10039db0dSBarry Smith #define PETSC_DESIRE_FEATURE_TEST_MACROS /* for drand48() */ 2d6cc7855SJacob Faibussowitsch #include <petsc/private/randomimpl.h> 35c6c1daeSBarry Smith 466976f2fSJacob Faibussowitsch static PetscErrorCode PetscRandomSeed_Rand48(PetscRandom r) 5d71ae5a4SJacob Faibussowitsch { 65c6c1daeSBarry Smith PetscFunctionBegin; 75c6c1daeSBarry Smith srand48(r->seed); 83ba16761SJacob Faibussowitsch PetscFunctionReturn(PETSC_SUCCESS); 95c6c1daeSBarry Smith } 105c6c1daeSBarry Smith 1166976f2fSJacob Faibussowitsch static PetscErrorCode PetscRandomGetValue_Rand48(PetscRandom r, PetscScalar *val) 12d71ae5a4SJacob Faibussowitsch { 135c6c1daeSBarry Smith PetscFunctionBegin; 145c6c1daeSBarry Smith #if defined(PETSC_USE_COMPLEX) 155c6c1daeSBarry Smith if (r->iset) { 16b0043f70SBarry Smith *val = PetscRealPart(r->width) * (PetscReal)drand48() + PetscRealPart(r->low) + (PetscImaginaryPart(r->width) * (PetscReal)drand48() + PetscImaginaryPart(r->low)) * PETSC_i; 175c6c1daeSBarry Smith } else { 185c6c1daeSBarry Smith *val = (PetscReal)drand48() + (PetscReal)drand48() * PETSC_i; 195c6c1daeSBarry Smith } 205c6c1daeSBarry Smith #else 21*6497c311SBarry Smith if (r->iset) *val = r->width * drand48() + (PetscReal)r->low; 225c6c1daeSBarry Smith else *val = drand48(); 235c6c1daeSBarry Smith #endif 243ba16761SJacob Faibussowitsch PetscFunctionReturn(PETSC_SUCCESS); 255c6c1daeSBarry Smith } 265c6c1daeSBarry Smith 2766976f2fSJacob Faibussowitsch static PetscErrorCode PetscRandomGetValueReal_Rand48(PetscRandom r, PetscReal *val) 28d71ae5a4SJacob Faibussowitsch { 295c6c1daeSBarry Smith PetscFunctionBegin; 305c6c1daeSBarry Smith #if defined(PETSC_USE_COMPLEX) 315c6c1daeSBarry Smith if (r->iset) *val = PetscRealPart(r->width) * drand48() + PetscRealPart(r->low); 325c6c1daeSBarry Smith else *val = drand48(); 335c6c1daeSBarry Smith #else 34*6497c311SBarry Smith if (r->iset) *val = r->width * (PetscReal)drand48() + (PetscReal)r->low; 35*6497c311SBarry Smith else *val = (PetscReal)drand48(); 365c6c1daeSBarry Smith #endif 373ba16761SJacob Faibussowitsch PetscFunctionReturn(PETSC_SUCCESS); 385c6c1daeSBarry Smith } 395c6c1daeSBarry Smith 405c6c1daeSBarry Smith static struct _PetscRandomOps PetscRandomOps_Values = { 41267267bdSJacob Faibussowitsch PetscDesignatedInitializer(seed, PetscRandomSeed_Rand48), 42267267bdSJacob Faibussowitsch PetscDesignatedInitializer(getvalue, PetscRandomGetValue_Rand48), 43267267bdSJacob Faibussowitsch PetscDesignatedInitializer(getvaluereal, PetscRandomGetValueReal_Rand48), 445c6c1daeSBarry Smith }; 455c6c1daeSBarry Smith 465c6c1daeSBarry Smith /*MC 47c31d2375SBarry Smith PETSCRAND48 - access to the basic Unix `drand48()` random number generator 485c6c1daeSBarry Smith 49c31d2375SBarry Smith Options Database Key: 501179163eSBarry Smith . -random_type <rand,rand48,sprng> - select the random number generator at runtime 515c6c1daeSBarry Smith 525c6c1daeSBarry Smith Level: beginner 535c6c1daeSBarry Smith 54811af0c4SBarry Smith Note: 551179163eSBarry Smith Not recommended because it may produce different results on different systems. 561179163eSBarry Smith 571179163eSBarry Smith .seealso: `PetscRandomCreate()`, `PetscRandomSetType()`, `PETSCRAND`, `PETSCSPRNG`, `PetscRandomSetFromOptions()` 585c6c1daeSBarry Smith M*/ 595c6c1daeSBarry Smith 60d71ae5a4SJacob Faibussowitsch PETSC_EXTERN PetscErrorCode PetscRandomCreate_Rand48(PetscRandom r) 61d71ae5a4SJacob Faibussowitsch { 625c6c1daeSBarry Smith PetscFunctionBegin; 63aea10558SJacob Faibussowitsch r->ops[0] = PetscRandomOps_Values; 649566063dSJacob Faibussowitsch PetscCall(PetscObjectChangeTypeName((PetscObject)r, PETSCRAND48)); 653ba16761SJacob Faibussowitsch PetscFunctionReturn(PETSC_SUCCESS); 665c6c1daeSBarry Smith } 67