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Diffstat (limited to 'casa/search/GreedyFilter.H')
-rw-r--r-- | casa/search/GreedyFilter.H | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/casa/search/GreedyFilter.H b/casa/search/GreedyFilter.H new file mode 100644 index 0000000..47ddef4 --- /dev/null +++ b/casa/search/GreedyFilter.H @@ -0,0 +1,64 @@ +// Copyright 2008, 2009 Brady J. Garvin + +// This file is part of Covering Arrays by Simulated Annealing (CASA). + +// CASA is free software: you can redistribute it and/or modify it +// under the terms of the GNU General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. + +// CASA 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 General Public License for more details. + +// You should have received a copy of the GNU General Public License +// along with CASA. If not, see <http://www.gnu.org/licenses/>. + + +#ifndef GREEDYFILTER_H +#define GREEDYFILTER_H + +#include "search/Filter.H" + +// A specialization of Filter where only the heuristically best child is +// explored. Furthermore, if given the option to treat the parent as a child, +// the filter will only have the search explore children if at least one of them +// is heuristically better than the parent. + +template<class STATE, class COST>class GreedyFilter : + public Filter<STATE, COST> { + typedef Heuristic<STATE, COST> HeuristicT; + typedef Goal<STATE> GoalT; + +public: + void operator() + (std::set<STATE>&children, const HeuristicT&heuristic, const GoalT&goal) + const { + typename std::set<STATE>::iterator best = children.end(); + COST score = 0; + for(typename std::set<STATE>::iterator + iterator = children.begin(), + end = children.end(); + iterator != end; + ++iterator) { + COST estimate = heuristic.estimate(*iterator, goal); + if (best == children.end() || estimate < score) { + best = iterator; + score = estimate; + } + } + for(typename std::set<STATE>::iterator + iterator = children.begin(), + end = children.end(); + iterator != end;){ + if (iterator == best) { + ++iterator; + } else { + children.erase(iterator++); + } + } + } +}; + +#endif |