model_enumerators.h

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// 
// Copyright (c) 2006-2011, Benjamin Kaufmann
// 
// This file is part of Clasp. See http://www.cs.uni-potsdam.de/clasp/ 
// 
// Clasp 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 2 of the License, or
// (at your option) any later version.
// 
// Clasp 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 Clasp; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
//
#ifndef CLASP_MODEL_ENUMERATORS_H
#define CLASP_MODEL_ENUMERATORS_H

#ifdef _MSC_VER
#pragma once
#endif

#include <clasp/enumerator.h>
#include <clasp/clause.h>

namespace Clasp { 


class ModelEnumerator : public Enumerator {
public:
        enum Strategy {
                strategy_auto      = 0, 
                strategy_backtrack = 1, 
                strategy_record    = 2  
        };
        enum ProjectOptions {
                project_enable_simple = 1, 
                project_use_heuristic = 2, 
                project_save_progress = 4, 
                project_enable_full   = 6, 
        };
        explicit ModelEnumerator(Strategy st = strategy_auto);
        ~ModelEnumerator();
        

        void     setStrategy(Strategy st = strategy_auto, uint32 projection = 0);
        bool     projectionEnabled()const { return project_ != 0; }
        Strategy strategy()         const { return static_cast<Strategy>(options_ & 3u); }
protected:
        bool   supportsRestarts() const { return optimize() || strategy() == strategy_record; }
        bool   supportsParallel() const { return !projectionEnabled() || strategy() != strategy_backtrack; }
        ConPtr doInit(SharedContext& ctx, MinimizeConstraint* m, int numModels);
private:
        enum { detect_strategy_flag = 4u, trivial_flag = 8u, strategy_opts_mask = 15u };
        class ModelFinder;
        class BacktrackFinder;
        class RecordFinder;
        class SolutionQueue;
        typedef SolutionQueue* QPtr;
        void    initProjection(SharedContext& ctx);
        void    addProjectVar(SharedContext& ctx, Var v, bool mark);
        uint32  numProjectionVars() const { return (uint32)project_->size(); }
        Var     projectVar(uint32 i)const { return (*project_)[i]; }
        uint32  projectOpts()       const { return options_ >> 4; }
        bool    detectStrategy()    const { return (options_ & detect_strategy_flag) == detect_strategy_flag; }
        bool    trivial()           const { return (options_ & trivial_flag) == trivial_flag; }
        QPtr    queue_;
        VarVec* project_;
        uint32  options_;
};

}
#endif