NAG Library Manual, Mark 28.6
/* nag_lapackeig_zunglq (f08awc) Example Program.
*
* Copyright 2022 Numerical Algorithms Group.
*
* Mark 28.6, 2022.
*/

#include <nag.h>
#include <stdio.h>

int main(void) {
/* Scalars */
Integer i, j, m, n, pda, tau_len;
Integer exit_status = 0;
NagError fail;
Nag_OrderType order;
/* Arrays */
char *title = 0;
Complex *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_zunglq (f08awc) 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
tau_len = m;

/* Allocate memory */
if (!(title = NAG_ALLOC(31, char)) || !(a = NAG_ALLOC(m * n, Complex)) ||
!(tau = NAG_ALLOC(tau_len, Complex))) {
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 , %lf )", &A(i, j).re, &A(i, j).im);
}
scanf("%*[^\n] ");

/* Compute the LQ factorization of A */
/* nag_lapackeig_zgelqf (f08avc).
* LQ factorization of complex general rectangular matrix
*/
nag_lapackeig_zgelqf(order, m, n, a, pda, tau, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_lapackeig_zgelqf (f08avc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

/* Form the leading M rows of Q explicitly */
/* nag_lapackeig_zunglq (f08awc).
* Form all or part of unitary Q from LQ factorization
* determined by nag_lapackeig_zgelqf (f08avc)
*/
nag_lapackeig_zunglq(order, m, n, m, a, pda, tau, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_lapackeig_zunglq (f08awc).\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_complex_gen_comp (x04dbc).
* Print complex general matrix (comprehensive)
*/
fflush(stdout);
nag_file_print_matrix_complex_gen_comp(
order, Nag_GeneralMatrix, Nag_NonUnitDiag, m, n, a, pda, Nag_BracketForm,
"%7.4f", title, Nag_IntegerLabels, 0, Nag_IntegerLabels, 0, 80, 0, 0,
&fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_complex_gen_comp (x04dbc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
END:
NAG_FREE(title);
NAG_FREE(a);
NAG_FREE(tau);

return exit_status;
}