/* nag_real_lu_solve_mult_rhs (f04ajc) Example Program.
 *
 * Copyright 1990 Numerical Algorithms Group.
 *
 * Mark 1, 1990.
 * Mark 8 revised, 2004.
 */

#include <nag.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nagf03.h>
#include <nagf04.h>

#define A(I,J) a[(I)*tda + J]
#define B(I,J) b[(I)*tdb + J]
int main(void)
{
  Integer dete, exit_status=0, i, j, n, nrhs, *pivot=0, tda, tdb;
  NagError fail;
  double *a=0, *b=0, detf;

  INIT_FAIL(fail);
  Vprintf("nag_real_lu_solve_mult_rhs (f04ajc) Example Program Results\n");
  /* Skip heading in data file */
  Vscanf("%*[^\n]");
  Vscanf("%ld",&n);
  nrhs = 1;
  if (n>=1)
    {
      if ( !( a = NAG_ALLOC(n*n, double)) ||
           !( b = NAG_ALLOC(n*nrhs, double))  ||
           !( pivot = NAG_ALLOC(n, Integer)) )
        {
          Vprintf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }
      tda = n;
      tdb = nrhs;
    }
  else
    {
      Vprintf("Invalid n.\n");
      exit_status = 1;
      return exit_status;
    }
  for (i=0; i<n; i++)
    for (j=0; j<n; j++)
      Vscanf("%lf",&A(i,j));
  /* Crout decomposition  */
  /* nag_real_lu (f03afc).
   * LU factorization and determinant of real matrix
   */
  nag_real_lu(n, a, tda, pivot, &detf, &dete, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_real_lu (f03afc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  for (i=0; i<n; i++)
    for (j=0; j<nrhs; j++)
      Vscanf("%lf",&B(i,j));
  /*
   * Approximate solution of linear equations
   */
  /* nag_real_lu_solve_mult_rhs (f04ajc).
   * Approximate solution of real simultaneous linear
   * equations (coefficient matrix already factorized by
   * nag_real_lu (f03afc))
   */
  nag_real_lu_solve_mult_rhs(n, nrhs, a, tda, pivot,b, nrhs, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_real_lu_solve_mult_rhs (f04ajc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }
  Vprintf("Solution\n");
  for (i=0; i<n; i++)
    for (j=0; j<nrhs; j++)
      Vprintf("%9.4f\n",B(i,j));
 END:
  if (a) NAG_FREE(a);
  if (b) NAG_FREE(b);
  if (pivot) NAG_FREE(pivot);
  return exit_status;
}