NAG Library Manual, Mark 28.7
```    Program f08lefe

!     F08LEF Example Program Text

!     Mark 28.7 Release. NAG Copyright 2022.

!     .. Use Statements ..
Use nag_library, Only: dgbbrd, nag_wp
!     .. Implicit None Statement ..
Implicit None
!     .. Parameters ..
Integer, Parameter               :: nin = 5, nout = 6
Character (1), Parameter         :: vect = 'B'
!     .. Local Scalars ..
Integer                          :: i, info, j, kl, ku, ldab, ldb, ldc,  &
ldpt, ldq, m, n, ncc
!     .. Local Arrays ..
Real (Kind=nag_wp), Allocatable  :: ab(:,:), b(:,:), c(:,:), d(:), e(:), &
pt(:,:), q(:,:), work(:)
!     .. Intrinsic Procedures ..
Intrinsic                        :: abs, max, min
!     .. Executable Statements ..
Write (nout,*) 'F08LEF Example Program Results'
!     Skip heading in data file
Read (nin,*) m, n, kl, ku, ncc
ldab = kl + ku + 1
ldb = m
ldc = m
ldpt = n
ldq = m
Allocate (ab(ldab,n),b(ldb,n),c(m,ncc),d(n),e(n-1),pt(ldpt,n),q(ldq,m),  &
work(2*m+2*n))

!     Read A from data file

!     Reduce A to upper bidiagonal form
!     The NAG name equivalent of dgbbrd is f08lef
Call dgbbrd(vect,m,n,ncc,kl,ku,ab,ldab,d,e,q,ldq,pt,ldpt,c,ldc,work,     &
info)

!     Print the absolute values of bidiagonal vectors d and e.
!     Any of these can differ by a sign change by combinations of sign
!     changes in columns of Q and P (rows of PT).
Write (nout,*)
Write (nout,*) 'Diagonal D:'
Write (nout,99999) abs(d(1:n))
Write (nout,*)
Write (nout,*) 'Off-diagonal E:'
Write (nout,99999) abs(e(1:n-1))
99999 Format (1X,4(3X,F11.4))

End Program f08lefe
```