1: #include <petscsys.h>
  2: /*@C
  3:       PetscIsInfOrNan - Returns 1 if the input double has an infinity for Not-a-number (Nan) value, otherwise 0.

  5:     Input Parameter:
  6: .     a - the double


  9:      Notes: uses the C99 standard isinf() and isnan() on systems where they exist.
 10:       Otherwises uses ((a - a) != 0.0), note that some optimizing compiles compile
 11:       out this form, thus removing the check.

 13:      Level: beginner
 14: @*/
 15: #if defined(PETSC_USE_REAL___FLOAT128)
 16: PetscErrorCode PetscIsInfOrNanScalar(PetscScalar a)
 17: {
 18:   return isinfq(PetscAbsScalar(a)) || isnanq(PetscAbsScalar(a));
 19: }
 20: PetscErrorCode PetscIsInfOrNanReal(PetscReal a)
 21: {
 22:   return isinfq(a) || isnanq(a);
 23: }
 24: #elif defined(PETSC_HAVE_ISINF) && defined(PETSC_HAVE_ISNAN)
 25: PetscErrorCode PetscIsInfOrNanScalar(PetscScalar a)
 26: {
 27:   return isinf(PetscAbsScalar(a)) || isnan(PetscAbsScalar(a));
 28: }
 29: PetscErrorCode PetscIsInfOrNanReal(PetscReal a)
 30: {
 31:   return isinf(a) || isnan(a);
 32: }
 33: #elif defined(PETSC_HAVE__FINITE) && defined(PETSC_HAVE__ISNAN)
 34: #if defined(PETSC_HAVE_FLOAT_H)
 35: #include "float.h"  /* Microsoft Windows defines _finite() in float.h */
 36: #endif
 37: #if defined(PETSC_HAVE_IEEEFP_H)
 38: #include "ieeefp.h"  /* Solaris prototypes these here */
 39: #endif
 40: PetscErrorCode PetscIsInfOrNanScalar(PetscScalar a)
 41: {
 42:   return !_finite(PetscAbsScalar(a)) || _isnan(PetscAbsScalar(a));
 43: }
 44: PetscErrorCode PetscIsInfOrNanReal(PetscReal a)
 45: {
 46:   return !_finite(a) || _isnan(a);
 47: }
 48: #else
 49: PetscErrorCode PetscIsInfOrNanScalar(PetscScalar a)
 50: {
 51:   return  ((a - a) != (PetscScalar)0);
 52: }
 53: PetscErrorCode PetscIsInfOrNanReal(PetscReal a)
 54: {
 55:   return ((a - a) != 0);
 56: }
 57: #endif