/* nag_lapackeig_dorglq (f08ajc) Example Program.
*
* Copyright 2024 Numerical Algorithms Group.
*
* Mark 30.1, 2024.
*/
#include <nag.h>
#include <stdio.h>
int main(void) {
/* Scalars */
Integer i, j, m, n, pda;
Integer exit_status = 0;
NagError fail;
Nag_OrderType order;
/* Arrays */
char *title = 0;
double *a = 0, *tau = 0;
#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[(J - 1) * pda + I - 1]
order = Nag_ColMajor;
#else
#define A(I, J) a[(I - 1) * pda + J - 1]
order = Nag_RowMajor;
#endif
INIT_FAIL(fail);
printf("nag_lapackeig_dorglq (f08ajc) Example Program Results\n\n");
/* Skip heading in data file */
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%" NAG_IFMT "%*[^\n] ", &m, &n);
#ifdef NAG_COLUMN_MAJOR
pda = m;
#else
pda = n;
#endif
/* Allocate memory */
if (!(title = NAG_ALLOC(31, char)) || !(a = NAG_ALLOC(m * n, double)) ||
!(tau = NAG_ALLOC(m, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
/* Read A from data file */
for (i = 1; i <= m; ++i) {
for (j = 1; j <= n; ++j)
scanf("%lf", &A(i, j));
}
scanf("%*[^\n] ");
/* Compute the LQ factorization of A */
/* nag_lapackeig_dgelqf (f08ahc).
* LQ factorization of real general rectangular matrix
*/
nag_lapackeig_dgelqf(order, m, n, a, pda, tau, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_lapackeig_dgelqf (f08ahc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Form the leading M rows of Q explicitly */
/* nag_lapackeig_dorglq (f08ajc).
* Form all or part of orthogonal Q from LQ factorization
* determined by nag_lapackeig_dgelqf (f08ahc)
*/
nag_lapackeig_dorglq(order, m, n, m, a, pda, tau, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_lapackeig_dorglq (f08ajc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Print the leading M rows of Q only */
sprintf(title, "The leading %2" NAG_IFMT " rows of Q\n", m);
/* nag_file_print_matrix_real_gen (x04cac).
* Print real general matrix (easy-to-use)
*/
fflush(stdout);
nag_file_print_matrix_real_gen(order, Nag_GeneralMatrix, Nag_NonUnitDiag, m,
n, a, pda, title, 0, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_real_gen (x04cac).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
END:
NAG_FREE(title);
NAG_FREE(a);
NAG_FREE(tau);
return exit_status;
}