/* nag_lapacklin_zgeequ (f07atc) Example Program.
*
* Copyright 2024 Numerical Algorithms Group.
*
* Mark 30.1, 2024.
*/
#include <nag.h>
#include <stdio.h>
int main(void) {
/* Scalars */
double amax, big, colcnd, rowcnd, small;
Integer i, j, m, n, pda;
Integer exit_status = 0;
/* Arrays */
Complex *a = 0;
double *c = 0, *r = 0;
/* Nag Types */
NagError fail;
Nag_OrderType order;
Nag_Boolean scaled = Nag_FALSE;
#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_lapacklin_zgeequ (f07atc) Example Program Results\n\n");
/* Skip heading in data file */
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%*[^\n]", &n);
if (n < 0) {
printf("Invalid n\n");
exit_status = 1;
return exit_status;
}
m = n;
pda = n;
/* Allocate memory */
if (!(a = NAG_ALLOC(m * n, Complex)) || !(c = NAG_ALLOC(n, double)) ||
!(r = NAG_ALLOC(m, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
/* Read the n by n matrix A from data file */
for (i = 1; i <= n; ++i)
for (j = 1; j <= n; ++j)
scanf(" ( %lf , %lf )", &A(i, j).re, &A(i, j).im);
scanf("%*[^\n]");
/* Print the matrix A using nag_file_print_matrix_complex_gen_comp (x04dbc).
*/
fflush(stdout);
nag_file_print_matrix_complex_gen_comp(
order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, a, pda, Nag_BracketForm,
"%11.2e", "Matrix A", 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;
}
printf("\n");
/* Compute row and column scaling factors */
nag_lapacklin_zgeequ(order, n, n, a, pda, r, c, &rowcnd, &colcnd, &amax,
&fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_lapacklin_zgeequ (f07atc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Print rowcnd, colcnd, amax and the scale factors */
printf("rowcnd = %10.1e, colcnd = %10.1e, amax = %10.1e\n\n", rowcnd, colcnd,
amax);
printf("Row scale factors\n");
for (i = 1; i <= n; ++i)
printf("%11.2e%s", r[i - 1], i % 7 == 0 ? "\n" : " ");
printf("\n\nColumn scale factors\n");
for (i = 1; i <= n; ++i)
printf("%11.2e%s", c[i - 1], i % 7 == 0 ? "\n" : " ");
printf("\n\n");
/* Compute values close to underflow and overflow using
* nag_machine_real_safe (x02amc), nag_machine_precision (x02ajc) and
* nag_machine_model_base (x02bhc)
*/
small =
nag_machine_real_safe / (nag_machine_precision * nag_machine_model_base);
big = 1.0 / small;
if (colcnd < 0.1) {
/* column scale A */
scaled = Nag_TRUE;
for (j = 1; j <= n; ++j)
for (i = 1; i <= n; ++i) {
A(i, j).re *= c[j - 1];
A(i, j).im *= c[j - 1];
}
}
if (rowcnd < 0.1 || amax < small || amax > big) {
/* row scale A */
scaled = Nag_TRUE;
for (j = 1; j <= n; ++j)
for (i = 1; i <= n; ++i) {
A(i, j).re *= r[i - 1];
A(i, j).im *= r[i - 1];
}
}
if (scaled) {
/* Print the scaled matrix using nag_file_print_matrix_complex_gen_comp
* (x04dbc) */
fflush(stdout);
nag_file_print_matrix_complex_gen_comp(
order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, a, pda,
Nag_BracketForm, 0, "Scaled matrix", 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(a);
NAG_FREE(c);
NAG_FREE(r);
return exit_status;
}