include/dlvhex2/Nogood.h

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/* dlvhex -- Answer-Set Programming with external interfaces.
 * Copyright (C) 2005-2007 Roman Schindlauer
 * Copyright (C) 2006-2015 Thomas Krennwallner
 * Copyright (C) 2009-2016 Peter Schüller
 * Copyright (C) 2011-2016 Christoph Redl
 * Copyright (C) 2015-2016 Tobias Kaminski
 * Copyright (C) 2015-2016 Antonius Weinzierl
 *
 * This file is part of dlvhex.
 *
 * dlvhex 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.
 *
 * dlvhex 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 dlvhex; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA.
 */

#ifndef NOGOOD_HPP_INCLUDED__09122011
#define NOGOOD_HPP_INCLUDED__09122011

#include <vector>
#include <set>
#include <map>
#include <boost/foreach.hpp>
#include <boost/foreach.hpp>
#include <boost/unordered_map.hpp>

#include "dlvhex2/ID.h"
#include "dlvhex2/Printhelpers.h"
#include "dlvhex2/Set.h"
#include "dlvhex2/Registry.h"
#include "dlvhex2/Interpretation.h"

DLVHEX_NAMESPACE_BEGIN

class DLVHEX_EXPORT Nogood : public Set<ID>, public ostream_printable<Nogood>
{
    private:
        std::size_t hashValue;

        bool ground;

    public:
        Nogood();

        Nogood(InterpretationConstPtr assigned, InterpretationConstPtr interpretation);

        void recomputeHash();

        size_t getHash();

        const Nogood& operator=(const Nogood& other);

        bool operator==(const Nogood& ng2) const;

        bool operator!=(const Nogood& ng2) const;

        std::ostream& print(std::ostream& o) const;

        std::string getStringRepresentation(RegistryPtr reg) const;

        Nogood resolve(const Nogood& ng2, IDAddress groundlitadr);

        Nogood resolve(const Nogood& ng2, ID lit);

        void applyVariableSubstitution(RegistryPtr reg, const std::map<ID, ID>& subst);

        void heuristicNormalization(RegistryPtr reg);

        void insert(ID lit);
        template <class InputIterator> void insert(InputIterator begin, InputIterator end) {
            for (InputIterator it = begin; it != end; ++it) {
                insert(*it);
            }
        }

        bool isGround() const;

        bool match(RegistryPtr reg, ID atomID, Nogood& instance) const;

    #ifndef NDEBUG
        // saves the nogood as string or loads it back (for debug purposes)
        std::string dbgsave() const;
        void dbgload(std::string str);
    #endif
};

class DLVHEX_EXPORT NogoodSet : private ostream_printable<NogoodSet>
{
    private:
        std::vector<Nogood> nogoods;
        std::vector<int> addCount;
        Set<int> freeIndices;
        boost::unordered_map<size_t, Set<int> > nogoodsWithHash;

    public:
        void defragment();

        const NogoodSet& operator=(const NogoodSet& other);

        int addNogood(Nogood ng);

        void removeNogood(int nogoodIndex);

        void removeNogood(Nogood ng);

        Nogood& getNogood(int index);

        const Nogood& getNogood(int index) const;

        int getNogoodCount() const;

        void forgetLeastFrequentlyAdded();

        std::ostream& print(std::ostream& o) const;

        std::string getStringRepresentation(RegistryPtr reg) const;
};

class DLVHEX_EXPORT NogoodContainer
{
    public:
        virtual void addNogood(Nogood ng) = 0;

        static inline ID createLiteral(ID lit) {
            if (lit.isOrdinaryGroundAtom()) {
                return ID(ID::MAINKIND_LITERAL | ID::SUBKIND_ATOM_ORDINARYG | (lit.isNaf() ? ID::NAF_MASK : 0), lit.address);
            }
            else {
                return ID(ID::MAINKIND_LITERAL | ID::SUBKIND_ATOM_ORDINARYN | (lit.isNaf() ? ID::NAF_MASK : 0), lit.address);
            }
        }

        static inline ID createLiteral(IDAddress litadr, bool truthValue = true, bool ground = true) {
            if (ground) {
                return ID(ID::MAINKIND_LITERAL | ID::SUBKIND_ATOM_ORDINARYG | (truthValue ? 0 : ID::NAF_MASK), litadr);
            }
            else {
                return ID(ID::MAINKIND_LITERAL | ID::SUBKIND_ATOM_ORDINARYN | (truthValue ? 0 : ID::NAF_MASK), litadr);
            }
        }

        typedef boost::shared_ptr<NogoodContainer> Ptr;
        typedef boost::shared_ptr<const NogoodContainer> ConstPtr;
};

typedef NogoodContainer::Ptr NogoodContainerPtr;
typedef NogoodContainer::ConstPtr NogoodContainerConstPtr;

class DLVHEX_EXPORT SimpleNogoodContainer : public NogoodContainer
{
    private:
        boost::mutex mutex;

        NogoodSet ngg;
    public:
        void addNogood(Nogood ng);
        void removeNogood(Nogood ng);
        Nogood& getNogood(int index);
        int getNogoodCount();
        void clear();
        void addAllResolvents(RegistryPtr reg, int maxSize = -1);

        void forgetLeastFrequentlyAdded();
        void defragment();

        typedef boost::shared_ptr<SimpleNogoodContainer> Ptr;
        typedef boost::shared_ptr<const SimpleNogoodContainer> ConstPtr;
};

typedef SimpleNogoodContainer::Ptr SimpleNogoodContainerPtr;
typedef SimpleNogoodContainer::ConstPtr SimpleNogoodContainerConstPtr;

DLVHEX_NAMESPACE_END
#endif

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