Program f11jrfe

!     F11JRF Example Program Text

!     Mark 27.3 Release. NAG Copyright 2021.

!     .. Use Statements ..
      Use nag_library, Only: f11jrf, nag_wp
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
      Real (Kind=nag_wp)               :: omega
      Integer                          :: i, ifail, n, nnz
      Character (1)                    :: check
!     .. Local Arrays ..
      Complex (Kind=nag_wp), Allocatable :: a(:), x(:), y(:)
      Real (Kind=nag_wp), Allocatable  :: rdiag(:)
      Integer, Allocatable             :: icol(:), irow(:), iwork(:)
!     .. Intrinsic Procedures ..
      Intrinsic                        :: real
!     .. Executable Statements ..
      Write (nout,*) 'F11JRF Example Program Results'
!     Skip heading in data file
      Read (nin,*)

!     Read algorithmic parameters

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

      Allocate (a(nnz),x(n),y(n),rdiag(n),icol(nnz),irow(nnz),iwork(n+1))
      Read (nin,*) check
      Read (nin,*) omega

!     Read the matrix A

      Do i = 1, nnz
        Read (nin,*) a(i), irow(i), icol(i)
      End Do

!     Read rhs vector y

      Read (nin,*) y(1:n)

!     Fill in the diagonal part

      Do i = 1, nnz
        If (irow(i)==icol(i)) Then
          rdiag(irow(i)) = 1.E0_nag_wp/real(a(i))
        End If
      End Do

!     Solve Mx = b using F11JRF

!     ifail: behaviour on error exit
!             =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
      ifail = 0
      Call f11jrf(n,nnz,a,irow,icol,rdiag,omega,check,y,x,iwork,ifail)

!     Output x

      Write (nout,99999) x(1:n)

99999 Format (1X,'(',E16.4,',',E16.4,')')
    End Program f11jrfe