Program zsysvx_example ! ZSYSVX Example Program Text ! Copyright 2017, Numerical Algorithms Group Ltd. http://www.nag.com ! .. Use Statements .. Use lapack_example_aux, Only: nagf_file_print_matrix_complex_gen_comp Use lapack_interfaces, Only: zsysvx Use lapack_precision, Only: dp ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nb = 64, nin = 5, nout = 6 ! .. Local Scalars .. Real (Kind=dp) :: rcond Integer :: i, ifail, info, lda, ldaf, ldb, ldx, lwork, n, nrhs ! .. Local Arrays .. Complex (Kind=dp), Allocatable :: a(:, :), af(:, :), b(:, :), work(:), & x(:, :) Real (Kind=dp), Allocatable :: berr(:), ferr(:), rwork(:) Integer, Allocatable :: ipiv(:) Character (1) :: clabs(1), rlabs(1) ! .. Executable Statements .. Write (nout, *) 'ZSYSVX Example Program Results' Write (nout, *) Flush (nout) ! Skip heading in data file Read (nin, *) Read (nin, *) n, nrhs lda = n ldaf = n ldb = n ldx = n lwork = nb*n Allocate (a(lda,n), af(ldaf,n), b(ldb,nrhs), work(lwork), x(ldx,nrhs), & berr(nrhs), ferr(nrhs), rwork(n), ipiv(n)) ! Read the upper triangular part of A from data file Read (nin, *)(a(i,i:n), i=1, n) ! Read B from data file Read (nin, *)(b(i,1:nrhs), i=1, n) ! Solve the equations AX = B for X Call zsysvx('Not factored', 'Upper', n, nrhs, a, lda, af, ldaf, ipiv, b, & ldb, x, ldx, rcond, ferr, berr, work, lwork, rwork, info) If ((info==0) .Or. (info==n+1)) Then ! Print solution, error bounds and condition number ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 Call nagf_file_print_matrix_complex_gen_comp('General', ' ', n, nrhs, & x, ldx, 'Bracketed', 'F7.4', 'Solution(s)', 'Integer', rlabs, & 'Integer', clabs, 80, 0, ifail) Write (nout, *) Write (nout, *) 'Backward errors (machine-dependent)' Write (nout, 100) berr(1:nrhs) Write (nout, *) Write (nout, *) 'Estimated forward error bounds (machine-dependent)' Write (nout, 100) ferr(1:nrhs) Write (nout, *) Write (nout, *) 'Estimate of reciprocal condition number' Write (nout, 100) rcond Write (nout, *) If (info==n+1) Then Write (nout, *) Write (nout, *) 'The matrix A is singular to working precision' End If Else Write (nout, 110) 'The diagonal block ', info, ' of D is zero' End If 100 Format ((3X,1P,7E11.1)) 110 Format (1X, A, I3, A) End Program