Program f11zbfe

!     F11ZBF Example Program Text

!     Mark 28.3 Release. NAG Copyright 2022.

!     .. Use Statements ..
      Use nag_library, Only: f11zbf, nag_wp
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
      Integer                          :: i, ifail, n, nnz
      Character (1)                    :: dup, zer
!     .. Local Arrays ..
      Real (Kind=nag_wp), Allocatable  :: a(:)
      Integer, Allocatable             :: icol(:), irow(:), istr(:), iwork(:)
!     .. Executable Statements ..
      Write (nout,*) 'F11ZBF Example Program Results'
!     Skip heading in data file
      Read (nin,*)

!     Read order of matrix and number of nonzero entries

      Read (nin,*) n
      Read (nin,*) nnz

      Allocate (a(nnz),icol(nnz),irow(nnz),istr(n+1),iwork(n))

!     Read and output the original nonzero elements

      Do i = 1, nnz
        Read (nin,*) a(i), irow(i), icol(i)
      End Do
      Write (nout,*) 'Original elements'
      Write (nout,99997) 'NNZ = ', nnz
      Do i = 1, nnz
        Write (nout,99998) i, a(i), irow(i), icol(i)
      End Do

!     Reorder, sum duplicates and remove zeros

      dup = 'S'
      zer = 'R'

!     ifail: behaviour on error exit
!             =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
      ifail = 0
      Call f11zbf(n,nnz,a,irow,icol,dup,zer,istr,iwork,ifail)

!     Output results

      Write (nout,*) 'Reordered elements'
      Write (nout,99999) 'NNZ = ', nnz
      Do i = 1, nnz
        Write (nout,99998) i, a(i), irow(i), icol(i)
      End Do

99999 Format (1X,A,I4)
99998 Format (1X,I8,E16.4,2I8)
99997 Format (1X,A,I16)
    End Program f11zbfe