/* nag_lapacklin_zgttrf (f07crc) 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, n;

  /* Arrays */
  Complex *d = 0, *dl = 0, *du = 0, *du2 = 0;
  Integer *ipiv = 0;

  /* Nag Types */
  NagError fail;

  INIT_FAIL(fail);

  printf("nag_lapacklin_zgttrf (f07crc) 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;
    goto END;
  }

  /* Allocate memory */
  if (!(d = NAG_ALLOC(n, Complex)) || !(dl = NAG_ALLOC(n - 1, Complex)) ||
      !(du = NAG_ALLOC(n - 1, Complex)) || !(du2 = NAG_ALLOC(n - 2, Complex)) ||
      !(ipiv = NAG_ALLOC(n, Integer))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

  /* Read the tridiagonal matrix A 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]");

  /* Factorize the tridiagonal matrix A using nag_lapacklin_zgttrf (f07crc). */
  nag_lapacklin_zgttrf(n, dl, d, du, du2, ipiv, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_lapacklin_zgttrf (f07crc).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  /* Print details of the factorization */
  printf("Details of factorization (U)\n\n");

  printf("%17s%24s%22s\n", "Main diagonal", "First superdiagonal",
         "Second superdiagonal");
  for (i = 0; i < n; ++i) {
    printf("(%8.4f, %8.4f)", d[i].re, d[i].im);
    if (i < n - 1)
      printf(" (%8.4f, %8.4f)", du[i].re, du[i].im);
    if (i < n - 2)
      printf(" (%8.4f, %8.4f)", du2[i].re, du2[i].im);
    printf("\n");
  }

  printf("\n Multipliers\n");
  for (i = 0; i < n - 1; ++i)
    printf("(%8.4f, %8.4f)\n", dl[i].re, dl[i].im);

  printf("\n Vector of interchanges\n");
  for (i = 0; i < n; ++i)
    printf("%7" NAG_IFMT "%s", ipiv[i], i % 5 == 4 ? "\n" : " ");
  printf("\n");
END:
  NAG_FREE(d);
  NAG_FREE(dl);
  NAG_FREE(du);
  NAG_FREE(du2);
  NAG_FREE(ipiv);

  return exit_status;
}