Program f11xafe
! F11XAF Example Program Text
! Mark 25 Release. NAG Copyright 2014.
! .. Use Statements ..
Use nag_library, Only: f11xaf, nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Parameters ..
Integer, Parameter :: nin = 5, nout = 6
! .. Local Scalars ..
Integer :: i, ifail, n, nnz
Character (1) :: check, trans
! .. Local Arrays ..
Real (Kind=nag_wp), Allocatable :: a(:), x(:), y(:)
Integer, Allocatable :: icol(:), irow(:)
! .. Executable Statements ..
Write (nout,*) 'F11XAF Example Program Results'
! Skip heading in data file
Read (nin,*)
! Read order of matrix and number of non-zero entries
Read (nin,*) n
Read (nin,*) nnz
Allocate (a(nnz),x(n),y(n),icol(nnz),irow(nnz))
! Read the matrix A
Do i = 1, nnz
Read (nin,*) a(i), irow(i), icol(i)
End Do
! Read the vector x
Read (nin,*) x(1:n)
! Calculate matrix-vector product
trans = 'N'
check = 'C'
! ifail: behaviour on error exit
! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
ifail = 0
Call f11xaf(trans,n,nnz,a,irow,icol,check,x,y,ifail)
! Output results
Write (nout,*)
Write (nout,*) ' Matrix-vector product'
Write (nout,'(E16.4)') y(1:n)
! Calculate transposed matrix-vector product
trans = 'T'
check = 'N'
ifail = 0
Call f11xaf(trans,n,nnz,a,irow,icol,check,x,y,ifail)
! Output results
Write (nout,*)
Write (nout,*) ' Transposed matrix-vector product'
Write (nout,'(E16.4)') y(1:n)
End Program f11xafe