/* nag_matop_real_gen_matrix_cond_sqrt (f01jdc) Example Program.
 *
 * Copyright 2014 Numerical Algorithms Group.
 *
 * Mark 24, 2013.
 */
#include <nag.h>
#include <nag_stdlib.h>
#include <nagf01.h>
#include <nagx04.h>

#define A(I,J) a[J*pda + I]

int main(void)
{
  /* Scalars */
  Integer        exit_status = 0;
  Integer        i, j, n, pda;
  double         alpha, condsa;
  /* Arrays */
  double         *a = 0;
  /* Nag Types */
  Nag_OrderType  order = Nag_ColMajor;
  NagError       fail;
  
  INIT_FAIL(fail);

  /* Output preamble */
  printf("nag_matop_real_gen_matrix_cond_sqrt (f01jdc) ");
  printf("Example Program Results\n\n");
  fflush(stdout);
  
  /* 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 = 0; i < n; i++)
    for (j = 0; j < n; j++) scanf("%lf", &A(i, j));
  scanf("%*[^\n] ");
  
  /* Find matrix square root, condition number and residual bound using
   * nag_matop_real_gen_matrix_cond_sqrt (f01jdc) 
   * Condition number for the square root of a real matrix
   */
  nag_matop_real_gen_matrix_cond_sqrt (n, a, pda, &alpha, &condsa, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_matop_real_gen_matrix_cond_sqrt (f01jdc)\n%s\n",
           fail.message);
    exit_status = 1;
    goto END;
  }
  
  /* Print matrix sqrt(A) 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, "sqrt(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;
  }

  /* Print condition number estimates */
  printf("Estimated relative condition number is: %7.2f\n", condsa); 
  printf("Condition number for the relative residual is: %7.2f\n",alpha);
  
 END:
  NAG_FREE(a);
  return exit_status;
}