NAG Library Manual, Mark 28.5
Program f07vsfe

!     F07VSF Example Program Text

!     Mark 28.5 Release. NAG Copyright 2022.

!     .. Use Statements ..
Use nag_library, Only: nag_wp, x04dbf, ztbtrs
!     .. Implicit None Statement ..
Implicit None
!     .. Parameters ..
Integer, Parameter               :: nin = 5, nout = 6
Character (1), Parameter         :: diag = 'N', trans = 'N'
!     .. Local Scalars ..
Integer                          :: i, ifail, info, j, kd, ldab, ldb, n, &
nrhs
Character (1)                    :: uplo
!     .. Local Arrays ..
Complex (Kind=nag_wp), Allocatable :: ab(:,:), b(:,:)
Character (1)                    :: clabs(1), rlabs(1)
!     .. Intrinsic Procedures ..
Intrinsic                        :: max, min
!     .. Executable Statements ..
Write (nout,*) 'F07VSF Example Program Results'
!     Skip heading in data file
ldab = kd + 1
ldb = n
Allocate (ab(ldab,n),b(ldb,nrhs))

!     Read A and B from data file

If (uplo=='U') Then
Do i = 1, n
End Do
Else If (uplo=='L') Then
Do i = 1, n
End Do
End If

!     Compute solution
!     The NAG name equivalent of ztbtrs is f07vsf
Call ztbtrs(uplo,trans,diag,n,kd,nrhs,ab,ldab,b,ldb,info)

!     Print solution

Write (nout,*)
Flush (nout)
If (info==0) Then

!       ifail: behaviour on error exit
!              =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
ifail = 0
Call x04dbf('General',' ',n,nrhs,b,ldb,'Bracketed','F7.4',             &
'Solution(s)','Integer',rlabs,'Integer',clabs,80,0,ifail)

Else
Write (nout,*) 'A is singular'
End If

End Program f07vsfe