```    Program f07hafe

!     F07HAF Example Program Text

!     Mark 27.1 Release. NAG Copyright 2020.

!     .. Use Statements ..
Use nag_library, Only: dpbsv, nag_wp, x04cef
!     .. Implicit None Statement ..
Implicit None
!     .. Parameters ..
Integer, Parameter               :: nin = 5, nout = 6
Character (1), Parameter         :: uplo = 'U'
!     .. Local Scalars ..
Integer                          :: i, ifail, info, j, kd, ldab, n
!     .. Local Arrays ..
Real (Kind=nag_wp), Allocatable  :: ab(:,:), b(:)
!     .. Intrinsic Procedures ..
Intrinsic                        :: max, min
!     .. Executable Statements ..
Write (nout,*) 'F07HAF Example Program Results'
Write (nout,*)
!     Skip heading in data file
ldab = kd + 1
Allocate (ab(ldab,n),b(n))

!     Read the upper or lower triangular part of the band matrix A
!     from data file

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

!     Read b from data file

!     Solve the equations Ax = b for x
!     The NAG name equivalent of dpbsv is f07haf
Call dpbsv(uplo,n,kd,1,ab,ldab,b,n,info)

If (info==0) Then

!       Print solution

Write (nout,*) 'Solution'
Write (nout,99999) b(1:n)

!       Print details of factorization

Write (nout,*)
Flush (nout)

!       ifail: behaviour on error exit
!              =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
ifail = 0
If (uplo=='U') Then
Call x04cef(n,n,0,kd,ab,ldab,'Cholesky factor U',ifail)
Else If (uplo=='L') Then
Call x04cef(n,n,kd,0,ab,ldab,'Cholesky factor L',ifail)
End If

Else
Write (nout,99998) 'The leading minor of order ', info,                &
' is not positive definite'
End If

99999 Format ((3X,7F11.4))
99998 Format (1X,A,I3,A)
End Program f07hafe
```