Program d01ga_a1w_fe
! D01GA_A1W_F Example Program Text
! Mark 30.1 Release. NAG Copyright 2024.
! .. Use Statements ..
Use iso_c_binding, Only: c_ptr
Use nagad_library, Only: d01ga_a1w_f, nagad_a1w_get_derivative, &
nagad_a1w_inc_derivative, &
nagad_a1w_ir_create => x10za_a1w_f, &
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, Assignment (=), &
Operator (/), Operator (+), Operator (*)
Use nag_library, Only: nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Parameters ..
Integer, Parameter :: nin = 5, nout = 6
! .. Local Scalars ..
Type (nagad_a1w_w_rtype) :: a, ans, er
Type (c_ptr) :: ad_handle
Real (Kind=nag_wp) :: ar, da, xr
Integer :: i, ifail, n
! .. Local Arrays ..
Type (nagad_a1w_w_rtype), Allocatable :: x(:), y(:)
! .. Intrinsic Procedures ..
Intrinsic :: real
! .. Executable Statements ..
Write (nout,*) 'D01GA_A1W_F Example Program Results'
! Skip heading in data file
Read (nin,*)
Read (nin,*) n
Read (nin,*) ar
a = ar
Allocate (x(n),y(n))
! Create AD tape
Call nagad_a1w_ir_create
! 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(a)
Do i = 1, n
xr = real(i-1,kind=nag_wp)/real(n-1,kind=nag_wp)
x(i) = xr
y(i) = 4.0_nag_wp/(1.0_nag_wp+a*a*xr*xr)
End Do
! Call the AD routine
ifail = 0
Call d01ga_a1w_f(ad_handle,x,y,n,ans,er,ifail)
Write (nout,*)
Write (nout,99999) ' Solution, ans =', ans%value
Write (nout,*)
Call nagad_a1w_inc_derivative(ans,1.0E0_nag_wp)
Call nagad_a1w_ir_interpret_adjoint_sparse(ifail)
Write (nout,*) ' Derivatives calculated: First order adjoints'
Write (nout,*) ' Computational mode : algorithmic'
! Get derivatives
da = nagad_a1w_get_derivative(a)
Write (nout,*) ' Derivatives of solution w.r.t a:'
Write (nout,*)
Write (nout,99998) ' d(ans)/da = ', da
99999 Format (1X,A,1X,F12.5)
99998 Format (1X,A,E13.5)
! Remove computational data object and tape
ifail = 0
Call x10ab_a1w_f(ad_handle,ifail)
Call nagad_a1w_ir_remove
End Program d01ga_a1w_fe