/* nag_matop_real_gen_matrix_log (f01ejc) Example Program.
 *
 * Copyright 2011, Numerical Algorithms Group.
 *
 * Mark 23, 2011.
 */

#include <math.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagf01.h>
#include <nagx02.h>
#include <nagx04.h>

int main(void)
{

  /* Scalars */
  Integer       exit_status = 0;
  Integer       i, j, n, pda;
  double        imnorm;

  /* Arrays */
  double        *a = 0;


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

  INIT_FAIL(fail);

#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

  /* Output preamble */
  printf("nag_matop_real_gen_matrix_log (f01ejc) ");
  printf("Example Program Results\n\n");

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

  /* Read in the problem size */
  scanf("%ld%*[^\n]", &n);

  pda = n;

  if (!(a = NAG_ALLOC(pda*n, double))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

  /* Read in the matrix a from data file */
  for (i = 1; i <= n; i++)
    for (j = 1; j <= n; j++) scanf("%lf", &A(i, j));
  scanf("%*[^\n]");

  /* Find log(A) using
   * nag_matop_real_gen_matrix_log (f01ejc)
   * Real matrix logarithm
   */
  nag_matop_real_gen_matrix_log(order, n, a, pda, &imnorm, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_matop_real_gen_matrix_log (f01ejc)\n%s\n",
	     fail.message);
      exit_status = 1;
      goto END;
    }
  if (fabs(imnorm) > pow(nag_machine_precision,0.8)) {
    printf("\nWARNING: the error estimate returned in imnorm is larger than"
	   " expected;\n");
    printf("         the matrix solution printed below is suspect:\n");
    printf("         imnorm = %13.4e.\n\n", imnorm);
  }

  /* Print solution using
   * nag_gen_real_mat_print (x04cac)
   * Print real general matrix (easy-to-use)
   */
  nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n,
			 a, pda, "log(A)", NULL, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_gen_real_mat_print (x04cac)\n%s\n", fail.message);
      exit_status = 2;
      goto END;
    }

 END:
  if (a) NAG_FREE(a);
  return exit_status;
}