1: #include <petsc/private/randomimpl.h>

  3: static PetscErrorCode PetscRandomSeed_Rand(PetscRandom r)
  4: {
  5:   PetscFunctionBegin;
  6:   srand((unsigned int)r->seed);
  7:   PetscFunctionReturn(PETSC_SUCCESS);
  8: }

 10: #define RAND_WRAP ((PetscReal)(rand() / (double)((unsigned int)RAND_MAX + 1)))
 11: static PetscErrorCode PetscRandomGetValue_Rand(PetscRandom r, PetscScalar *val)
 12: {
 13:   PetscFunctionBegin;
 14: #if defined(PETSC_USE_COMPLEX)
 15:   if (r->iset) *val = PetscRealPart(r->width) * RAND_WRAP + PetscRealPart(r->low) + (PetscImaginaryPart(r->width) * RAND_WRAP + PetscImaginaryPart(r->low)) * PETSC_i;
 16:   else *val = RAND_WRAP + RAND_WRAP * PETSC_i;
 17: #else
 18:   if (r->iset) *val = r->width * RAND_WRAP + r->low;
 19:   else *val = RAND_WRAP;
 20: #endif
 21:   PetscFunctionReturn(PETSC_SUCCESS);
 22: }

 24: static PetscErrorCode PetscRandomGetValueReal_Rand(PetscRandom r, PetscReal *val)
 25: {
 26:   PetscFunctionBegin;
 27: #if defined(PETSC_USE_COMPLEX)
 28:   if (r->iset) *val = PetscRealPart(r->width) * RAND_WRAP + PetscRealPart(r->low);
 29:   else *val = RAND_WRAP;
 30: #else
 31:   if (r->iset) *val = r->width * RAND_WRAP + r->low;
 32:   else *val = RAND_WRAP;
 33: #endif
 34:   PetscFunctionReturn(PETSC_SUCCESS);
 35: }

 37: static struct _PetscRandomOps PetscRandomOps_Values = {
 38:   PetscDesignatedInitializer(seed, PetscRandomSeed_Rand),
 39:   PetscDesignatedInitializer(getvalue, PetscRandomGetValue_Rand),
 40:   PetscDesignatedInitializer(getvaluereal, PetscRandomGetValueReal_Rand),
 41:   PetscDesignatedInitializer(getvalues, NULL),
 42:   PetscDesignatedInitializer(getvaluesreal, NULL),
 43:   PetscDesignatedInitializer(destroy, NULL),
 44:   PetscDesignatedInitializer(setfromoptions, NULL),
 45: };

 47: /*MC
 48:    PETSCRAND - access to the basic Unix random number generator

 50:    Options Database Key:
 51: . -random_type <rand,rand48,sprng> - set the random number generator from the options database

 53:   Level: beginner

 55:   Note:
 56:   Not recommended since it can produce different numbers on different systems

 58: .seealso: `PetscRandomCreate()`, `PetscRandomSetType()`, `PETSCRAND48`, `PETSCSPRNG`, `PetscRandomSetFromOptions()`, `PetscRandomType`
 59: M*/

 61: PETSC_EXTERN PetscErrorCode PetscRandomCreate_Rand(PetscRandom r)
 62: {
 63:   PetscFunctionBegin;
 64:   r->ops[0] = PetscRandomOps_Values;
 65:   PetscCall(PetscObjectChangeTypeName((PetscObject)r, PETSCRAND));
 66:   PetscFunctionReturn(PETSC_SUCCESS);
 67: }