Program dtptrs_example ! DTPTRS Example Program Text ! Copyright 2017, Numerical Algorithms Group Ltd. http://www.nag.com ! .. Use Statements .. Use lapack_example_aux, Only: nagf_file_print_matrix_real_gen Use lapack_interfaces, Only: dtptrs Use lapack_precision, Only: dp ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 Character (1), Parameter :: diag = 'N', trans = 'N' ! .. Local Scalars .. Integer :: i, ifail, info, j, ldb, n, nrhs Character (1) :: uplo ! .. Local Arrays .. Real (Kind=dp), Allocatable :: ap(:), b(:, :) ! .. Executable Statements .. Write (nout, *) 'DTPTRS Example Program Results' ! Skip heading in data file Read (nin, *) Read (nin, *) n, nrhs ldb = n Allocate (ap(n*(n+1)/2), b(ldb,nrhs)) ! Read A and B from data file Read (nin, *) uplo If (uplo=='U') Then Read (nin, *)((ap(i+j*(j-1)/2),j=i,n), i=1, n) Else If (uplo=='L') Then Read (nin, *)((ap(i+(2*n-j)*(j-1)/2),j=1,i), i=1, n) End If Read (nin, *)(b(i,1:nrhs), i=1, n) ! Compute solution Call dtptrs(uplo, trans, diag, n, nrhs, ap, b, ldb, info) ! Print solution Write (nout, *) Flush (nout) If (info==0) Then ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 Call nagf_file_print_matrix_real_gen('General', ' ', n, nrhs, b, ldb, & 'Solution(s)', ifail) Else Write (nout, *) 'A is singular' End If End Program