Program f07ugfe
! F07UGF Example Program Text
! Mark 30.3 Release. nAG Copyright 2024.
! .. Use Statements ..
Use nag_library, Only: dtpcon, nag_wp, x02ajf
! .. 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, j, n
Character (1) :: uplo
! .. Local Arrays ..
Real (Kind=nag_wp), Allocatable :: ap(:), work(:)
Integer, Allocatable :: iwork(:)
! .. Executable Statements ..
Write (nout,*) 'F07UGF Example Program Results'
! Skip heading in data file
Read (nin,*)
Read (nin,*) n
Allocate (ap(n*(n+1)/2),work(3*n),iwork(n))
! Read A from data file
Read (nin,*) uplo
If (uplo=='U') Then
Read (nin,*)((ap(i+j*(j-1)/2),j=i,n),i=1,n)
Else If (uplo=='L') Then
Read (nin,*)((ap(i+(2*n-j)*(j-1)/2),j=1,i),i=1,n)
End If
! Estimate condition number
! The NAG name equivalent of dtpcon is f07ugf
Call dtpcon(norm,uplo,diag,n,ap,rcond,work,iwork,info)
Write (nout,*)
If (rcond>=x02ajf()) Then
Write (nout,99999) 'Estimate of condition number =', &
1.0E0_nag_wp/rcond
Else
Write (nout,*) 'A is singular to working precision'
End If
99999 Format (1X,A,1P,E10.2)
End Program f07ugfe