NTMonomial.java

/*******************************************************************************
 * Copyright (c) 2013 Stephen F. Siegel, University of Delaware.
 * 
 * This file is part of SARL.
 * 
 * SARL is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option) any
 * later version.
 * 
 * SARL 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 Lesser General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with SARL. If not, see <http://www.gnu.org/licenses/>.
 ******************************************************************************/
package edu.udel.cis.vsl.sarl.ideal.common;

import edu.udel.cis.vsl.sarl.collections.IF.SymbolicMap;
import edu.udel.cis.vsl.sarl.ideal.IF.Constant;
import edu.udel.cis.vsl.sarl.ideal.IF.IdealFactory;
import edu.udel.cis.vsl.sarl.ideal.IF.Monic;
import edu.udel.cis.vsl.sarl.ideal.IF.Monomial;
import edu.udel.cis.vsl.sarl.ideal.IF.Polynomial;

/**
 * A non-trivial monomial is the product of a constant and a monic. The constant
 * must not be 0 or 1 and the monic must not be empty.
 * 
 * @author siegel
 * 
 */
public class NTMonomial extends IdealExpression implements Monomial {

	private SymbolicMap<Monic, Monomial> termMap = null;

	protected NTMonomial(Constant constant, Monic monic) {
		super(SymbolicOperator.MULTIPLY, constant.type(), constant, monic);
		assert !constant.isZero();
		assert !constant.isOne();
		assert !monic.isOne();
	}

	@Override
	public Monic monic(IdealFactory factory) {
		return (Monic) argument(1);
	}

	public Monic monic() {
		return (Monic) argument(1);
	}

	@Override
	public SymbolicMap<Monic, Monomial> termMap(IdealFactory factory) {
		if (termMap == null)
			termMap = factory
					.singletonMap((Monic) argument(1), (Monomial) this);
		return termMap;
	}

	@Override
	public Constant monomialConstant(IdealFactory factory) {
		return (Constant) argument(0);
	}

	public Constant monomialConstant() {
		return (Constant) argument(0);
	}

	@Override
	public Monomial factorization(IdealFactory factory) {
		return this;
	}

	@Override
	public Polynomial numerator(IdealFactory factory) {
		return this;
	}

	@Override
	public Polynomial denominator(IdealFactory factory) {
		return factory.one(type());
	}

	@Override
	public Monomial leadingTerm() {
		return this;
	}

	@Override
	public Polynomial expand(IdealFactory factory) {
		Monic monic = this.monic();
		Polynomial expandedMonic = monic.expand(factory);

		if (monic == expandedMonic)
			return this;
		return factory.multiply(monomialConstant(), expandedMonic);
	}

//	@Override
//	public String toString() {
//		return monomialConstant().toString() + monic().toString();
//	}

	@Override
	public int degree() {
		return monic().degree();
	}

	@Override
	public IdealKind idealKind() {
		return IdealKind.NTMonomial;
	}

	@Override
	public Constant constantTerm(IdealFactory factory) {
		return factory.zero(type());
	}

}