1 #define PETSC_DESIRE_FEATURE_TEST_MACROS /* for drand48() */ 2 #include <petsc/private/randomimpl.h> 3 4 static PetscErrorCode PetscRandomSeed_Rand48(PetscRandom r) 5 { 6 PetscFunctionBegin; 7 srand48(r->seed); 8 PetscFunctionReturn(PETSC_SUCCESS); 9 } 10 11 static PetscErrorCode PetscRandomGetValue_Rand48(PetscRandom r, PetscScalar *val) 12 { 13 PetscFunctionBegin; 14 #if defined(PETSC_USE_COMPLEX) 15 if (r->iset) { 16 *val = PetscRealPart(r->width) * (PetscReal)drand48() + PetscRealPart(r->low) + (PetscImaginaryPart(r->width) * (PetscReal)drand48() + PetscImaginaryPart(r->low)) * PETSC_i; 17 } else { 18 *val = (PetscReal)drand48() + (PetscReal)drand48() * PETSC_i; 19 } 20 #else 21 if (r->iset) *val = r->width * drand48() + (PetscReal)r->low; 22 else *val = drand48(); 23 #endif 24 PetscFunctionReturn(PETSC_SUCCESS); 25 } 26 27 static PetscErrorCode PetscRandomGetValueReal_Rand48(PetscRandom r, PetscReal *val) 28 { 29 PetscFunctionBegin; 30 #if defined(PETSC_USE_COMPLEX) 31 if (r->iset) *val = PetscRealPart(r->width) * drand48() + PetscRealPart(r->low); 32 else *val = drand48(); 33 #else 34 if (r->iset) *val = r->width * (PetscReal)drand48() + (PetscReal)r->low; 35 else *val = (PetscReal)drand48(); 36 #endif 37 PetscFunctionReturn(PETSC_SUCCESS); 38 } 39 40 static struct _PetscRandomOps PetscRandomOps_Values = { 41 PetscDesignatedInitializer(seed, PetscRandomSeed_Rand48), 42 PetscDesignatedInitializer(getvalue, PetscRandomGetValue_Rand48), 43 PetscDesignatedInitializer(getvaluereal, PetscRandomGetValueReal_Rand48), 44 }; 45 46 /*MC 47 PETSCRAND48 - access to the basic Unix `drand48()` random number generator 48 49 Options Database Key: 50 . -random_type <rand,rand48,sprng> - select the random number generator at runtime 51 52 Level: beginner 53 54 Note: 55 Not recommended because it may produce different results on different systems. 56 57 .seealso: `PetscRandomCreate()`, `PetscRandomSetType()`, `PETSCRAND`, `PETSCSPRNG`, `PetscRandomSetFromOptions()` 58 M*/ 59 60 PETSC_EXTERN PetscErrorCode PetscRandomCreate_Rand48(PetscRandom r) 61 { 62 PetscFunctionBegin; 63 r->ops[0] = PetscRandomOps_Values; 64 PetscCall(PetscObjectChangeTypeName((PetscObject)r, PETSCRAND48)); 65 PetscFunctionReturn(PETSC_SUCCESS); 66 } 67