NAG Library Manual, Mark 28.5
```    Program f07mvfe

!     F07MVF Example Program Text

!     Mark 28.5 Release. NAG Copyright 2022.

!     .. Use Statements ..
Use nag_library, Only: f06tff, nag_wp, x04dbf, zherfs, zhetrf, zhetrs
!     .. Implicit None Statement ..
Implicit None
!     .. Parameters ..
Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
Integer                          :: i, ifail, info, lda, ldaf, ldb, ldx, &
lwork, n, nrhs
Character (1)                    :: uplo
!     .. Local Arrays ..
Complex (Kind=nag_wp), Allocatable :: a(:,:), af(:,:), b(:,:), work(:),  &
x(:,:)
Real (Kind=nag_wp), Allocatable  :: berr(:), ferr(:), rwork(:)
Integer, Allocatable             :: ipiv(:)
Character (1)                    :: clabs(1), rlabs(1)
!     .. Executable Statements ..
Write (nout,*) 'F07MVF Example Program Results'
!     Skip heading in data file
lda = n
ldaf = n
ldb = n
ldx = n
lwork = 64*n
Allocate (a(lda,n),af(ldaf,n),b(ldb,nrhs),work(lwork),x(ldx,n),          &
berr(nrhs),ferr(nrhs),rwork(n),ipiv(n))

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

If (uplo=='U') Then
Else If (uplo=='L') Then
End If

Call f06tff(uplo,n,n,a,lda,af,ldaf)
x(1:n,1:nrhs) = b(1:n,1:nrhs)

!     Factorize A in the array AF
!     The NAG name equivalent of zhetrf is f07mrf
Call zhetrf(uplo,n,af,ldaf,ipiv,work,lwork,info)

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

!       Compute solution in the array X
!       The NAG name equivalent of zhetrs is f07msf
Call zhetrs(uplo,n,nrhs,af,ldaf,ipiv,x,ldx,info)

!       Improve solution, and compute backward errors and
!       estimated bounds on the forward errors

!       The NAG name equivalent of zherfs is f07mvf
Call zherfs(uplo,n,nrhs,a,lda,af,ldaf,ipiv,b,ldb,x,ldx,ferr,berr,work, &
rwork,info)

!       Print solution

!       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)
Else
Write (nout,*) 'The factor D is singular'
End If

99999 Format ((5X,1P,4(E11.1,7X)))
End Program f07mvfe
```