1: #define PETSC_DESIRE_FEATURE_TEST_MACROS /* for drand48() */
  2: #include <petsc/private/randomimpl.h>

  4: PetscErrorCode  PetscRandomSeed_Rand48(PetscRandom r)
  5: {
  6:   srand48(r->seed);
  7:   return 0;
  8: }

 10: PetscErrorCode  PetscRandomGetValue_Rand48(PetscRandom r,PetscScalar *val)
 11: {
 12: #if defined(PETSC_USE_COMPLEX)
 13:   if (r->iset) {
 14:     *val = PetscRealPart(r->width)*(PetscReal)drand48() + PetscRealPart(r->low) + (PetscImaginaryPart(r->width)*(PetscReal)drand48() + PetscImaginaryPart(r->low)) * PETSC_i;
 15:   } else {
 16:     *val = (PetscReal)drand48() + (PetscReal)drand48()*PETSC_i;
 17:   }
 18: #else
 19:   if (r->iset) *val = r->width * drand48() + r->low;
 20:   else         *val = drand48();
 21: #endif
 22:   return 0;
 23: }

 25: PetscErrorCode  PetscRandomGetValueReal_Rand48(PetscRandom r,PetscReal *val)
 26: {
 27: #if defined(PETSC_USE_COMPLEX)
 28:   if (r->iset) *val = PetscRealPart(r->width)*drand48() + PetscRealPart(r->low);
 29:   else         *val = drand48();
 30: #else
 31:   if (r->iset) *val = r->width * drand48() + r->low;
 32:   else         *val = drand48();
 33: #endif
 34:   return 0;
 35: }

 37: static struct _PetscRandomOps PetscRandomOps_Values = {
 38:   PetscDesignatedInitializer(seed,PetscRandomSeed_Rand48),
 39:   PetscDesignatedInitializer(getvalue,PetscRandomGetValue_Rand48),
 40:   PetscDesignatedInitializer(getvaluereal,PetscRandomGetValueReal_Rand48),
 41: };

 43: /*MC
 44:    PETSCRAND48 - access to the basic Unix drand48() random number generator

 46:    Options Database Keys:
 47: . -random_type <rand,rand48,sprng>

 49:   Level: beginner

 51: .seealso: PetscRandomCreate(), PetscRandomSetType(), PETSCRAND, PETSCSPRNG
 52: M*/

 54: PETSC_EXTERN PetscErrorCode PetscRandomCreate_Rand48(PetscRandom r)
 55: {
 56:   PetscMemcpy(r->ops,&PetscRandomOps_Values,sizeof(PetscRandomOps_Values));
 57:   PetscObjectChangeTypeName((PetscObject)r,PETSCRAND48);
 58:   return 0;
 59: }