! D01FB_T1W_F Example Program Text
! Mark 30.1 Release. NAG Copyright 2024.
Module d01fb_t1w_fe_mod
! .. Use Statements ..
Use iso_c_binding, Only: c_ptr
Use nagad_library, Only: exp, nagad_t1w_w_rtype, Operator (/), &
Operator (**), Operator (+), Operator (-), &
Operator (*)
Use nag_library, Only: nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Accessibility Statements ..
Private
Public :: fun
! .. Parameters ..
Integer, Parameter, Public :: ndim = 4, nout = 6
Contains
Subroutine fun(ad_handle,ndim,x,ret,iuser,ruser)
! .. Scalar Arguments ..
Type (c_ptr), Intent (Inout) :: ad_handle
Type (nagad_t1w_w_rtype), Intent (Out) :: ret
Integer, Intent (In) :: ndim
! .. Array Arguments ..
Type (nagad_t1w_w_rtype), Intent (Inout) :: ruser(*)
Type (nagad_t1w_w_rtype), Intent (In) :: x(ndim)
Integer, Intent (Inout) :: iuser(*)
! .. Executable Statements ..
ret = (x(1)*x(2)*x(3))**6/(x(4)+2.0E0_nag_wp)**8* &
exp(-2.0_nag_wp*x(2)-0.5_nag_wp*x(3)*x(3))
Return
End Subroutine fun
End Module d01fb_t1w_fe_mod
Program d01fb_t1w_fe
! D01FB_T1W_F Example Main Program
! .. Use Statements ..
Use d01fb_t1w_fe_mod, Only: fun, ndim, nout
Use iso_c_binding, Only: c_ptr
Use nagad_library, Only: d01fb_t1w_f, nagad_t1w_w_rtype, x10aa_t1w_f, &
x10ab_t1w_f, Assignment (=)
Use nag_library, Only: d01tbf, nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Local Scalars ..
Type (c_ptr) :: ad_handle
Type (nagad_t1w_w_rtype) :: ans
Real (Kind=nag_wp) :: a, b
Integer :: i, ifail, j, k, lwa
! .. Local Arrays ..
Type (nagad_t1w_w_rtype), Allocatable :: abscis_t1w(:), weight_t1w(:)
Type (nagad_t1w_w_rtype) :: ruser(1)
Real (Kind=nag_wp), Allocatable :: abscis(:), weight(:)
Integer :: iuser(1), nptvec(ndim)
! .. Intrinsic Procedures ..
Intrinsic :: sum
! .. Executable Statements ..
Write (nout,*) 'D01FB_T1W_F Example Program Results'
nptvec(1:ndim) = (/4,4,4,4/)
lwa = sum(nptvec(1:ndim))
Allocate (abscis(lwa),weight(lwa),abscis_t1w(lwa),weight_t1w(lwa))
j = 1
! Evaluate primal weights and abscisae in each dimension
Do i = 1, 4
ifail = 0
Select Case (i)
Case (1)
a = 1.0E0_nag_wp
b = 2.0E0_nag_wp
Call d01tbf(0,a,b,nptvec(i),weight(j),abscis(j),ifail)
Case (2)
a = 0.0E0_nag_wp
b = 2.0E0_nag_wp
Call d01tbf(-3,a,b,nptvec(i),weight(j),abscis(j),ifail)
Case (3)
a = 0.0E0_nag_wp
b = 0.5E0_nag_wp
Call d01tbf(-4,a,b,nptvec(i),weight(j),abscis(j),ifail)
Case (4)
a = 1.0E0_nag_wp
b = 2.0E0_nag_wp
Call d01tbf(-5,a,b,nptvec(i),weight(j),abscis(j),ifail)
End Select
j = j + nptvec(i)
End Do
! Create AD configuration data object
ifail = 0
Call x10aa_t1w_f(ad_handle,ifail)
weight_t1w(1:lwa) = weight(1:lwa)
abscis_t1w(1:lwa) = abscis(1:lwa)
! Get primal solution
ifail = 0
Call d01fb_t1w_f(ad_handle,ndim,nptvec,lwa,weight_t1w,abscis_t1w,fun, &
ans,iuser,ruser,ifail)
Write (nout,*)
Write (nout,99999) ' Solution, x =', ans%value
Write (nout,*)
Write (nout,*) ' Derivatives calculated: First order tangents'
Write (nout,*) ' Computational mode : algorithmic'
Write (nout,*) ' Derivatives:'
Write (nout,*) ' dim j da/dweight da/dabscis'
j = 0
Do i = 1, 4
Do k = 1, nptvec(i)
j = j + 1
! Call the AD routine for derivative s.r.t. weight and abscissa
weight_t1w(j)%tangent = 1.0_nag_wp
ifail = 0
Call d01fb_t1w_f(ad_handle,ndim,nptvec,lwa,weight_t1w,abscis_t1w, &
fun,ans,iuser,ruser,ifail)
weight(j) = ans%tangent
weight_t1w(j)%tangent = 0.0_nag_wp
abscis_t1w(j)%tangent = 1.0_nag_wp
ifail = 0
Call d01fb_t1w_f(ad_handle,ndim,nptvec,lwa,weight_t1w,abscis_t1w, &
fun,ans,iuser,ruser,ifail)
abscis(j) = ans%tangent
abscis_t1w(j)%tangent = 0.0_nag_wp
If (k==1) Then
Write (nout,99998) i, 1, weight(j), abscis(j)
Else
Write (nout,99997) k, weight(j), abscis(j)
End If
End Do
End Do
99999 Format (1X,A,1X,F12.5)
99998 Format (1X,I3,1X,I3,1X,E12.5,1X,E12.5)
99997 Format (6X,I2,1X,E12.5,1X,E12.5)
! Remove computational data object
ifail = 0
Call x10ab_t1w_f(ad_handle,ifail)
End Program d01fb_t1w_fe