/* nag_dtrsna (f08qlc) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagf08.h>
#include <nagf16.h>
#include <nagx02.h>

int main(void)
{
  /* Scalars */
  Integer  i, j, m, n, pdt, pdvl, pdvr;
  Integer  select_len, s_len;
  Integer  exit_status=0;
  double   eps, tnorm;
  NagError fail;
  Nag_OrderType order;
  /* Arrays */
  double  *s=0, *sep=0, *t=0, *vl=0, *vr=0;
  Boolean *select=0;

#ifdef NAG_COLUMN_MAJOR
#define T(I,J) t[(J-1)*pdt + I - 1]
  order = Nag_ColMajor;
#else
#define T(I,J) t[(I-1)*pdt + J - 1]
  order = Nag_RowMajor;
#endif

  INIT_FAIL(fail);
  Vprintf("f08qlc Example Program Results\n");

  /* Skip heading in data file */
  Vscanf("%*[^\n] ");
  Vscanf("%ld%*[^\n] ", &n);
#ifdef NAG_COLUMN_MAJOR
  pdt = n;
  pdvl = n;
  pdvr = n;
#else
  pdt = n;
  pdvl = n;
  pdvr = n;
#endif
  select_len = 1;
  s_len = n;

  /* Allocate memory */
  if ( !(t = NAG_ALLOC(n * n, double)) ||
       !(vl = NAG_ALLOC(n * n, double)) ||
       !(vr = NAG_ALLOC(n * n, double)) ||
       !(s = NAG_ALLOC(s_len, double)) ||
       !(sep = NAG_ALLOC(s_len, double)) ||
       !(select = NAG_ALLOC(select_len, Boolean)) )
    {
      Vprintf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Read T from data file */
  for (i = 1; i <= n; ++i)
    {
      for (j = 1; j <= n; ++j)
        Vscanf("%lf", &T(i,j));
    }
  Vscanf("%*[^\n] ");

  /* Calculate right and left eigrnvectors of T */
  f08qkc(order, Nag_BothSides, Nag_ComputeAll, select, n, t, pdt,
         vl, pdvl, vr, pdvr, n, &m, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from f08qkc.\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Estimate condition numbers for all the eigenvalues and */
  /* right eigenvectors of T */
  f08qlc(order, Nag_DoBoth, Nag_ComputeAll, select, n, t, pdt,
         vl, pdvl, vr, pdvr, s, sep, n, &m, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from f08qlc.\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print condition numbers of eigenvalues and right eigenvectors */
  Vprintf("\nS\n");
  for (i = 0; i < n; ++i)
    Vprintf("%11.1e", s[i]);
  Vprintf("\n\nSep\n");
  for (i = 0; i < n; ++i)
    Vprintf("%11.1e", sep[i]);
  Vprintf("\n");
  /* Calculate approximate error estimates (using the 1-norm) */
  f16rac(order, Nag_OneNorm, n, n, t, pdt, &tnorm, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from f16rac.\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  eps = X02AJC;
  Vprintf("\nApproximate error estimates for eigenvalues"
          "of T (machine dependent)\n");
  for (i = 0; i < m; ++i)
    Vprintf("%11.1e", eps*tnorm/s[i]);
  Vprintf("\n\nApproximate error estimates for right eigenvectors"
          "of T (machine dependent)\n");
  for (i = 0; i < m; ++i)
    Vprintf("%11.1e", eps*tnorm/sep[i]);
  Vprintf("\n");
 END:
  if (t) NAG_FREE(t);
  if (s) NAG_FREE(s);
  if (sep) NAG_FREE(sep);
  if (vl) NAG_FREE(vl);
  if (vr) NAG_FREE(vr);
  if (select) NAG_FREE(select);

  return exit_status;
}