PROGRAM f11jrfe ! F11JRF Example Program Text ! Mark 23 Release. NAG Copyright 2011. ! .. 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 Functions .. 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)) rdiag(irow(i)) = 1.E0_nag_wp/real(a(i)) 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