Program f07tufe
! F07TUF Example Program Text
! Mark 25 Release. NAG Copyright 2014.
! .. Use Statements ..
Use nag_library, Only: nag_wp, x02ajf, ztrcon
! .. Implicit None Statement ..
Implicit None
! .. Parameters ..
Integer, Parameter :: nin = 5, nout = 6
Character (1), Parameter :: diag = 'N', norm = '1'
! .. Local Scalars ..
Real (Kind=nag_wp) :: rcond
Integer :: i, info, lda, n
Character (1) :: uplo
! .. Local Arrays ..
Complex (Kind=nag_wp), Allocatable :: a(:,:), work(:)
Real (Kind=nag_wp), Allocatable :: rwork(:)
! .. Executable Statements ..
Write (nout,*) 'F07TUF Example Program Results'
! Skip heading in data file
Read (nin,*)
Read (nin,*) n
lda = n
Allocate (a(lda,n),work(2*n),rwork(n))
! Read A from data file
Read (nin,*) uplo
If (uplo=='U') Then
Read (nin,*)(a(i,i:n),i=1,n)
Else If (uplo=='L') Then
Read (nin,*)(a(i,1:i),i=1,n)
End If
! Estimate condition number
! The NAG name equivalent of ztrcon is f07tuf
Call ztrcon(norm,uplo,diag,n,a,lda,rcond,work,rwork,info)
Write (nout,*)
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
99999 Format (1X,A,1P,E10.2)
End Program f07tufe