/* nag_zgbtrs (f07bsc) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

#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);
  Vprintf("nag_zgbtrs (f07bsc) Example Program Results\n\n");

  /* Skip heading in data file */
  Vscanf("%*[^\n] ");
  Vscanf("%ld%ld%ld%ld%*[^\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)) )
    {
      Vprintf("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)
        Vscanf(" ( %lf , %lf )", &AB(i,j).re, &AB(i,j).im);
    }
  Vscanf("%*[^\n] ");
  /* Read B from data file */
  for (i = 1; i <= n; ++i)
    {
      for (j = 1; j <= nrhs; ++j)
        Vscanf(" ( %lf , %lf )", &B(i,j).re, &B(i,j).im);
    }
  Vscanf("%*[^\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)
    {
      Vprintf("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)
    {
      Vprintf("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)
   */
  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)
    {
      Vprintf("Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }
 END:
  if (ab) NAG_FREE(ab);
  if (b) NAG_FREE(b);
  if (ipiv) NAG_FREE(ipiv);
  return exit_status;
}