dbl_eg_numutil.c

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/* EGlib "Efficient General Library" provides some basic structures and
 * algorithms commons in many optimization algorithms.
 *
 * Copyright (C) 2005 Daniel Espinoza and Marcos Goycoolea.
 * 
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA 
 * */
#include "dbl_eg_numutil.h"
/** @file
 * @ingroup EGlpNumUtil */
/** @addtogroup EGlpNumUtil */
/** @{ */
/* ========================================================================= */
void dbl_EGutilPermSort (const size_t sz,
                     int *const perm,
                     double * const elem)
{
  size_t i,
    j,
    temp;
  double t;
  if (sz <= 1)
    return;

  dbl_EGlpNumInitVar (t);
  EGswap (perm[0], perm[(sz - 1) / 2], temp);
  i = 0;
  j = sz;
  dbl_EGlpNumCopy (t, elem[perm[0]]);
  for (;;)
  {
    do
      i++;
    while (i < sz && dbl_EGlpNumIsLess (elem[perm[i]], t));
    do
      j--;
    while (dbl_EGlpNumIsLess (t, elem[perm[j]]));
    if (j < i)
      break;
    EGswap (perm[i], perm[j], temp);
  }
  EGswap (perm[0], perm[j], temp);
  dbl_EGlpNumClearVar (t);
  dbl_EGutilPermSort (j, perm, elem);
  dbl_EGutilPermSort (sz - i, perm + i, elem);
}

/* ========================================================================= */
void dbl_EGutilPermSort2 (const size_t sz,
                     int *const perm,
                     double * const elem)
{
  size_t i,
    j,
    temp;
  double t;
  if (sz <= 1)
    return;

  dbl_EGlpNumInitVar (t);
  EGswap (perm[0], perm[(sz - 1) / 2], temp);
  i = 0;
  j = sz;
  dbl_EGlpNumCopy (t, elem[perm[0]]);
  for (;;)
  {
    do
      i++;
    while (i < sz && dbl_EGlpNumIsLess (t, elem[perm[i]]));
    do
      j--;
    while (dbl_EGlpNumIsLess (elem[perm[j]], t));
    if (j < i)
      break;
    EGswap (perm[i], perm[j], temp);
  }
  EGswap (perm[0], perm[j], temp);
  dbl_EGlpNumClearVar (t);
  dbl_EGutilPermSort2 (j, perm, elem);
  dbl_EGutilPermSort2 (sz - i, perm + i, elem);
}

/* ========================================================================= */
/** @} */

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