Program f08ytfe
! F08YTF Example Program Text
! Mark 28.7 Release. NAG Copyright 2022.
! .. Use Statements ..
Use nag_library, Only: nag_wp, x04dbf, ztgexc
! .. Implicit None Statement ..
Implicit None
! .. Parameters ..
Integer, Parameter :: nin = 5, nout = 6
Logical, Parameter :: wantq = .False., wantz = .False.
! .. Local Scalars ..
Integer :: i, ifail, ifst, ilst, info, lda, &
ldb, ldq, ldz, n
! .. Local Arrays ..
Complex (Kind=nag_wp), Allocatable :: a(:,:), b(:,:), q(:,:), z(:,:)
Character (1) :: clabs(1), rlabs(1)
! .. Executable Statements ..
Write (nout,*) 'F08YTF Example Program Results'
Write (nout,*)
Flush (nout)
! Skip heading in data file
Read (nin,*)
Read (nin,*) n
ldq = 1
ldz = 1
lda = n
ldb = n
Allocate (a(lda,n),b(ldb,n),q(ldq,1),z(ldz,1))
! Read A and B from data file
Read (nin,*)(a(i,1:n),i=1,n)
Read (nin,*)(b(i,1:n),i=1,n)
! Read the row indices
Read (nin,*) ifst, ilst
! Reorder the A and B
! The NAG name equivalent of ztgexc is f08ytf
Call ztgexc(wantq,wantz,n,a,lda,b,ldb,q,ldq,z,ldz,ifst,ilst,info)
If (info/=0) Then
Write (nout,99999) info, ilst
Write (nout,*)
Flush (nout)
End If
! Print reordered generalized Schur form
! ifail: behaviour on error exit
! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
ifail = 0
Call x04dbf('General',' ',n,n,a,lda,'Bracketed','F7.4', &
'Reordered Schur matrix A','Integer',rlabs,'Integer',clabs,80,0,ifail)
Write (nout,*)
Flush (nout)
ifail = 0
Call x04dbf('General',' ',n,n,b,ldb,'Bracketed','F7.4', &
'Reordered Schur matrix B','Integer',rlabs,'Integer',clabs,80,0,ifail)
99999 Format (' Reordering could not be completed. INFO = ',I3,' ILST = ',I5)
End Program f08ytfe