PROGRAM f04ahfe

!      F04AHF Example Program Text

!      Mark 23 Release. NAG Copyright 2011.

!      .. Use Statements ..
       USE nag_library, ONLY : f03aff, f04ahf, nag_wp, x02ajf
!      .. Implicit None Statement ..
       IMPLICIT NONE
!      .. Parameters ..
       INTEGER, PARAMETER              :: nin = 5, nout = 6
!      .. Local Scalars ..
       REAL (KIND=nag_wp)              :: d1, eps
       INTEGER                         :: i, id, ifail, ir, k, lda, ldaa, ldb, &
                                          ldbb, ldx, n
!      .. Local Arrays ..
       REAL (KIND=nag_wp), ALLOCATABLE :: a(:,:), aa(:,:), b(:,:), bb(:,:),    &
                                          p(:), x(:,:)
!      .. Executable Statements ..
       WRITE (nout,*) 'F04AHF Example Program Results'
       WRITE (nout,*)
!      Skip heading in data file
       READ (nin,*)
       READ (nin,*) n
       ir = 1
       lda = n
       ldaa = n
       ldb = n
       ldbb = n
       ldx = n
       ALLOCATE (a(lda,n),aa(ldaa,n),b(ldb,ir),bb(ldbb,ir),p(n),x(ldx,ir))
       READ (nin,*) (aa(i,1:n),i=1,n)
       a(1:n,1:n) = aa(1:n,1:n)

!      ifail: behaviour on error exit
!             =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
       ifail = 0
!      Crout decomposition
       CALL f03aff(n,eps,aa,ldaa,d1,id,p,ifail)

       READ (nin,*) (b(i,1:ir),i=1,n)
       eps = x02ajf()

       ifail = 0
!      Accurate solution of linear equations
       CALL f04ahf(n,ir,a,lda,aa,ldaa,p,b,ldb,eps,x,ldx,bb,ldbb,k,ifail)

       WRITE (nout,*) ' Solution'
       DO i = 1, n
          WRITE (nout,99999) x(i,1:ir)
       END DO

99999  FORMAT (1X,8F9.4)
    END PROGRAM f04ahfe