Program ztrcon_example ! ZTRCON Example Program Text ! Copyright 2017, Numerical Algorithms Group Ltd. http://www.nag.com ! .. Use Statements .. Use lapack_interfaces, Only: ztrcon Use lapack_precision, Only: dp ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 Character (1), Parameter :: diag = 'N', norm = '1' ! .. Local Scalars .. Real (Kind=dp) :: rcond Integer :: i, info, lda, n Character (1) :: uplo ! .. Local Arrays .. Complex (Kind=dp), Allocatable :: a(:, :), work(:) Real (Kind=dp), Allocatable :: rwork(:) ! .. Intrinsic Procedures .. Intrinsic :: epsilon ! .. Executable Statements .. Write (nout, *) 'ZTRCON Example Program Results' ! Skip heading in data file Read (nin, *) Read (nin, *) n lda = n Allocate (a(lda,n), work(2*n), rwork(n)) ! Read A from data file Read (nin, *) uplo If (uplo=='U') Then Read (nin, *)(a(i,i:n), i=1, n) Else If (uplo=='L') Then Read (nin, *)(a(i,1:i), i=1, n) End If ! Estimate condition number Call ztrcon(norm, uplo, diag, n, a, lda, rcond, work, rwork, info) Write (nout, *) If (rcond>=epsilon(1.0E0_dp)) Then Write (nout, 100) 'Estimate of condition number =', 1.0_dp/rcond Else Write (nout, *) 'A is singular to working precision' End If 100 Format (1X, A, 1P, E10.2) End Program