AttentionalFocusCB.cc

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/*
 * AttentionalFocusCB.cc
 *
 * Copyright (C) 2014 Misgana Bayetta
 *
 * Author: Misgana Bayetta <misgana.bayetta@gmail.com>  July 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.
 */
#include "AttentionalFocusCB.h"

using namespace opencog;

// Uncomment below to enable debug print
// #define DEBUG
#ifdef DEBUG
   #define dbgprt(f, varargs...) printf(f, ##varargs)
#else
   #define dbgprt(f, varargs...)
#endif

AttentionalFocusCB::AttentionalFocusCB(AtomSpace* as) :
    DefaultPatternMatchCB(as)
{
    // Temporarily disable the AF mechanism during the URE development
    // _as->setAttentionalFocusBoundary(AttentionValue::MINSTI);
}

bool AttentionalFocusCB::node_match(const Handle& node1, const Handle& node2)
{
    return node1 == node2 and
        node2->getSTI() > _as->get_attentional_focus_boundary();
}

bool AttentionalFocusCB::link_match(const LinkPtr& lpat, const LinkPtr& lsoln)
{
    return DefaultPatternMatchCB::link_match(lpat, lsoln)
        and lsoln->getSTI() > _as->get_attentional_focus_boundary();
}

IncomingSet AttentionalFocusCB::get_incoming_set(const Handle& h)
{
    const IncomingSet &incoming_set = h->getIncomingSet();

    // Discard the part of the incoming set that is below the
    // AF boundary.  The PM will look only at those links that
    // this callback returns; thus we avoid searching the low-AF
    // parts of the hypergraph.
    IncomingSet filtered_set;
    for (const auto& l : incoming_set)
        if (l->getSTI() > _as->get_attentional_focus_boundary())
            filtered_set.push_back(l);

    // If nothing is in AF
    if (filtered_set.empty())
    {
        // Returning the empty set abandons the search in this direction.
        // Search will then backtrack and try a different direction.
        // ... and that is exactly what should be happening.
        return filtered_set;
    }

    // The exploration of the set of patterns proceeds by going through
    // the incoming set, one by one.  So sorting the incoming set will
    // cause the exploration to look at the highest STI atoms first.
    std::sort(filtered_set.begin(), filtered_set.end(), compare_sti);

    return filtered_set;
}