PROGRAM f11dqfe ! F11DQF Example Program Text ! Mark 23 Release. NAG Copyright 2011. ! .. Use Statements .. USE nag_library, ONLY : f11dnf, f11dqf, nag_wp ! .. Implicit None Statement .. IMPLICIT NONE ! .. Parameters .. INTEGER, PARAMETER :: nin = 5, nout = 6 ! .. Local Scalars .. REAL (KIND=nag_wp) :: dtol, rnorm, tol INTEGER :: i, ifail, itn, la, lfill, liwork, & lwork, m, maxitn, n, nnz, nnzc, npivm CHARACTER (8) :: method CHARACTER (1) :: milu, pstrat ! .. Local Arrays .. COMPLEX (KIND=nag_wp), ALLOCATABLE :: a(:), b(:), work(:), x(:) INTEGER, ALLOCATABLE :: icol(:), idiag(:), ipivp(:), & ipivq(:), irow(:), istr(:), iwork(:) ! .. Intrinsic Functions .. INTRINSIC max ! .. Executable Statements .. WRITE (nout,*) 'F11DQF Example Program Results' WRITE (nout,*) ! Skip heading in data file READ (nin,*) ! Read algorithmic parameters READ (nin,*) n, m READ (nin,*) nnz la = 2*nnz liwork = 7*n + 2 lwork = max(4*n+m*(m+n+5)+121,8*n+120,2*n*(m+3)+m*(m+2)+120,11*n+120) ALLOCATE (a(la),b(n),work(lwork),x(n),icol(la),idiag(n),ipivp(n), & ipivq(n),irow(la),istr(n+1),iwork(liwork)) READ (nin,*) method READ (nin,*) lfill, dtol READ (nin,*) pstrat READ (nin,*) milu READ (nin,*) tol, maxitn ! Read the matrix A DO i = 1, nnz READ (nin,*) a(i), irow(i), icol(i) END DO ! Read rhs vector b and initial approximate solution x READ (nin,*) b(1:n) READ (nin,*) x(1:n) ! Calculate incomplete LU factorization ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 CALL f11dnf(n,nnz,a,la,irow,icol,lfill,dtol,pstrat,milu,ipivp,ipivq, & istr,idiag,nnzc,npivm,iwork,liwork,ifail) ! Solve Ax = b using F11DQF ifail = 0 CALL f11dqf(method,n,nnz,a,la,irow,icol,ipivp,ipivq,istr,idiag,b,m,tol, & maxitn,x,rnorm,itn,work,lwork,ifail) WRITE (nout,99999) itn WRITE (nout,99998) rnorm WRITE (nout,*) ! Output x WRITE (nout,*) ' X' WRITE (nout,99997) x(1:n) 99999 FORMAT (1X,'Converged in',I10,' iterations') 99998 FORMAT (1X,'Final residual norm =',1P,E16.3) 99997 FORMAT (1X,'(',1P,E16.4,',',1P,E16.4,')') END PROGRAM f11dqfe