/* nag_zsycon (f07nuc) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

#include <stdio.h>
#include <nag.h>
#include <nagx04.h>
#include <nag_stdlib.h>
#include <naga02.h>
#include <nagf07.h>
#include <nagf16.h>
#include <nagx02.h>

int main(int argc, char *argv[])
{
  FILE          *fpin, *fpout;
  /* Scalars */
  double        anorm, rcond;
  Integer       i, j, n, pda;
  Integer       exit_status = 0;
  Nag_UploType  uplo;
  NagError      fail;
  Nag_OrderType order;
  /* Arrays */
  Integer       *ipiv = 0;
  char          nag_enum_arg[40];
  Complex       *a = 0;

#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);

  /* Check for command-line IO options */
  fpin = nag_example_file_io(argc, argv, "-data", NULL);
  fpout = nag_example_file_io(argc, argv, "-results", NULL);
  fprintf(fpout, "nag_zsycon (f07nuc) Example Program Results\n\n");

  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n] ");
  fscanf(fpin, "%ld%*[^\n] ", &n);
#ifdef NAG_COLUMN_MAJOR
  pda = n;
#else
  pda = n;
#endif

  /* Allocate memory */
  if (!(ipiv = NAG_ALLOC(n, Integer)) ||
      !(a = NAG_ALLOC(n * n, Complex)))
    {
      fprintf(fpout, "Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Read A from data file */
  fscanf(fpin, " %s%*[^\n] ", nag_enum_arg);
  /* nag_enum_name_to_value(x04nac).
   * Converts NAG enum member name to value
   */
  uplo = (Nag_UploType) nag_enum_name_to_value(nag_enum_arg);

  if (uplo == Nag_Upper)
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = i; j <= n; ++j)
            fscanf(fpin, " ( %lf , %lf )", &A(i, j).re, &A(i, j).im);
        }
      fscanf(fpin, "%*[^\n] ");
    }
  else
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = 1; j <= i; ++j)
            fscanf(fpin, " ( %lf , %lf )", &A(i, j).re, &A(i, j).im);
        }
      fscanf(fpin, "%*[^\n] ");
    }

  /* Compute norm of A */
  /* nag_zsy_norm (f16ufc).
   * 1-norm, infinity-norm, Frobenius norm, largest absolute
   * element, complex symmetric matrix
   */
  nag_zsy_norm(order, Nag_OneNorm, uplo, n, a, pda, &anorm, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_zsy_norm (f16ufc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Factorize A */

  /* nag_zsytrf (f07nrc).
   * Bunch-Kaufman factorization of complex symmetric matrix
   */
  nag_zsytrf(order, uplo, n, a, pda, ipiv, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_zsytrf (f07nrc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Estimate condition number */
  /* nag_zsycon (f07nuc).
   * Estimate condition number of complex symmetric matrix,
   * matrix already factorized by nag_zsytrf (f07nrc)
   */
  nag_zsycon(order, uplo, n, a, pda, ipiv, anorm, &rcond,
             &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_zsycon (f07nuc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* nag_machine_precision (x02ajc).
   * The machine precision
   */
  if (rcond >= X02AJC)
    fprintf(fpout, "Estimate of condition number =%11.2e\n", 1.0/rcond);
  else
    fprintf(fpout, "A is singular to working precision\n");
 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  if (ipiv) NAG_FREE(ipiv);
  if (a) NAG_FREE(a);
  return exit_status;
}