Program f07aufe
! F07AUF Example Program Text
! Mark 25 Release. NAG Copyright 2014.
! .. 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