Program f11mhfe ! F11MHF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: f11mdf, f11mef, f11mff, f11mhf, nag_wp, x04caf, & x04cbf ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Real (Kind=nag_wp), Parameter :: one = 1.E0_nag_wp Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Real (Kind=nag_wp) :: flop, thresh Integer :: i, ifail, j, ldb, ldx, n, nnz, nnzl, & nnzu, nrhs, nzlmx, nzlumx, nzumx Character (1) :: spec, trans ! .. Local Arrays .. Real (Kind=nag_wp), Allocatable :: a(:), b(:,:), berr(:), ferr(:), & lval(:), uval(:), x(:,:) Integer, Allocatable :: icolzp(:), il(:), iprm(:), & irowix(:), iu(:) Character (1) :: clabs(1), rlabs(1) ! .. Executable Statements .. Write (nout,*) 'F11MHF Example Program Results' Flush (nout) ! Skip heading in data file Read (nin,*) ! Read order of matrix and number of right hand sides Read (nin,*) n, nrhs ldb = n ldx = n Allocate (b(ldb,nrhs),berr(nrhs),ferr(nrhs),x(ldx,nrhs),icolzp(n+1), & iprm(7*n)) ! Read the matrix A Read (nin,*) icolzp(1:n+1) nnz = icolzp(n+1) - 1 Allocate (a(nnz),lval(8*nnz),uval(8*nnz),il(7*n+8*nnz+4),irowix(nnz), & iu(2*n+8*nnz+1)) Do i = 1, nnz Read (nin,*) a(i), irowix(i) End Do ! Read the right hand sides Do j = 1, nrhs Read (nin,*) x(1:n,j) b(1:n,j) = x(1:n,j) End Do ! Calculate COLAMD permutation spec = 'M' ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 Call f11mdf(spec,n,icolzp,irowix,iprm,ifail) ! Factorise thresh = one ifail = 0 nzlmx = 8*nnz nzlumx = 8*nnz nzumx = 8*nnz Call f11mef(n,irowix,a,iprm,thresh,nzlmx,nzlumx,nzumx,il,lval,iu,uval, & nnzl,nnzu,flop,ifail) ! Compute solution in array X trans = 'N' ifail = 0 Call f11mff(trans,n,iprm,il,lval,iu,uval,nrhs,x,ldx,ifail) ! Improve solution, and compute backward errors and estimated ! bounds on the forward errors Call f11mhf(trans,n,icolzp,irowix,a,iprm,il,lval,iu,uval,nrhs,b,ldb,x, & ldx,ferr,berr,ifail) ! Print solution Write (nout,*) Flush (nout) Call x04caf('G',' ',n,nrhs,x,ldx,'Solutions',ifail) Call x04cbf('G','X',nrhs,1,ferr,nrhs,'1PE8.1','Estimated Forward Error', & 'N',rlabs,'N',clabs,80,0,ifail) Call x04cbf('G','X',nrhs,1,berr,nrhs,'1PE8.1','Backward Error','N', & rlabs,'N',clabs,80,0,ifail) End Program f11mhfe