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

 20: /* Logging support */
 21: PetscCookie  PETSC_RANDOM_COOKIE = 0;

 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 (--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 (rnd->type_name) {
206:     defaultType = 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) {
216:     PetscRandomRegisterAll(PETSC_NULL);
217:   }
218:   PetscOptionsList("-random_type","PetscRandom type","PetscRandomSetType",PetscRandomList,defaultType,typeName,256,&opt);
219:   if (opt) {
220:     PetscRandomSetType(rnd, typeName);
221:   } else {
222:     PetscRandomSetType(rnd, defaultType);
223:   }
224:   return(0);
225: }

229: /*@
230:   PetscRandomSetFromOptions - Configures the random number generator from the options database.

232:   Collective on PetscRandom

234:   Input Parameter:
235: . rnd - The random number generator context

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

240:   Level: beginner

242: .keywords: PetscRandom, set, options, database
243: .seealso: PetscRandomCreate(), PetscRandomSetType()
244: @*/
245: PetscErrorCode  PetscRandomSetFromOptions(PetscRandom rnd)
246: {


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

254:     /* Handle PetscRandom type options */
255:     PetscRandomSetTypeFromOptions_Private(rnd);

257:     /* Handle specific random generator's options */
258:     if (rnd->ops->setfromoptions) {
259:       (*rnd->ops->setfromoptions)(rnd);
260:     }
261:   PetscOptionsEnd();
262:   PetscRandomViewFromOptions(rnd, rnd->name);
263:   return(0);
264: }

268: /*@C
269:    PetscRandomView - Views a random number generator object. 

271:    Collective on PetscRandom

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

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

285:    You can change the format the vector is printed using the 
286:    option PetscViewerSetFormat().

288:    Level: beginner

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

300:   if (!viewer) viewer = PETSC_VIEWER_STDOUT_(rnd->comm);
303:   PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&iascii);
304:   if (iascii) {
305:     PetscMPIInt rank;
306:     MPI_Comm_rank(rnd->comm,&rank);
307:     PetscViewerASCIISynchronizedPrintf(viewer,"[%D] Random type %s, seed %D\n",rank,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(rnd->prefix, "-random_view", &opt);
345:   if (opt) {
346:     PetscOptionsGetString(rnd->prefix, "-random_view", typeName, 1024, &opt);
347:     PetscStrlen(typeName, &len);
348:     if (len > 0) {
349:       PetscViewerCreate(rnd->comm, &viewer);
350:       PetscViewerSetType(viewer, typeName);
351:       PetscOptionsGetString(rnd->prefix, "-random_view_file", fileName, 1024, &opt);
352:       if (opt) {
353:         PetscViewerFileSetName(viewer, fileName);
354:       } else {
355:         PetscViewerFileSetName(viewer, rnd->name);
356:       }
357:       PetscRandomView(rnd, viewer);
358:       PetscViewerFlush(viewer);
359:       PetscViewerDestroy(viewer);
360:     } else {
361:       PetscRandomView(rnd, PETSC_VIEWER_STDOUT_(rnd->comm));
362:     }
363:   }
364:   return(0);
365: }


370: /*@
371:    PetscRandomCreate - Creates a context for generating random numbers,
372:    and initializes the random-number generator.

374:    Collective on MPI_Comm

376:    Input Parameters:
377: +  comm - MPI communicator

379:    Output Parameter:
380: .  r  - the random number generator context

382:    Level: intermediate

384:    Notes:
385:    The random type has to be set by PetscRandomSetType().

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

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

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

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

408:    Concepts: random numbers^creating

410: .seealso: PetscRandomSetType(), PetscRandomGetValue(), PetscRandomGetValueReal(), PetscRandomGetValueImaginary(), PetscRandomSetInterval(), PetscRandomDestroy(), VecSetRandom()
411: @*/

413: PetscErrorCode  PetscRandomCreate(MPI_Comm comm,PetscRandom *r)
414: {
415:   PetscRandom    rr;
417:   PetscMPIInt    rank;

421:   *r = PETSC_NULL;
422: #ifndef PETSC_USE_DYNAMIC_LIBRARIES
423:   PetscRandomInitializePackage(PETSC_NULL);
424: #endif

426:   PetscHeaderCreate(rr,_p_PetscRandom,struct _PetscRandomOps,PETSC_RANDOM_COOKIE,-1,"PetscRandom",comm,PetscRandomDestroy,0);
427:   PetscLogObjectMemory(rr, sizeof(struct _p_PetscRandom));
428:   PetscMemzero(rr->ops, sizeof(struct _PetscRandomOps));
429:   rr->bops->publish = PETSC_NULL;
430:   rr->type_name     = PETSC_NULL;

432:   MPI_Comm_rank(comm,&rank);
433:   rr->data  = PETSC_NULL;
434:   rr->low   = 0.0;
435:   rr->width = 1.0;
436:   rr->iset  = PETSC_FALSE;
437:   rr->seed  = 0x12345678 + 76543*rank;
438:   *r = rr;
439:   return(0);
440: }

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

447:    Not collective

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

452:    Level: intermediate

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

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

461:    Concepts: random numbers^seed

463: .seealso: PetscRandomCreate(), PetscRandomGetSeed(), PetscRandomSetSeed()
464: @*/
465: PetscErrorCode  PetscRandomSeed(PetscRandom r)
466: {


473:   (*r->ops->seed)(r);
474:   PetscObjectStateIncrease((PetscObject)r);
475:   return(0);
476: }

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

484:    Not Collective

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

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

492:    Level: intermediate

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

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

506:    Concepts: random numbers^getting

508: .seealso: PetscRandomCreate(), PetscRandomDestroy(), VecSetRandom()
509: @*/
510: PetscErrorCode  PetscRandomGetValue(PetscRandom r,PetscScalar *val)
511: {


519:   (*r->ops->getvalue)(r,val);
520:   PetscObjectStateIncrease((PetscObject)r);
521:   return(0);
522: }

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

530:    Not Collective

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

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

538:    Level: intermediate

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

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

552:    Concepts: random numbers^getting

554: .seealso: PetscRandomCreate(), PetscRandomDestroy(), VecSetRandom()
555: @*/
556: PetscErrorCode  PetscRandomGetValueReal(PetscRandom r,PetscReal *val)
557: {


565:   (*r->ops->getvaluereal)(r,val);
566:   PetscObjectStateIncrease((PetscObject)r);
567:   return(0);
568: }

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

576:    Not Collective

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

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

584:    Options Database Keys:
585: +    -random_type petscrand48
586: .    -random_type petscrand
587: -    -random_type sprng, uses SPRNG package

589:    Level: intermediate

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

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

603:    Concepts: random numbers^getting

605: .seealso: PetscRandomCreate(), PetscRandomDestroy(), VecSetRandom()
606: @*/
607: PetscErrorCode  PetscRandomGetValueImaginary(PetscRandom r,PetscScalar *val)
608: {


616:   (*r->ops->getvalueimaginary)(r,val);
617:   PetscObjectStateIncrease((PetscObject)r);
618:   return(0);
619: }