! D01BD_A1W_F Example Program Text
! Mark 30.1 Release. NAG Copyright 2024.
Module d01bd_a1w_fe_mod
! .. Use Statements ..
Use iso_c_binding, Only: c_ptr
Use nagad_library, Only: nagad_a1w_w_rtype, sin, Assignment (=), &
Operator (**), Operator (*)
Use nag_library, Only: nag_wp, x01aaf
! .. Implicit None Statement ..
Implicit None
! .. Accessibility Statements ..
Private
Public :: f_a1w
! .. Parameters ..
Integer, Parameter, Public :: nout = 6
Contains
Subroutine f_a1w(ad_handle,x,ret,iuser,ruser)
! .. Scalar Arguments ..
Type (c_ptr), Intent (Inout) :: ad_handle
Type (nagad_a1w_w_rtype), Intent (Out) :: ret
Type (nagad_a1w_w_rtype), Intent (In) :: x
! .. Array Arguments ..
Type (nagad_a1w_w_rtype), Intent (Inout) :: ruser(*)
Integer, Intent (Inout) :: iuser(*)
! .. Local Scalars ..
Real (Kind=nag_wp) :: pi, xx
! .. Executable Statements ..
pi = x01aaf(xx)
ret = (x**2)*sin(pi*ruser(1)*x)
Return
End Subroutine f_a1w
End Module d01bd_a1w_fe_mod
Program d01bd_a1w_fe
! D01BD_A1W_F Example Main Program
! .. Use Statements ..
Use d01bd_a1w_fe_mod, Only: f_a1w, nout
Use iso_c_binding, Only: c_ptr
Use nagad_library, Only: abs, d01bd_a1w_f, max, &
nagad_a1w_get_derivative, &
nagad_a1w_inc_derivative, &
nagad_a1w_ir_interpret_adjoint_sparse, &
nagad_a1w_ir_register_variable, &
nagad_a1w_ir_remove, nagad_a1w_w_rtype, &
x10aa_a1w_f, x10ab_a1w_f, x10za_a1w_f, &
Assignment (=), Operator (>), Operator (*)
Use nag_library, Only: nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Local Scalars ..
Type (nagad_a1w_w_rtype) :: a, abserr, b, epsabs, epsrel, result
Type (c_ptr) :: ad_handle
Real (Kind=nag_wp) :: dr
Integer :: ifail
! .. Local Arrays ..
Type (nagad_a1w_w_rtype) :: ruser(1)
Integer :: iuser(1)
! .. Executable Statements ..
Write (nout,*) 'D01BD_A1W_F Example Program Results'
epsabs = 0.0_nag_wp
epsrel = 1.0E-4_nag_wp
a = 0.0_nag_wp
b = 1.0_nag_wp
ruser(1) = 10.0_nag_wp
! Create AD tape
Call x10za_a1w_f
! Create AD configuration data object
ifail = 0
Call x10aa_a1w_f(ad_handle,ifail)
! Register variables to differentiate w.r.t.
Call nagad_a1w_ir_register_variable(ruser(1))
ifail = 0
Call d01bd_a1w_f(ad_handle,f_a1w,a,b,epsabs,epsrel,result,abserr,iuser, &
ruser,ifail)
Call nagad_a1w_inc_derivative(result,1.0E0_nag_wp)
Call nagad_a1w_ir_interpret_adjoint_sparse(ifail)
Write (nout,*)
Write (nout,*) ' Derivatives calculated: First order adjoints'
Write (nout,*) ' Computational mode : algorithmic'
! Get derivative
dr = nagad_a1w_get_derivative(ruser(1))
Write (nout,*)
Write (nout,99999) 'a - lower limit of integration = ', a%value
Write (nout,99999) 'b - upper limit of integration = ', b%value
Write (nout,99998) 'epsabs - absolute accuracy requested = ', &
epsabs%value
Write (nout,99998) 'epsrel - relative accuracy requested = ', &
epsrel%value
Write (nout,*)
Write (nout,99997) 'result - approximation to the integral = ', &
result%value
Write (nout,99998) 'abserr - estimate to the absolute error = ', &
abserr%value
Write (nout,99998) 'derivative of results w.r.t ruser(1) = ', dr
Write (nout,*)
If (abserr>max(epsabs,(epsrel)*abs(result))) Then
Write (nout,*) &
'Warning - requested accuracy may not have been achieved'
End If
! Remove computational data object and tape
ifail = 0
Call x10ab_a1w_f(ad_handle,ifail)
Call nagad_a1w_ir_remove
99999 Format (1X,A,F10.4)
99998 Format (1X,A,E9.2)
99997 Format (1X,A,F9.5)
End Program d01bd_a1w_fe