/* nag_rngs_orthog_matrix (g05qac) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagg05.h>

int main(void)
{
  /* Scalars */
  Integer       i, igen, j, m, n;
  Integer       exit_status = 0;
  Integer       pda;
  NagError      fail;
  Nag_OrderType order;

  /* Arrays */
  double        *a = 0;
  Integer       iseed[4];

#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[(J-1)*pda + I - 1]
  order = Nag_ColMajor;
#else
#define A(I, J) a[(I-1)*pda + J - 1]
  order = Nag_RowMajor;
#endif

  INIT_FAIL(fail);

  printf("nag_rngs_orthog_matrix (g05qac) Example Program Results\n\n");
  m = 4;
  n = 4;
  /* Allocate memory */
  if (!(a = NAG_ALLOC(m * n, double)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
#ifdef NAG_COLUMN_MAJOR
  pda = m;
#else
  pda = n;
#endif

  /* igen identifies the stream. */
  igen = 1;
  /* Initialise the seed to a repeatable sequence */
  iseed[0] = 1762543;
  iseed[1] = 9324783;
  iseed[2] = 423446;
  iseed[3] = 742355;

  /* nag_rngs_init_repeatable (g05kbc).
   * Initialize seeds of a given generator for random number
   * generating functions (that pass seeds explicitly) to give
   * a repeatable sequence
   */
  nag_rngs_init_repeatable(&igen, iseed);

  /* nag_rngs_orthog_matrix (g05qac).
   * Computes a random orthogonal matrix
   */
  nag_rngs_orthog_matrix(order, Nag_RightSide, Nag_InitializeI, m, n, a,
                         pda, igen, iseed, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_rngs_orthog_matrix (g05qac).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }
  for (i = 1; i <= 4; ++i)
    {
      printf("%1s", "");
      for (j = 1; j <= 4; ++j)
        {
          printf("%9.3f", A(i, j));
          printf("%s", j%4 == 0 || j == 4?"\n":" ");
        }
    }
 END:
  if (a) NAG_FREE(a);
  return exit_status;
}