Floating Point Error Detection using Fortran API

An illustrative code example in F90 using the available inf/nan tests is shown below (and is also available in the examples directory from a top-level install).

!!-----------------------------------------------------------------------bl-
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!! 
!! libGRVY - a utility library for scientific computing.
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!!
!! math.f90: Fortran example illustrating inf/nan math tests.
!!
!!--------------------------------------------------------------------------
!!--------------------------------------------------------------------------
 
program test_isnan_isinf
 
  use grvy
 
  implicit none
 
  real*8 :: should_be_nan 
  real*8 :: should_be_inf
 
  real*8 :: m_one, one, zero
 
  integer :: is_nan, is_inf
 
  m_one = -1.d0
  one   =  1.d0
  zero  =  0.d0
 
  should_be_nan = sqrt(m_one)
  should_be_inf = one/zero
 
  call grvy_double_isnan( should_be_nan, is_nan )
  if( is_nan .eq. 1 )then
     write(*,*) "NaN detected"
  endif
 
  call grvy_double_isinf( should_be_inf, is_inf )
  if( is_inf .eq. 1 )then
     write(*,*) "Inf detected"
  endif
 
  call grvy_double_isnan( 5.d0, is_nan )
  if( is_nan .eq. 1 )then
     write(*,*) "NaN detected"
  endif
 
  call grvy_double_isinf( 1.d0, is_inf )
  if( is_inf .eq. 1 )then
     write(*,*) "Inf detected"
  endif
 
  return
 
end program test_isnan_isinf