TermSum.cc

/* 
 * File:   TermSum.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 "TermConstant.h"
#include "TermSum.h"
#include "TermVariable.h"
#include <sstream>
#include <typeinfo>

TermSum::TermSum(Problem* problem,
        Term* summand1, Term* summand2) :
TermBinary::TermBinary(problem) {
    if (summand1->less(summand2)) {
        this->summand1_ = summand1;
        this->summand2_ = summand2;
    } else {
        this->summand1_ = summand2;
        this->summand2_ = summand1;
    }
}

TermSum::~TermSum() {
}

Term* TermSum::create(Problem* problem,
        Term* summand1, Term* summand2) {
    TermSum* term;

    if (typeid (*summand1) == typeid (TermConstant) &&
            (static_cast<TermConstant *> (summand1))->evaluate() == 0) {
        return summand2;
    }
    if (typeid (*summand2) == typeid (TermConstant) &&
            (static_cast<TermConstant *> (summand2))->evaluate() == 0) {
        return summand1;
    }
    if (typeid (*summand1) == typeid (TermConstant) &&
            typeid (*summand2) == typeid (TermConstant)) {
        return TermConstant::create(problem,
                (static_cast<TermConstant *> (summand1))->evaluate() +
                (static_cast<TermConstant *> (summand2))->evaluate());
    }

    term = new TermSum(problem, summand1, summand2);
    term = static_cast<TermSum *> (problem->addTerm(term));
    return term;
}

Term* TermSum::differentiate(TermVariable* variable) throw
(ProblemMismatchException) {
    if (this->getProblem() != variable->getProblem()) {
        ProblemMismatchException problem_mismatch_exception;
        throw problem_mismatch_exception;
    }
    return TermSum::create(this->getProblem(),
            this->summand1_->differentiate(variable),
            this->summand2_->differentiate(variable)
            );
}

double TermSum::eval(const DoubleVector* variableValues,
        TermValueSet* termValues) {
    return this->summand1_->evaluate(variableValues, termValues) +
            this->summand2_->evaluate(variableValues, termValues);
}

bool TermSum::less(const Term* term) const {
    const TermSum* term_product;
    if (this->Term::less(term)) {
        return true;
    } else if (term->Term::less(this)) {
        return false;
    }
    term_product = static_cast<const TermSum *> (term);
    if (this->summand1_ < term_product->summand1_) {
        return true;
    } else if (term_product->summand1_ < this->summand1_) {
        return false;
    }
    if (this->summand2_ < term_product->summand2_) {
        return true;
    } else {
        return false;
    }
}

std::string TermSum::toString() const {
    std::ostringstream os;
    os << "(" << this->summand1_ << " + " << this->summand2_ << ")";
    return os.str();
}