restart.hh

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/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Christian Schulte, 2009
 *
 *  Last modified:
 *     $Date: 2009-05-12 14:21:02 +0200 (Tue, 12 May 2009) $ by $Author: schulte $
 *     $Revision: 9063 $
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
 *
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#ifndef __GECODE_SEARCH_SEQUENTIAL_RESTART_HH__
#define __GECODE_SEARCH_SEQUENTIAL_RESTART_HH__

#include <gecode/search/sequential/dfs.hh>

namespace Gecode { namespace Search { namespace Sequential {

  class Restart : public DFS {
  protected:
    Space* root;
    Space* best;
  public:
    Restart(Space* s, size_t sz, const Search::Options& o);
    Space* next(void);
    ~Restart(void);
  };

  forceinline 
  Restart::Restart(Space* s, size_t sz, const Search::Options& o) :
    DFS(s,sz,o),
    root(s->status() == SS_FAILED ? NULL : s->clone()), best(NULL) {}

  forceinline Space*
  Restart::next(void) {
    if (best != NULL) {
      root->constrain(*best);
      root = reset(root);
    }
    if (root == NULL)
      return NULL;
    delete best;
    best = DFS::next();
    return (best != NULL) ? best->clone() : NULL;
  }

  forceinline 
  Restart::~Restart(void) {
    delete best;
    delete root;
  }

}}}

#endif

// STATISTICS: search-sequential