Program f11xe_t1w_fe
! F11XE_T1W_F Example Program Text
! Mark 30.0 Release. NAG Copyright 2024.
! .. Use Statements ..
Use iso_c_binding, Only: c_ptr
Use nagad_library, Only: f11xe_t1w_f, nagad_t1w_set_derivative, &
nagad_t1w_w_rtype, x10aa_t1w_f, x10ab_t1w_f, &
Assignment (=)
Use nag_library, Only: nag_wp, x04caf
! .. Implicit None Statement ..
Implicit None
! .. Parameters ..
Integer, Parameter :: nin = 5, nout = 6
! .. Local Scalars ..
Type (c_ptr) :: ad_handle
Integer :: i, ifail, n, nnz
Character (1) :: check
! .. Local Arrays ..
Type (nagad_t1w_w_rtype), Allocatable :: a(:), x(:), y(:)
Real (Kind=nag_wp), Allocatable :: ar(:), dydx(:,:), yr(:)
Integer, Allocatable :: icol(:), irow(:)
! .. Executable Statements ..
Write (nout,*) 'F11XE_T1W_F Example Program Results'
! Skip heading in data file
Read (nin,*)
! Read order of matrix and number of nonzero entries
Read (nin,*) n
Read (nin,*) nnz
Allocate (a(nnz),x(n),y(n),icol(nnz),irow(nnz))
Allocate (ar(nnz),yr(n),dydx(n,n))
! Read the matrix A
Do i = 1, nnz
Read (nin,*) ar(i), irow(i), icol(i)
End Do
a(1:nnz) = ar(1:nnz)
! Read the vector x
Read (nin,*) yr(1:n)
! Create AD configuration data object
ifail = 0
Call x10aa_t1w_f(ad_handle,ifail)
Do i = 1, n
x = yr
Call nagad_t1w_set_derivative(x(i),1.0_nag_wp)
! Calculate matrix-vector product
check = 'C'
ifail = 0
Call f11xe_t1w_f(ad_handle,n,nnz,a,irow,icol,check,x,y,ifail)
x(i)%tangent = 0.0_nag_wp
dydx(1:n,i) = y(1:n)%tangent
End Do
! Output results
Write (nout,*) ' Matrix-vector product'
Write (nout,99999)(y(i)%value,i=1,n)
Write (nout,*)
Write (nout,*) ' Derivatives calculated: First order tangents'
Write (nout,*) ' Computational mode : algorithmic'
Write (nout,*)
Write (nout,*) ' Derivatives of product Y w.r.t. X (A)'
Write (nout,*)
Call x04caf('General',' ',n,n,dydx,n,' dy(i)/dx(j)',ifail)
! Remove computational data object
Call x10ab_t1w_f(ad_handle,ifail)
99999 Format (1X,1P,E16.4)
End Program f11xe_t1w_fe