Program x04dcfe
! X04DCF Example Program Text
! Mark 29.3 Release. NAG Copyright 2023.
! .. Use Statements ..
Use nag_library, Only: nag_wp, x04dcf, ztrttp
! .. Implicit None Statement ..
Implicit None
! .. Parameters ..
Integer, Parameter :: n = 4, nout = 6
! .. Local Scalars ..
Real (Kind=nag_wp) :: aa
Integer :: i, ifail, info, j, lda
Character (1) :: uplo
! .. Local Arrays ..
Complex (Kind=nag_wp), Allocatable :: a(:,:), ap(:)
! .. Intrinsic Procedures ..
Intrinsic :: cmplx, real
! .. Executable Statements ..
Write (nout,*) 'X04DCF Example Program Results'
Write (nout,*)
Flush (nout)
! Generate a full-format symmetric array of data
lda = n
Allocate (a(lda,n))
Do j = 1, n
Do i = 1, j
aa = real(10*i+j,kind=nag_wp)
a(i,j) = cmplx(aa,-aa,kind=nag_wp)
a(j,i) = a(i,j)
End Do
End Do
! Print order (n-1) lower triangular matrix
! Convert a to packed storage.
Allocate (ap(n*(n+1)/2))
! The lower triangle.
uplo = 'L'
! The NAG name equivalent of ztrttp is f01vbf
Call ztrttp(uplo,n-1,a,lda,ap,info)
If (info/=0) Then
Write (nout,99999) 'Failure in ZTRTTP. INFO =', info
Go To 100
End If
ifail = 0
Call x04dcf('Lower','Unit',n-1,ap,'Example 1:',ifail)
Write (nout,*)
Flush (nout)
! Print order n upper triangular matrix
! Convert the upper triangle of a to packed storage.
uplo = 'U'
! The NAG name equivalent of ztrttp is f01vbf
Call ztrttp(uplo,n,a,lda,ap,info)
If (info/=0) Then
Write (nout,99999) 'Failure in ZTRTTP. INFO =', info
Go To 100
End If
ifail = 0
Call x04dcf('Upper','Non-unit',n,ap,'Example 2:',ifail)
100 Continue
99999 Format (1X,A,I4)
End Program x04dcfe