URECommons.h

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/*
 * RECommons.h
 *
 * Copyright (C) 2014 Misgana Bayetta
 *
 * Author: Misgana Bayetta <misgana.bayetta@gmail.com>  Oct 2014
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License v3 as
 * published by the Free Software Foundation and including the exceptions
 * at http://opencog.org/wiki/Licenses
 *
 * This program 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 Affero General Public License
 * along with this program; if not, write to:
 * Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
#ifndef PLNCOMMONS_H_
#define PLNCOMMONS_H_

#include <opencog/util/dorepeat.h>
#include <opencog/util/random.h>

#include <opencog/atomspace/AtomSpace.h>
#include <opencog/atomspace/Handle.h>
#include <opencog/atomspace/types.h>

namespace opencog {

using namespace std;

class URECommons {
    AtomSpace& _as;

public:
    const float FITNESS_PARAM = 0.9;
    URECommons(AtomSpace& as);

    Handle create_bindLink(Handle himplicant, bool is_quoted = false)
            throw (opencog::InvalidParamException);

    bool exists_in(Handle& hlink, Handle& h);

    /*
     * Generate UUID
     */
    string get_unique_name(Handle& h);

    Handle replace_nodes_with_varnode(Handle& himplication_link, Type t =
            VARIABLE_NODE);

    Handle change_node_types(Handle& h, map<Handle, Handle>& replacement_map);

    void get_root_links(Handle h, HandleSeq& parents);

    template<class Type>
    Type tournament_select(map<Type, float> tfitnes_map) {
        // Nothing to select, return the nullptr rule
        if (tfitnes_map.empty())
            return Type();

        // Something to select, randomly pick (without replacement)
        // about half of the rules and return the best
        // TODO change the way pick_size is calculated
        size_t pick_size = std::max(static_cast<size_t>(1),
                tfitnes_map.size() / 2);
        multimap<float, Type> winners;
        dorepeat(pick_size)
        {
            auto el = rand_element(tfitnes_map);
            winners.insert( { el.second, el.first });
        }
        return winners.rbegin()->second;
    }
    float tv_fitness(Handle h);
};

} // ~namespace opencog

#endif /* PLNCOMMONS_H_ */