NAG Library Manual, Mark 28.4
```    Program f07uvfe

!     F07UVF Example Program Text

!     Mark 28.4 Release. NAG Copyright 2022.

!     .. Use Statements ..
Use nag_library, Only: nag_wp, x04dbf, ztprfs, ztptrs
!     .. 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, ldb, ldx, n, nrhs
Character (1)                    :: uplo
!     .. Local Arrays ..
Complex (Kind=nag_wp), Allocatable :: ap(:), b(:,:), work(:), x(:,:)
Real (Kind=nag_wp), Allocatable  :: berr(:), ferr(:), rwork(:)
Character (1)                    :: clabs(1), rlabs(1)
!     .. Executable Statements ..
Write (nout,*) 'F07UVF Example Program Results'
!     Skip heading in data file
ldb = n
ldx = n
Allocate (ap(n*(n+1)/2),b(ldb,nrhs),work(2*n),x(ldx,n),berr(nrhs),ferr(  &
nrhs),rwork(n))

!     Read A and B from data file, and copy B to X

If (uplo=='U') Then
Else If (uplo=='L') Then
End If
x(1:n,1:nrhs) = b(1:n,1:nrhs)

!     Compute solution in the array X
!     The NAG name equivalent of ztptrs is f07usf
Call ztptrs(uplo,trans,diag,n,nrhs,ap,x,ldx,info)

!     Compute backward errors and estimated bounds on the
!     forward errors

!     The NAG name equivalent of ztprfs is f07uvf
Call ztprfs(uplo,trans,diag,n,nrhs,ap,b,ldb,x,ldx,ferr,berr,work,rwork,  &
info)

!     Print solution

Write (nout,*)
Flush (nout)

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

Write (nout,*)
Write (nout,*) 'Backward errors (machine-dependent)'
Write (nout,99999) berr(1:nrhs)
Write (nout,*) 'Estimated forward error bounds (machine-dependent)'
Write (nout,99999) ferr(1:nrhs)

99999 Format ((5X,1P,4(E11.1,7X)))
End Program f07uvfe
```