/* nag_zgbtrs (f07bsc) Example Program.
*
* NAGPRODCODE Version.
*
* Copyright 2016 Numerical Algorithms Group.
*
* Mark 26, 2016.
*/
#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagf07.h>
#include <nagx04.h>
int main(void)
{
/* Scalars */
Integer i, ipiv_len, j, kl, ku, n, nrhs, pdab, pdb;
Integer exit_status = 0;
NagError fail;
Nag_OrderType order;
/* Arrays */
Complex *ab = 0, *b = 0;
Integer *ipiv = 0;
#ifdef NAG_COLUMN_MAJOR
#define AB(I, J) ab[(J-1)*pdab + kl + ku + I - J]
#define B(I, J) b[(J-1)*pdb + I - 1]
order = Nag_ColMajor;
#else
#define AB(I, J) ab[(I-1)*pdab + kl + J - I]
#define B(I, J) b[(I-1)*pdb + J - 1]
order = Nag_RowMajor;
#endif
INIT_FAIL(fail);
printf("nag_zgbtrs (f07bsc) Example Program Results\n\n");
/* Skip heading in data file */
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%" NAG_IFMT "%" NAG_IFMT "%" NAG_IFMT "%*[^\n] ", &n,
&nrhs, &kl, &ku);
ipiv_len = n;
pdab = 2 * kl + ku + 1;
#ifdef NAG_COLUMN_MAJOR
pdb = n;
#else
pdb = nrhs;
#endif
/* Allocate memory */
if (!(ab = NAG_ALLOC((2 * kl + ku + 1) * n, Complex)) ||
!(b = NAG_ALLOC(nrhs * n, Complex)) ||
!(ipiv = NAG_ALLOC(ipiv_len, Integer)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
/* Read A from data file */
for (i = 1; i <= n; ++i) {
for (j = MAX(i - kl, 1); j <= MIN(i + ku, n); ++j)
scanf(" ( %lf , %lf )", &AB(i, j).re, &AB(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] ");
/* Factorize A */
/* nag_zgbtrf (f07brc).
* LU factorization of complex m by n band matrix
*/
nag_zgbtrf(order, n, n, kl, ku, ab, pdab, ipiv, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_zgbtrf (f07brc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Compute solution */
/* nag_zgbtrs (f07bsc).
* Solution of complex band system of linear equations,
* multiple right-hand sides, matrix already factorized by
* nag_zgbtrf (f07brc)
*/
nag_zgbtrs(order, Nag_NoTrans, n, kl, ku, nrhs, ab, pdab, ipiv,
b, pdb, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_zgbtrs (f07bsc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Print solution */
/* nag_gen_complx_mat_print_comp (x04dbc).
* Print complex general matrix (comprehensive)
*/
fflush(stdout);
nag_gen_complx_mat_print_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n,
nrhs, b, pdb, Nag_BracketForm, "%7.4f",
"Solution(s)", Nag_IntegerLabels,
0, Nag_IntegerLabels, 0, 80, 0, 0, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
END:
NAG_FREE(ab);
NAG_FREE(b);
NAG_FREE(ipiv);
return exit_status;
}