/* nag_lapacklin_zgtsv (f07cnc) Example Program.
*
* Copyright 2024 Numerical Algorithms Group.
*
* Mark 30.3, 2024.
*/
#include <nag.h>
#include <stdio.h>
int main(void) {
/* Scalars */
Integer exit_status = 0, i, j, n, nrhs, pdb;
/* Arrays */
Complex *b = 0, *d = 0, *dl = 0, *du = 0;
/* Nag Types */
NagError fail;
Nag_OrderType order;
#ifdef NAG_COLUMN_MAJOR
#define B(I, J) b[(J - 1) * pdb + I - 1]
order = Nag_ColMajor;
#else
#define B(I, J) b[(I - 1) * pdb + J - 1]
order = Nag_RowMajor;
#endif
INIT_FAIL(fail);
printf("nag_lapacklin_zgtsv (f07cnc) 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;
}
/* Allocate memory */
if (!(b = NAG_ALLOC(n * nrhs, Complex)) || !(d = NAG_ALLOC(n, Complex)) ||
!(dl = NAG_ALLOC(n - 1, Complex)) || !(du = NAG_ALLOC(n - 1, Complex))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
#ifdef NAG_COLUMN_MAJOR
pdb = n;
#else
pdb = nrhs;
#endif
/* Read the tridiagonal matrix A and the right hand side B from data file */
for (i = 0; i < n - 1; ++i)
scanf(" ( %lf , %lf )", &du[i].re, &du[i].im);
scanf("%*[^\n]");
for (i = 0; i < n; ++i)
scanf(" ( %lf , %lf )", &d[i].re, &d[i].im);
scanf("%*[^\n]");
for (i = 0; i < n - 1; ++i)
scanf(" ( %lf , %lf )", &dl[i].re, &dl[i].im);
scanf("%*[^\n]");
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 using nag_lapacklin_zgtsv (f07cnc). */
nag_lapacklin_zgtsv(order, n, nrhs, dl, d, du, b, pdb, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_lapacklin_zgtsv (f07cnc).\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("(%8.4f, %8.4f)%s", B(i, j).re, B(i, j).im,
j % 4 == 0 ? "\n" : " ");
printf("\n");
}
END:
NAG_FREE(b);
NAG_FREE(d);
NAG_FREE(dl);
NAG_FREE(du);
return exit_status;
}