NAG Library Manual, Mark 30
Interfaces:  FL   CL   CPP   AD 

NAG AD Library Introduction
Example description
    Program f07ae_p0w_fe

!     F07AE_P0W_F Example Program Text
!     Mark 30.0 Release. NAG Copyright 2024.

!     .. Use Statements ..
      Use iso_c_binding, Only: c_ptr
      Use nagad_library, Only: f07ad_p0w_f, f07ae_p0w_f
      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, lwork, n, nrhs
!     .. Local Arrays ..
      Real (Kind=nag_wp), Allocatable  :: a(:,:), b(:,:)
      Integer, Allocatable             :: ipiv(:)
!     .. Executable Statements ..
      Write (nout,*) 'F07AE_P0W_F Example Program Results'
!     Skip heading in data file
      Read (nin,*)
      Read (nin,*) n, nrhs

      lwork = 64*n
      Allocate (a(n,n),b(n,nrhs),ipiv(n))

!     Read A from data file
      Read (nin,*)(a(i,1:n),i=1,n)

!     Read B from data file
      Read (nin,*)(b(i,1:nrhs),i=1,n)

!     Factorize A
      ifail = 0
      Call f07ad_p0w_f(ad_handle,n,n,a,n,ipiv,ifail)

!     Solve system
      Call f07ae_p0w_f(ad_handle,'N',n,nrhs,a,n,ipiv,b,n,ifail)

!     ifail: behaviour on error exit
!            =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
      ifail = 0
      Call x04caf('General',' ',n,nrhs,b,n,'Solution',ifail)

    End Program f07ae_p0w_fe