PROGRAM f07aufe ! F07AUF Example Program Text ! Mark 23 Release. NAG Copyright 2011. ! .. Use Statements .. USE nag_library, ONLY : nag_wp, x02ajf, zgecon, zgetrf, zlange => f06uaf ! .. Implicit None Statement .. IMPLICIT NONE ! .. Parameters .. INTEGER, PARAMETER :: nin = 5, nout = 6 CHARACTER (1), PARAMETER :: norm = '1' ! .. Local Scalars .. REAL (KIND=nag_wp) :: anorm, rcond INTEGER :: i, info, lda, n ! .. Local Arrays .. COMPLEX (KIND=nag_wp), ALLOCATABLE :: a(:,:), work(:) REAL (KIND=nag_wp), ALLOCATABLE :: rwork(:) INTEGER, ALLOCATABLE :: ipiv(:) ! .. Executable Statements .. WRITE (nout,*) 'F07AUF Example Program Results' ! Skip heading in data file READ (nin,*) READ (nin,*) n lda = n ALLOCATE (a(lda,n),work(2*n),rwork(2*n),ipiv(n)) ! Read A from data file READ (nin,*) (a(i,1:n),i=1,n) ! Compute norm of A ! f06uaf is the NAG name equivalent of the LAPACK auxiliary zlange anorm = zlange(norm,n,n,a,lda,rwork) ! Factorize A ! The NAG name equivalent of zgetrf is f07arf CALL zgetrf(n,n,a,lda,ipiv,info) WRITE (nout,*) IF (info==0) THEN ! Estimate condition number ! The NAG name equivalent of zgecon is f07auf CALL zgecon(norm,n,a,lda,anorm,rcond,work,rwork,info) IF (rcond>=x02ajf()) THEN WRITE (nout,99999) 'Estimate of condition number =', & 1.0_nag_wp/rcond ELSE WRITE (nout,*) 'A is singular to working precision' END IF ELSE WRITE (nout,*) 'The factor U is singular' END IF 99999 FORMAT (1X,A,1P,E10.2) END PROGRAM f07aufe