TimesLink.cc

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/*
 * opencog/atoms/reduct/TimesLink.cc
 *
 * Copyright (C) 2015 Linas Vepstas
 * All Rights Reserved
 *
 * 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 Times 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:
 * Times Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <opencog/atomspace/atom_types.h>
#include <opencog/atomspace/ClassServer.h>
#include <opencog/atoms/NumberNode.h>
#include "TimesLink.h"

using namespace opencog;

TimesLink::TimesLink(const HandleSeq& oset,
                   TruthValuePtr tv,
                   AttentionValuePtr av)
    : ArithmeticLink(TIMES_LINK, oset, tv, av)
{
    init();
}

TimesLink::TimesLink(Type t, const HandleSeq& oset,
                   TruthValuePtr tv,
                   AttentionValuePtr av)
    : ArithmeticLink(t, oset, tv, av)
{
    if (not classserver().isA(t, TIMES_LINK))
        throw InvalidParamException(TRACE_INFO, "Expecting a TimesLink");
    init();
}

TimesLink::TimesLink(Type t, const Handle& a, const Handle& b,
                   TruthValuePtr tv,
                   AttentionValuePtr av)
    : ArithmeticLink(t, a, b, tv, av)
{
    if (not classserver().isA(t, TIMES_LINK))
        throw InvalidParamException(TRACE_INFO, "Expecting a TimesLink");
    init();
}

TimesLink::TimesLink(const Handle& a, const Handle& b,
                   TruthValuePtr tv,
                   AttentionValuePtr av)
    : ArithmeticLink(TIMES_LINK, a, b, tv, av)
{
    init();
}

TimesLink::TimesLink(Link& l)
    : ArithmeticLink(l)
{
    Type tscope = l.getType();
    if (not classserver().isA(tscope, TIMES_LINK))
        throw InvalidParamException(TRACE_INFO, "Expecting a TimesLink");
    init();
}

void TimesLink::init(void)
{
    knild = 1.0;
    knil = Handle(createNumberNode("1"));
}

// ============================================================

double TimesLink::konsd(double a, double b) const { return a*b; }

static inline double get_double(const Handle& h)
{
    NumberNodePtr nnn(NumberNodeCast(h));
    if (NULL == nnn)
        nnn = createNumberNode(*NodeCast(h));

    return nnn->get_value();
}

Handle TimesLink::kons(const Handle& fi, const Handle& fj)
{
    // Are they numbers?
    if (NUMBER_NODE == fi->getType() and
        NUMBER_NODE == fj->getType())
    {
        double prod = get_double(fi) * get_double(fj);
        return Handle(createNumberNode(prod));
    }

    // If we are here, we've been asked to multiply two things of the
    // same type, but they are not of a type that we know how to multiply.
    return Handle(createTimesLink(fi, fj)->reorder());
}

// ============================================================