Program s15ab_t1w_fe
! S15AB_T1W_F Example Program Text
! Mark 30.3 Release. NAG Copyright 2024.
! .. Use Statements ..
Use iso_c_binding, Only: c_ptr
Use nagad_library, Only: nagad_t1w_w_rtype, s15ab_t1w_f, x10aa_t1w_f, &
x10ab_t1w_f, Assignment (=)
Use nag_library, Only: nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Parameters ..
Integer, Parameter :: nout = 6
! .. Local Scalars ..
Type (c_ptr) :: ad_handle
Type (nagad_t1w_w_rtype) :: p, x
Integer :: ifail
! .. Executable Statements ..
Write (nout,*) 'S15AB_T1W_F Example Program Results'
x = -1._nag_wp
Write (nout,*)
Write (nout,*) ' x P(x) dP/dx Exact P'''
! Create AD configuration data object
ifail = 0
Call x10aa_t1w_f(ad_handle,ifail)
x%tangent = 1._nag_wp
ifail = 0
Call s15ab_t1w_f(ad_handle,x,p,ifail)
Write (nout,99999) x%value, p%value, p%tangent, exact_dpdx(x%value)
! Remove computational data object
Call x10ab_t1w_f(ad_handle,ifail)
99999 Format (1X,1P,4E12.3)
Contains
Function exact_dpdx(x_val)
! .. Use Statements ..
Use nag_library, Only: x01aaf
! .. Function Return Value ..
Real (Kind=nag_wp) :: exact_dpdx
! .. Scalar Arguments ..
Real (Kind=nag_wp), Intent (In) :: x_val
! .. Intrinsic Procedures ..
Intrinsic :: exp, sqrt
! .. Executable Statements ..
exact_dpdx = 1._nag_wp/(sqrt(2._nag_wp*x01aaf(x_val)))* &
exp(-x_val**2/2._nag_wp)
Return
End Function exact_dpdx
End Program s15ab_t1w_fe