/* nag_dgbsv (f07bac) Example Program.
 *
 * Copyright 2008 Numerical Algorithms Group.
 *
 * Mark 23, 2011.
 */

#include <stdio.h>
#include <nag.h>
#include <nagx04.h>
#include <nag_stdlib.h>
#include <nagf07.h>

int main(void)
{

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

  /* Arrays */
  double        *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_dgbsv (f07bac) Example Program Results\n\n");

  /* Skip heading in data file */
  scanf("%*[^\n]");

  scanf("%ld%ld%ld%*[^\n] ", &n, &kl, &ku);
  scanf("%ld%*[^\n] ", &nrhs);
  if (n < 0 || kl < 0 || ku < 0 || nrhs < 0)
    {
      printf("One or more of n, kl, ku or nrhs has illegal value\n");
      exit_status = 1;
      goto END;
    }

  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, double)) ||
      !(b = NAG_ALLOC(n*nrhs, double)) ||
      !(ipiv = NAG_ALLOC(n, Integer)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* 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", &AB(i, j));
  scanf("%*[^\n] ");

  for (i = 1; i <= n; ++i)
    for (j = 1; j <= nrhs; ++j) scanf("%lf", &B(i, j));
  scanf("%*[^\n] ");


  /* Solve the equations Ax = b for x using nag_dgbsv (f07bac). */
  nag_dgbsv(order, n, kl, ku, nrhs, ab, pdab, ipiv, b, pdb, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_dgbsv (f07bac).\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("%11.4f%s", B(i, j), j%7 == 0?"\n":" ");
      printf("\n");
    }

  /* Print details of the factorization */
  printf("\n");
  fflush(stdout);
  nag_band_real_mat_print(order, n, n, kl, kl+ku, ab, pdab,
                          "Details of factorization", 0, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_band_real_mat_print (x04cec).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }
  /* Print pivot indices' */
  printf("\nPivot indices\n");
  for (i = 1; i <= n; ++i)
    printf("%11ld%s", ipiv[i-1], i%7 == 0?"\n":" ");
  printf("\n");
 END:
  if (ab) NAG_FREE(ab);
  if (b) NAG_FREE(b);
  if (ipiv) NAG_FREE(ipiv);

  return exit_status;
}

#undef AB
#undef B