Actual source code: random.c

  1: #define PETSC_DLL
  2: /*
  3:     This file contains routines for interfacing to random number generators.
  4:     This provides more than just an interface to some system random number
  5:     generator:

  7:     Numbers can be shuffled for use as random tuples

  9:     Multiple random number generators may be used

 11:     We are still not sure what interface we want here.  There should be
 12:     one to reinitialize and set the seed.
 13:  */

 15:  #include ../src/sys/random/randomimpl.h
 16: #if defined (PETSC_HAVE_STDLIB_H)
 17: #include <stdlib.h>
 18: #endif

 20: /* Logging support */
 21: PetscCookie  PETSC_RANDOM_COOKIE;

 25: /*@
 26:    PetscRandomDestroy - Destroys a context that has been formed by 
 27:    PetscRandomCreate().

 29:    Collective on PetscRandom

 31:    Intput Parameter:
 32: .  r  - the random number generator context

 34:    Level: intermediate

 36: .seealso: PetscRandomGetValue(), PetscRandomCreate(), VecSetRandom()
 37: @*/
 38: PetscErrorCode  PetscRandomDestroy(PetscRandom r)
 39: {
 43:   if (--((PetscObject)r)->refct > 0) return(0);
 44:   PetscHeaderDestroy(r);
 45:   return(0);
 46: }

 50: /*@C
 51:    PetscRandomGetInterval - Gets the interval over which the random numbers
 52:    will be randomly distributed.  By default, this interval is [0,1).

 54:    Not collective

 56:    Input Parameters:
 57: .  r  - the random number generator context

 59:    Output Parameters:
 60: +  low - The lower bound of the interval
 61: -  high - The upper bound of the interval

 63:    Level: intermediate

 65:    Concepts: random numbers^range

 67: .seealso: PetscRandomCreate(), PetscRandomSetInterval()
 68: @*/
 69: PetscErrorCode  PetscRandomGetInterval(PetscRandom r,PetscScalar *low,PetscScalar *high)
 70: {
 73:   if (low) {
 75:     *low = r->low;
 76:   }
 77:   if (high) {
 79:     *high = r->low+r->width;
 80:   }
 81:   return(0);
 82: }

 86: /*@C
 87:    PetscRandomSetInterval - Sets the interval over which the random numbers
 88:    will be randomly distributed.  By default, this interval is [0,1).

 90:    Not collective

 92:    Input Parameters:
 93: +  r  - the random number generator context
 94: .  low - The lower bound of the interval
 95: -  high - The upper bound of the interval

 97:    Level: intermediate

 99:    Concepts: random numbers^range

101: .seealso: PetscRandomCreate(), PetscRandomGetInterval()
102: @*/
103: PetscErrorCode  PetscRandomSetInterval(PetscRandom r,PetscScalar low,PetscScalar high)
104: {
107: #if defined(PETSC_USE_COMPLEX)
108:   if (PetscRealPart(low) >= PetscRealPart(high))           SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"only low < high");
109:   if (PetscImaginaryPart(low) >= PetscImaginaryPart(high)) SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"only low < high");
110: #else
111:   if (low >= high) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"only low < high: Instead %G %G",low,high);
112: #endif
113:   r->low   = low;
114:   r->width = high-low;
115:   r->iset  = PETSC_TRUE;
116:   return(0);
117: }

121: /*@C
122:    PetscRandomGetSeed - Gets the random seed.

124:    Not collective

126:    Input Parameters:
127: .  r - The random number generator context

129:    Output Parameter:
130: .  seed - The random seed

132:    Level: intermediate

134:    Concepts: random numbers^seed

136: .seealso: PetscRandomCreate(), PetscRandomSetSeed(), PetscRandomSeed()
137: @*/
138: PetscErrorCode  PetscRandomGetSeed(PetscRandom r,unsigned long *seed)
139: {
142:   if (seed) {
144:     *seed = r->seed;
145:   }
146:   return(0);
147: }

151: /*@C
152:    PetscRandomSetSeed - Sets the random seed.

154:    Not collective

156:    Input Parameters:
157: +  r  - The random number generator context
158: -  seed - The random seed

160:    Level: intermediate

162:    Usage:
163:       PetscRandomSetSeed(r,a positive integer);
164:       PetscRandomSeed(r);  PetscRandomGetValue() will now start with the new seed.

166:       PetscRandomSeed(r) without a call to PetscRandomSetSeed() re-initializes
167:         the seed. The random numbers generated will be the same as before.

169:    Concepts: random numbers^seed

171: .seealso: PetscRandomCreate(), PetscRandomGetSeed(), PetscRandomSeed()
172: @*/
173: PetscErrorCode  PetscRandomSetSeed(PetscRandom r,unsigned long seed)
174: {
177:   r->seed = seed;
178:   return(0);
179: }

181: /* ------------------------------------------------------------------- */
184: /*
185:   PetscRandomSetTypeFromOptions_Private - Sets the type of random generator from user options. Defaults to type PETSCRAND48 or PETSCRAND.

187:   Collective on PetscRandom

189:   Input Parameter:
190: . rnd - The random number generator context

192:   Level: intermediate

194: .keywords: PetscRandom, set, options, database, type
195: .seealso: PetscRandomSetFromOptions(), PetscRandomSetType()
196: */
197: static PetscErrorCode PetscRandomSetTypeFromOptions_Private(PetscRandom rnd)
198: {
199:   PetscTruth     opt;
200:   const char     *defaultType;
201:   char           typeName[256];

205:   if (((PetscObject)rnd)->type_name) {
206:     defaultType = ((PetscObject)rnd)->type_name;
207:   } else {
208: #if defined(PETSC_HAVE_DRAND48)    
209:     defaultType = PETSCRAND48;
210: #elif defined(PETSC_HAVE_RAND)
211:     defaultType = PETSCRAND;
212: #endif
213:   }

215:   if (!PetscRandomRegisterAllCalled) {PetscRandomRegisterAll(PETSC_NULL);}
216:   PetscOptionsList("-random_type","PetscRandom type","PetscRandomSetType",PetscRandomList,defaultType,typeName,256,&opt);
217:   if (opt) {
218:     PetscRandomSetType(rnd, typeName);
219:   } else {
220:     PetscRandomSetType(rnd, defaultType);
221:   }
222:   return(0);
223: }

227: /*@
228:   PetscRandomSetFromOptions - Configures the random number generator from the options database.

230:   Collective on PetscRandom

232:   Input Parameter:
233: . rnd - The random number generator context

235:   Notes:  To see all options, run your program with the -help option, or consult the users manual.
236:           Must be called after PetscRandomCreate() but before the rnd is used.

238:   Level: beginner

240: .keywords: PetscRandom, set, options, database
241: .seealso: PetscRandomCreate(), PetscRandomSetType()
242: @*/
243: PetscErrorCode  PetscRandomSetFromOptions(PetscRandom rnd)
244: {


250:   PetscOptionsBegin(((PetscObject)rnd)->comm, ((PetscObject)rnd)->prefix, "PetscRandom options", "PetscRandom");

252:     /* Handle PetscRandom type options */
253:     PetscRandomSetTypeFromOptions_Private(rnd);

255:     /* Handle specific random generator's options */
256:     if (rnd->ops->setfromoptions) {
257:       (*rnd->ops->setfromoptions)(rnd);
258:     }
259:   PetscOptionsEnd();
260:   PetscRandomViewFromOptions(rnd, ((PetscObject)rnd)->name);
261:   return(0);
262: }

266: /*@C
267:    PetscRandomView - Views a random number generator object. 

269:    Collective on PetscRandom

271:    Input Parameters:
272: +  rnd - The random number generator context
273: -  viewer - an optional visualization context

275:    Notes:
276:    The available visualization contexts include
277: +     PETSC_VIEWER_STDOUT_SELF - standard output (default)
278: -     PETSC_VIEWER_STDOUT_WORLD - synchronized standard
279:          output where only the first processor opens
280:          the file.  All other processors send their 
281:          data to the first processor to print. 

283:    You can change the format the vector is printed using the 
284:    option PetscViewerSetFormat().

286:    Level: beginner

288: .seealso:  PetscRealView(), PetscScalarView(), PetscIntView()
289: @*/
290: PetscErrorCode  PetscRandomView(PetscRandom rnd,PetscViewer viewer)
291: {
292:   PetscErrorCode    ierr;
293:   PetscTruth        iascii;

298:   if (!viewer) {
299:     PetscViewerASCIIGetStdout(((PetscObject)rnd)->comm,&viewer);
300:   }
303:   PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&iascii);
304:   if (iascii) {
305:     PetscMPIInt rank;
306:     MPI_Comm_rank(((PetscObject)rnd)->comm,&rank);
307:     PetscViewerASCIISynchronizedPrintf(viewer,"[%D] Random type %s, seed %D\n",rank,((PetscObject)rnd)->type_name,rnd->seed);
308:     PetscViewerFlush(viewer);
309:   } else {
310:     const char *tname;
311:     PetscObjectGetName((PetscObject)viewer,&tname);
312:     SETERRQ1(PETSC_ERR_SUP,"Viewer type %s not supported for this object",tname);
313:   }
314:   return(0);
315: }

317: #undef  __FUNCT__
319: /*@
320:   PetscRandomViewFromOptions - This function visualizes the type and the seed of the generated random numbers based upon user options.

322:   Collective on PetscRandom

324:   Input Parameters:
325: . rnd   - The random number generator context
326: . title - The title

328:   Level: intermediate

330: .keywords: PetscRandom, view, options, database
331: .seealso: PetscRandomSetFromOptions()
332: @*/
333: PetscErrorCode  PetscRandomViewFromOptions(PetscRandom rnd, char *title)
334: {
335:   PetscTruth     opt;
336:   PetscViewer    viewer;
337:   char           typeName[1024];
338:   char           fileName[PETSC_MAX_PATH_LEN];
339:   size_t         len;
340: 

344:   PetscOptionsHasName(((PetscObject)rnd)->prefix, "-random_view", &opt);
345:   if (opt) {
346:     PetscOptionsGetString(((PetscObject)rnd)->prefix, "-random_view", typeName, 1024, &opt);
347:     PetscStrlen(typeName, &len);
348:     if (len > 0) {
349:       PetscViewerCreate(((PetscObject)rnd)->comm, &viewer);
350:       PetscViewerSetType(viewer, typeName);
351:       PetscOptionsGetString(((PetscObject)rnd)->prefix, "-random_view_file", fileName, 1024, &opt);
352:       if (opt) {
353:         PetscViewerFileSetName(viewer, fileName);
354:       } else {
355:         PetscViewerFileSetName(viewer, ((PetscObject)rnd)->name);
356:       }
357:       PetscRandomView(rnd, viewer);
358:       PetscViewerFlush(viewer);
359:       PetscViewerDestroy(viewer);
360:     } else {
361:       PetscViewer viewer;
362:       PetscViewerASCIIGetStdout(((PetscObject)rnd)->comm,&viewer);
363:       PetscRandomView(rnd, viewer);
364:     }
365:   }
366:   return(0);
367: }


372: /*@
373:    PetscRandomCreate - Creates a context for generating random numbers,
374:    and initializes the random-number generator.

376:    Collective on MPI_Comm

378:    Input Parameters:
379: +  comm - MPI communicator

381:    Output Parameter:
382: .  r  - the random number generator context

384:    Level: intermediate

386:    Notes:
387:    The random type has to be set by PetscRandomSetType().

389:    This is only a primative "parallel" random number generator, it should NOT
390:    be used for sophisticated parallel Monte Carlo methods since it will very likely
391:    not have the correct statistics across processors. You can provide your own
392:    parallel generator using PetscRandomRegister();

394:    If you create a PetscRandom() using PETSC_COMM_SELF on several processors then
395:    the SAME random numbers will be generated on all those processors. Use PETSC_COMM_WORLD
396:    or the appropriate parallel communicator to eliminate this issue.

398:    Use VecSetRandom() to set the elements of a vector to random numbers.

400:    Example of Usage:
401: .vb
402:       PetscRandomCreate(PETSC_COMM_SELF,&r);
403:       PetscRandomSetType(r,PETSCRAND48);
404:       PetscRandomGetValue(r,&value1);
405:       PetscRandomGetValueReal(r,&value2);
406:       PetscRandomGetValueImaginary(r,&value3);
407:       PetscRandomDestroy(r);
408: .ve

410:    Concepts: random numbers^creating

412: .seealso: PetscRandomSetType(), PetscRandomGetValue(), PetscRandomGetValueReal(), PetscRandomGetValueImaginary(), PetscRandomSetInterval(), 
413:           PetscRandomDestroy(), VecSetRandom(), PetscRandomType
414: @*/

416: PetscErrorCode  PetscRandomCreate(MPI_Comm comm,PetscRandom *r)
417: {
418:   PetscRandom    rr;
420:   PetscMPIInt    rank;

424:   *r = PETSC_NULL;
425: #ifndef PETSC_USE_DYNAMIC_LIBRARIES
426:   PetscRandomInitializePackage(PETSC_NULL);
427: #endif

429:   PetscHeaderCreate(rr,_p_PetscRandom,struct _PetscRandomOps,PETSC_RANDOM_COOKIE,-1,"PetscRandom",comm,PetscRandomDestroy,0);

431:   MPI_Comm_rank(comm,&rank);
432:   rr->data  = PETSC_NULL;
433:   rr->low   = 0.0;
434:   rr->width = 1.0;
435:   rr->iset  = PETSC_FALSE;
436:   rr->seed  = 0x12345678 + 76543*rank;
437:   *r = rr;
438:   return(0);
439: }

443: /*@C
444:    PetscRandomSeed - Seed the generator.

446:    Not collective

448:    Input Parameters:
449: .  r - The random number generator context

451:    Level: intermediate

453:    Usage:
454:       PetscRandomSetSeed(r,a positive integer);
455:       PetscRandomSeed(r);  PetscRandomGetValue() will now start with the new seed.

457:       PetscRandomSeed(r) without a call to PetscRandomSetSeed() re-initializes
458:         the seed. The random numbers generated will be the same as before.

460:    Concepts: random numbers^seed

462: .seealso: PetscRandomCreate(), PetscRandomGetSeed(), PetscRandomSetSeed()
463: @*/
464: PetscErrorCode  PetscRandomSeed(PetscRandom r)
465: {


472:   (*r->ops->seed)(r);
473:   PetscObjectStateIncrease((PetscObject)r);
474:   return(0);
475: }

479: /*@
480:    PetscRandomGetValue - Generates a random number.  Call this after first calling
481:    PetscRandomCreate().

483:    Not Collective

485:    Intput Parameter:
486: .  r  - the random number generator context

488:    Output Parameter:
489: .  val - the value

491:    Level: intermediate

493:    Notes:
494:    Use VecSetRandom() to set the elements of a vector to random numbers.

496:    Example of Usage:
497: .vb
498:       PetscRandomCreate(PETSC_COMM_WORLD,&r);
499:       PetscRandomGetValue(r,&value1);
500:       PetscRandomGetValue(r,&value2);
501:       PetscRandomGetValue(r,&value3);
502:       PetscRandomDestroy(r);
503: .ve

505:    Concepts: random numbers^getting

507: .seealso: PetscRandomCreate(), PetscRandomDestroy(), VecSetRandom()
508: @*/
509: PetscErrorCode  PetscRandomGetValue(PetscRandom r,PetscScalar *val)
510: {


518:   (*r->ops->getvalue)(r,val);
519:   PetscObjectStateIncrease((PetscObject)r);
520:   return(0);
521: }

525: /*@
526:    PetscRandomGetValueReal - Generates a random number.  Call this after first calling
527:    PetscRandomCreate().

529:    Not Collective

531:    Intput Parameter:
532: .  r  - the random number generator context

534:    Output Parameter:
535: .  val - the value

537:    Level: intermediate

539:    Notes:
540:    Use VecSetRandom() to set the elements of a vector to random numbers.

542:    Example of Usage:
543: .vb
544:       PetscRandomCreate(PETSC_COMM_WORLD,&r);
545:       PetscRandomGetValueReal(r,&value1);
546:       PetscRandomGetValueReal(r,&value2);
547:       PetscRandomGetValueReal(r,&value3);
548:       PetscRandomDestroy(r);
549: .ve

551:    Concepts: random numbers^getting

553: .seealso: PetscRandomCreate(), PetscRandomDestroy(), VecSetRandom()
554: @*/
555: PetscErrorCode  PetscRandomGetValueReal(PetscRandom r,PetscReal *val)
556: {


564:   (*r->ops->getvaluereal)(r,val);
565:   PetscObjectStateIncrease((PetscObject)r);
566:   return(0);
567: }

571: /*@
572:    PetscRandomGetValueImaginary - Generates a random number.  Call this after first calling
573:    PetscRandomCreate().

575:    Not Collective

577:    Intput Parameter:
578: .  r  - the random number generator context

580:    Output Parameter:
581: .  val - the value

583:    Options Database Keys:
584: +    -random_type rand48
585: .    -random_type rand
586: -    -random_type sprng, uses SPRNG package

588:    Level: intermediate

590:    Notes:
591:    Use VecSetRandom() to set the elements of a vector to random numbers.

593:    Example of Usage:
594: .vb
595:       PetscRandomCreate(PETSC_COMM_WORLD,&r);
596:       PetscRandomGetValueImaginary(r,&value1);
597:       PetscRandomGetValueImaginary(r,&value2);
598:       PetscRandomGetValueImaginary(r,&value3);
599:       PetscRandomDestroy(r);
600: .ve

602:    Concepts: random numbers^getting

604: .seealso: PetscRandomCreate(), PetscRandomDestroy(), VecSetRandom()
605: @*/
606: PetscErrorCode  PetscRandomGetValueImaginary(PetscRandom r,PetscScalar *val)
607: {


615:   (*r->ops->getvalueimaginary)(r,val);
616:   PetscObjectStateIncrease((PetscObject)r);
617:   return(0);
618: }