PROGRAM f08kjfe

!      F08KJF Example Program Text

!      Mark 23 Release. NAG Copyright 2011.

!      .. Use Statements ..
       USE nag_library, ONLY : ddisna, dgesvj, nag_wp, x02ajf, x04caf
!      .. Implicit None Statement ..
       IMPLICIT NONE
!      .. Parameters ..
       INTEGER, PARAMETER              :: nin = 5, nout = 6
!      .. Local Scalars ..
       REAL (KIND=nag_wp)              :: eps, serrbd
       INTEGER                         :: i, ifail, info, j, lda, ldv, lwork,  &
                                          m, n
!      .. Local Arrays ..
       REAL (KIND=nag_wp), ALLOCATABLE :: a(:,:), rcondu(:), rcondv(:), s(:),  &
                                          v(:,:), work(:)
!      .. Intrinsic Functions ..
       INTRINSIC                          abs
!      .. Executable Statements ..
       WRITE (nout,*) 'F08KJF Example Program Results'
       WRITE (nout,*)
       FLUSH (nout)
!      Skip heading in data file
       READ (nin,*)
       READ (nin,*) m, n
       lda = m
       ldv = n
       lwork = n + m
       ALLOCATE (a(lda,n),rcondu(m),rcondv(m),s(n),v(ldv,n),work(lwork))

!      Read the m by n matrix A from data file

       READ (nin,*) ((a(i,j),j=1,n),i=1,m)

!      Compute the singular values and left and right singular vectors
!      of A (A = U*S*V, m.ge.n)

!      The NAG name equivalent of dgesvj is f08kjf
       CALL dgesvj('G','U','V',m,n,a,lda,s,0,v,ldv,work,lwork,info)

       IF (info==0) THEN

!         Compute the approximate error bound for the computed singular values 
!         using the 2-norm, s(1) = norm(A), and machine precision, eps.
          eps = x02ajf()
          serrbd = eps*s(1)

!         Print solution
          WRITE (nout,*) 'Singular values'
          WRITE (nout,99999) (s(j),j=1,n)

          IF (abs(work(1)-1.0_nag_wp)>eps) THEN
             WRITE (nout,99996) 'Values need scaling by factor = ', work(1)
          END IF
          FLUSH (nout)

!         ifail: behaviour on error exit
!                =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
          ifail = 0
          CALL x04caf('General',' ',m,n,a,lda,'Left singular vectors',ifail)

          WRITE (nout,*)
          FLUSH (nout)

          ifail = 0
          CALL x04caf('General',' ',n,n,v,ldv,'Right singular vectors',ifail)


!         Call DDISNA (F08FLF) to estimate reciprocal condition
!         numbers for the singular vectors
          CALL ddisna('Left',m,n,s,rcondu,info)
          CALL ddisna('Right',m,n,s,rcondv,info)

!         Print the approximate error bounds for the singular values
!         and vectors
          WRITE (nout,'(/1X,A)') 'Error estimate for the singular values'
          WRITE (nout,99998) serrbd
          WRITE (nout,'(/1X,A)') 'Error estimates for left singular vectors'
          WRITE (nout,99998) (serrbd/rcondu(i),i=1,n)
          WRITE (nout,'(/1X,A)') 'Error estimates for right singular vectors'
          WRITE (nout,99998) (serrbd/rcondv(i),i=1,n)
       ELSE
          WRITE (nout,99997) 'Failure in DGESVJ. INFO =', info
       END IF


99999  FORMAT (3X,(8F8.4))
99998  FORMAT (4X,1P,6E11.1)
99997  FORMAT (1X,A,I4)
99996  FORMAT (/1X,A,1P,E13.5)
    END PROGRAM f08kjfe