NAG Library Manual, Mark 29.3
Interfaces:  FL   CL   CPP   AD 

NAG AD Library Introduction
Example description
    Program f07ue_p0w_fe

!     F07UE_P0W_F Example Program Text
!     Mark 29.3 Release. NAG Copyright 2023.

!     .. Use Statements ..
      Use iso_c_binding, Only: c_ptr
      Use nagad_library, Only: f07ue_p0w_f
      Use nag_library, Only: nag_wp, x04caf
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: nin = 5, nout = 6
      Character (1), Parameter         :: diag = 'N', trans = 'N'
!     .. Local Scalars ..
      Type (c_ptr)                     :: ad_handle
      Integer                          :: i, ifail, j, ld, ldb, n, nrhs
      Character (1)                    :: uplo
!     .. Local Arrays ..
      Real (Kind=nag_wp), Allocatable  :: a(:), b(:,:)
!     .. Executable Statements ..
      Write (nout,*) 'F07UE_P0W_F Example Program Results'
!     Skip heading in data file
      Read (nin,*)
      Read (nin,*) n, nrhs
      ld = (n*(n+1))/2
      ldb = n
      Allocate (a(ld),b(ldb,nrhs))

!     Read A and B from data file
      a = 0.0_nag_wp
      Read (nin,*) uplo
      If (uplo=='U') Then
        Read (nin,*)((a(i+j*(j+1)/2),j=1,i),i=1,n)
      Else If (uplo=='L') Then
        Read (nin,*)((a(i+(2*n-j)*(j-1)/2),j=1,i),i=1,n)
      End If
      Read (nin,*)(b(i,1:nrhs),i=1,n)

!     Compute solution
      Call f07ue_p0w_f(ad_handle,uplo,trans,diag,n,nrhs,a,b,ldb,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,ldb,'Solution(s)',ifail)

    End Program f07ue_p0w_fe