Program dorgql_example ! DORGQL 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: dgeqlf, dorgql Use lapack_precision, Only: dp ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nb = 64, nin = 5, nout = 6 ! .. Local Scalars .. Integer :: i, ifail, info, lda, lwork, m, n Character (30) :: title ! .. Local Arrays .. Real (Kind=dp), Allocatable :: a(:, :), tau(:), work(:) ! .. Executable Statements .. Write (nout, *) 'DORGQL Example Program Results' Write (nout, *) ! Skip heading in data file Read (nin, *) Read (nin, *) m, n lda = m lwork = nb*n Allocate (a(lda,n), tau(n), work(lwork)) ! Read A from data file Read (nin, *)(a(i,1:n), i=1, m) ! Compute the QL factorization of A Call dgeqlf(m, n, a, lda, tau, work, lwork, info) ! Form the leading N columns of Q explicitly Call dorgql(m, n, n, a, lda, tau, work, lwork, info) ! Form the heading for NAGF_FILE_PRINT_MATRIX_REAL_GEN Write (title, 100) n Flush (nout) ! Print the leading N columns of Q ! 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', ' ', m, n, a, lda, & title, ifail) 100 Format ('The leading ', I4, ' columns of Q') End Program