TermSign.cc

/* 
 * File:   TermSign.cc
 * 
 * Copyright 2012 Heinrich Schuchardt <xypron.glpk@gmx.de>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "Problem.h"
#include "TermSign.h"
#include "TermConstant.h"
#include <sstream>

TermSign::TermSign(Problem* problem, Term *term) :
Term::Term(problem) {
    term_ = term;
}

TermSign::~TermSign() {
}

TermSign* TermSign::create(Problem* problem, Term *term) throw
(ProblemMismatchException) {
    TermSign* ret = new TermSign(problem, term);
    ret = static_cast<TermSign*> (problem->addTerm(ret));
    return ret;
}

Term* TermSign::differentiate(TermVariable* variable) throw
(ProblemMismatchException) {
    return TermConstant::create(this->getProblem(), 0);
}

double TermSign::eval(
        const DoubleVector* variableValues,
        TermValueSet* termValues) {
    double value = this->term_->evaluate(variableValues, termValues);
    if (value > 0) {
        return 1.;
    } else if (value < 0) {
        return -1.;
    } else {
        return 0.;
    }
}

bool TermSign::less(const Term* term) const {
    if (this->Term::less(term)) {
        return true;
    } else if (term->Term::less(this)) {
        return false;
    } else {
        const TermSign* term_sign;
        term_sign = static_cast<const TermSign *> (term);
        return this->term_->less(term_sign->term_);
    }
}

std::string TermSign::toString() const {
    std::ostringstream os;
    os << "sgn(" << term_->toString() << ")";
    return os.str();
};