/* nag_lapacklin_zgbsv (f07bnc) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.0, 2024.
 */

#include <nag.h>
#include <stdio.h>

int main(void) {

  /* Scalars */
  Integer exit_status = 0, i, j, kl, ku, n, nrhs, pdab, pdb;

  /* Arrays */
  Complex *ab = 0, *b = 0;
  Integer *ipiv = 0;

  /* Nag Types */
  NagError fail;
  Nag_OrderType order;

#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_lapacklin_zgbsv (f07bnc) Example Program Results\n\n");

  /* Skip heading in data file */
  scanf("%*[^\n]");
  scanf("%" NAG_IFMT "%" NAG_IFMT "%" NAG_IFMT "%*[^\n]", &n, &kl, &ku);
  scanf("%" NAG_IFMT "%*[^\n]", &nrhs);
  if (n < 0 || kl < 0 || ku < 0 || nrhs < 0) {
    printf("Invalid n, kl, ku or nrhs\n");
    exit_status = 1;
    goto END;
  }
  /* Allocate memory */
  if (!(ab = NAG_ALLOC((2 * kl + ku + 1) * n, Complex)) ||
      !(b = NAG_ALLOC(n * nrhs, Complex)) || !(ipiv = NAG_ALLOC(n, Integer))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

  pdab = 2 * kl + ku + 1;
#ifdef NAG_COLUMN_MAJOR
  pdb = n;
#else
  pdb = nrhs;
#endif
  /* Read the band matrix A and the right hand side b 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]");
  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_zgbsv (f07bnc). */
  nag_lapacklin_zgbsv(order, n, kl, ku, nrhs, ab, pdab, ipiv, b, pdb, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_lapacklin_zgbsv (f07bnc).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }
  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 == 0 ? "\n" : " ");
    printf("\n");
  }
  printf("\n");

  /* Print details of the factorization using
   * nag_file_print_matrix_complex_band_comp (x04dfc).
   */
  fflush(stdout);
  nag_file_print_matrix_complex_band_comp(
      order, n, n, kl, kl + ku, ab, pdab, Nag_BracketForm, "%7.4f",
      "Details of factorization", Nag_IntegerLabels, 0, Nag_IntegerLabels, 0,
      80, 0, 0, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_file_print_matrix_complex_band_comp (x04dfc).\n%s\n",
           fail.message);
    exit_status = 1;
    goto END;
  }
  /* Print pivot indices' */
  printf("\nPivot indices\n");
  for (i = 1; i <= n; ++i)
    printf("%11" NAG_IFMT "", ipiv[i - 1]);
  printf("\n");
END:
  NAG_FREE(ab);
  NAG_FREE(b);
  NAG_FREE(ipiv);
  return exit_status;
}

#undef AB
#undef B