:
366: .  comm - MPI communicator

368:    Output Parameter:
369: .  inviewer - location to put the PetscViewer context

371:    Level: advanced

373:    Concepts: graphics^creating PetscViewer
374:    Concepts: file input/output^creating PetscViewer
375:    Concepts: sockets^creating PetscViewer

377: .seealso: PetscViewerDestroy(), PetscViewerSetType(), PetscViewerType

379: @*/
380: PetscErrorCode  PetscViewerCreate(MPI_Comm comm,PetscViewer *inviewer)
381: {
382:   PetscViewer    viewer;

386:   *inviewer = 0;
387:   PetscViewerInitializePackage();
388:   PetscHeaderCreate(viewer,PETSC_VIEWER_CLASSID,"PetscViewer","PetscViewer","Viewer",comm,PetscViewerDestroy,NULL);
389:   *inviewer    = viewer;
390:   viewer->data = 0;
391:   return(0);
392: }

394: /*@C
395:    PetscViewerSetType - Builds PetscViewer for a particular implementation.

397:    Collective on PetscViewer

399:    Input Parameter:
400: +  viewer      - the PetscViewer context
401: -  type        - for example, PETSCVIEWERASCII

403:    Options Database Command:
404: .  -draw_type  <type> - Sets the type; use -help for a list
405:     of available methods (for instance, ascii)

407:    Level: advanced

409:    Notes:
410:    See "include/petscviewer.h" for available methods (for instance,
411:    PETSCVIEWERSOCKET)

413: .seealso: PetscViewerCreate(), PetscViewerGetType(), PetscViewerType, PetscViewerPushFormat()
414: @*/
415: PetscErrorCode  PetscViewerSetType(PetscViewer viewer,PetscViewerType type)
416: {
417:   PetscErrorCode ierr,(*r)(PetscViewer);
418:   PetscBool      match;

423:   PetscObjectTypeCompare((PetscObject)viewer,type,&match);
424:   if (match) return(0);

426:   /* cleanup any old type that may be there */
427:   if (viewer->data) {
428:     (*viewer->ops->destroy)(viewer);

430:     viewer->ops->destroy = NULL;
431:     viewer->data         = 0;
432:   }
433:   PetscMemzero(viewer->ops,sizeof(struct _PetscViewerOps));

435:    PetscFunctionListFind(PetscViewerList,type,&r);
436:   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unknown PetscViewer type given: %s",type);

438:   PetscObjectChangeTypeName((PetscObject)viewer,type);
439:   (*r)(viewer);
440:   return(0);
441: }

443: /*@C
444:    PetscViewerRegister - Adds a viewer

446:    Not Collective

448:    Input Parameters:
449: +  name_solver - name of a new user-defined viewer
450: -  routine_create - routine to create method context

452:    Level: developer
453:    Notes:
454:    PetscViewerRegister() may be called multiple times to add several user-defined viewers.

456:    Sample usage:
457: .vb
458:    PetscViewerRegister("my_viewer_type",MyViewerCreate);
459: .ve

461:    Then, your solver can be chosen with the procedural interface via
462: $     PetscViewerSetType(viewer,"my_viewer_type")
463:    or at runtime via the option
464: $     -viewer_type my_viewer_type

466:   Concepts: registering^Viewers

468: .seealso: PetscViewerRegisterAll(), PetscViewerRegisterDestroy()
469:  @*/
470: PetscErrorCode  PetscViewerRegister(const char *sname,PetscErrorCode (*function)(PetscViewer))
471: {

475:   PetscFunctionListAdd(&PetscViewerList,sname,function);
476:   return(0);
477: }

479: /*@C
480:    PetscViewerSetFromOptions - Sets the graphics type from the options database.
481:       Defaults to a PETSc X windows graphics.

483:    Collective on PetscViewer

485:    Input Parameter:
486: .     PetscViewer - the graphics context

488:    Level: intermediate

490:    Notes:
491:     Must be called after PetscViewerCreate() before the PetscViewer is used.

493:   Concepts: PetscViewer^setting options

495: .seealso: PetscViewerCreate(), PetscViewerSetType(), PetscViewerType

497: @*/
498: PetscErrorCode  PetscViewerSetFromOptions(PetscViewer viewer)
499: {
500:   PetscErrorCode    ierr;
501:   char              vtype[256];
502:   PetscBool         flg;


507:   if (!PetscViewerList) {
508:     PetscViewerRegisterAll();
509:   }
510:   PetscObjectOptionsBegin((PetscObject)viewer);
511:   PetscOptionsFList("-viewer_type","Type of PetscViewer","None",PetscViewerList,(char*)(((PetscObject)viewer)->type_name ? ((PetscObject)viewer)->type_name : PETSCVIEWERASCII),vtype,256,&flg);
512:   if (flg) {
513:     PetscViewerSetType(viewer,vtype);
514:   }
515:   /* type has not been set? */
516:   if (!((PetscObject)viewer)->type_name) {
517:     PetscViewerSetType(viewer,PETSCVIEWERASCII);
518:   }
519:   if (viewer->ops->setfromoptions) {
520:     (*viewer->ops->setfromoptions)(PetscOptionsObject,viewer);
521:   }

523:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
524:   PetscObjectProcessOptionsHandlers(PetscOptionsObject,(PetscObject)viewer);
525:   PetscViewerViewFromOptions(viewer,NULL,"-viewer_view");
526:   PetscOptionsEnd();
527:   return(0);
528: }

530: PetscErrorCode PetscViewerFlowControlStart(PetscViewer viewer,PetscInt *mcnt,PetscInt *cnt)
531: {
534:   PetscViewerBinaryGetFlowControl(viewer,mcnt);
535:   PetscViewerBinaryGetFlowControl(viewer,cnt);
536:   return(0);
537: }

539: PetscErrorCode PetscViewerFlowControlStepMaster(PetscViewer viewer,PetscInt i,PetscInt *mcnt,PetscInt cnt)
540: {
542:   MPI_Comm       comm;

545:   PetscObjectGetComm((PetscObject)viewer,&comm);
546:   if (i >= *mcnt) {
547:     *mcnt += cnt;
548:     MPI_Bcast(mcnt,1,MPIU_INT,0,comm);
549:   }
550:   return(0);
551: }

553: PetscErrorCode PetscViewerFlowControlEndMaster(PetscViewer viewer,PetscInt *mcnt)
554: {
556:   MPI_Comm       comm;
558:   PetscObjectGetComm((PetscObject)viewer,&comm);
559:   *mcnt = 0;
560:   MPI_Bcast(mcnt,1,MPIU_INT,0,comm);
561:   return(0);
562: }

564: PetscErrorCode PetscViewerFlowControlStepWorker(PetscViewer viewer,PetscMPIInt rank,PetscInt *mcnt)
565: {
567:   MPI_Comm       comm;
569:   PetscObjectGetComm((PetscObject)viewer,&comm);
570:   while (PETSC_TRUE) {
571:     if (rank < *mcnt) break;
572:     MPI_Bcast(mcnt,1,MPIU_INT,0,comm);
573:   }
574:   return(0);
575: }

577: PetscErrorCode PetscViewerFlowControlEndWorker(PetscViewer viewer,PetscInt *mcnt)
578: {
580:   MPI_Comm       comm;
582:   PetscObjectGetComm((PetscObject)viewer,&comm);
583:   while (PETSC_TRUE) {
584:     MPI_Bcast(mcnt,1,MPIU_INT,0,comm);
585:     if (!*mcnt) break;
586:   }
587:   return(0);
588: }