Program dsposv_example ! DSPOSV Example Program Text ! Copyright 2017, Numerical Algorithms Group Ltd. http://www.nag.com ! .. Use Statements .. Use lapack_interfaces, Only: dsposv Use lapack_precision, Only: sp, dp ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Integer :: i, info, iter, lda, ldb, ldx, n, r ! .. Local Arrays .. Real (Kind=dp), Allocatable :: a(:, :), b(:, :), work(:, :), x(:, :) Real (Kind=sp), Allocatable :: swork(:) ! .. Executable Statements .. Write (nout, *) 'DSPOSV Example Program Results' Write (nout, *) ! Skip heading in data file Read (nin, *) Read (nin, *) n, r lda = n ldb = n ldx = n Allocate (a(lda,n), b(n,r), work(n,r), x(ldx,r), swork(n*(n+r))) ! 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:r), i=1, n) ! Solve the equations Ax = b for x Call dsposv('U', n, r, a, lda, b, ldb, x, ldx, work, swork, iter, info) If (info==0) Then ! Print solution Write (nout, *) 'Solution' Write (nout, 100)(x(i,1:r), i=1, n) Else Write (nout, 110) 'The leading minor of order ', info, & ' is not positive definite' End If 100 Format ((3X,7F11.4)) 110 Format ((1X,A,I3,A)) End Program