/* nag_lapacklin_zposv (f07fnc) Example Program.
*
* Copyright 2024 Numerical Algorithms Group.
*
* Mark 30.1, 2024.
*/
#include <nag.h>
#include <stdio.h>
int main(void) {
/* Scalars */
Integer exit_status = 0, i, j, n, nrhs, pda, pdb;
/* Arrays */
Complex *a = 0, *b = 0;
/* Nag Types */
NagError fail;
Nag_OrderType order;
#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[(J - 1) * pda + I - 1]
#define B(I, J) b[(J - 1) * pdb + I - 1]
order = Nag_ColMajor;
#else
#define A(I, J) a[(I - 1) * pda + J - 1]
#define B(I, J) b[(I - 1) * pdb + J - 1]
order = Nag_RowMajor;
#endif
INIT_FAIL(fail);
printf("nag_lapacklin_zposv (f07fnc) Example Program Results\n\n");
/* Skip heading in data file */
scanf("%*[^\n]");
scanf("%" NAG_IFMT "%" NAG_IFMT "%*[^\n]", &n, &nrhs);
if (n < 0 || nrhs < 0) {
printf("Invalid n or nrhs\n");
exit_status = 1;
goto END;
}
pda = n;
#ifdef NAG_COLUMN_MAJOR
pdb = n;
#else
pdb = nrhs;
#endif
/* Allocate memory */
if (!(a = NAG_ALLOC(n * n, Complex)) || !(b = NAG_ALLOC(n * nrhs, Complex))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
/* Read the upper triangular part of A from data file */
for (i = 1; i <= n; ++i)
for (j = i; j <= n; ++j)
scanf(" ( %lf , %lf )", &A(i, j).re, &A(i, j).im);
scanf("%*[^\n]");
/* Read b from data file */
for (i = 1; i <= n; ++i)
for (j = 1; j <= nrhs; ++j)
scanf(" ( %lf , %lf )", &B(i, j).re, &B(i, j).im);
scanf("%*[^\n]");
/* Solve the equations Ax = b for x nag_lapacklin_zposv (f07fnc). */
nag_lapacklin_zposv(order, Nag_Upper, n, nrhs, a, pda, b, pdb, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_lapacklin_zposv (f07fnc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Print solution */
printf("Solution\n");
for (i = 1; i <= n; ++i) {
for (j = 1; j <= nrhs; ++j)
printf("(%7.4f, %7.4f)%s", B(i, j).re, B(i, j).im,
j % 4 == 3 ? "\n" : " ");
printf("\n");
}
/* Print details of factorization using
* nag_file_print_matrix_complex_gen_comp (x04dbc).
*/
printf("\n");
fflush(stdout);
nag_file_print_matrix_complex_gen_comp(
order, Nag_UpperMatrix, Nag_NonUnitDiag, n, n, a, pda, Nag_BracketForm,
"%7.4f", "Cholesky factor U", 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(b);
return exit_status;
}
#undef A
#undef B