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/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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. */ package org.apache.commons.math3.optim.linear; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.Serializable; import org.apache.commons.math3.linear.MatrixUtils; import org.apache.commons.math3.linear.RealVector; import org.apache.commons.math3.linear.ArrayRealVector; /** * A linear constraint for a linear optimization problem. * <p> * A linear constraint has one of the forms: * <ul> * <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> = v</li> * <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> <= v</li> * <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> >= v</li> * <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> = * r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li> * <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> <= * r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li> * <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> >= * r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li> * </ul> * The c<sub>i</sub>, l<sub>i</sub> or r<sub>i</sub> are the coefficients of the constraints, the x<sub>i</sub> * are the coordinates of the current point and v is the value of the constraint. * </p> * * @version $Id: LinearConstraint.java 1416643 2012-12-03 19:37:14Z tn $ * @since 2.0 */ public class LinearConstraint implements Serializable { /** Serializable version identifier. */ private static final long serialVersionUID = -764632794033034092L; /** Coefficients of the constraint (left hand side). */ private final transient RealVector coefficients; /** Relationship between left and right hand sides (=, <=, >=). */ private final Relationship relationship; /** Value of the constraint (right hand side). */ private final double value; /** * Build a constraint involving a single linear equation. * <p> * A linear constraint with a single linear equation has one of the forms: * <ul> * <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> = v</li> * <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> <= v</li> * <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> >= v</li> * </ul> * </p> * @param coefficients The coefficients of the constraint (left hand side) * @param relationship The type of (in)equality used in the constraint * @param value The value of the constraint (right hand side) */ public LinearConstraint(final double[] coefficients, final Relationship relationship, final double value) { this(new ArrayRealVector(coefficients), relationship, value); } /** * Build a constraint involving a single linear equation. * <p> * A linear constraint with a single linear equation has one of the forms: * <ul> * <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> = v</li> * <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> <= v</li> * <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> >= v</li> * </ul> * </p> * @param coefficients The coefficients of the constraint (left hand side) * @param relationship The type of (in)equality used in the constraint * @param value The value of the constraint (right hand side) */ public LinearConstraint(final RealVector coefficients, final Relationship relationship, final double value) { this.coefficients = coefficients; this.relationship = relationship; this.value = value; } /** * Build a constraint involving two linear equations. * <p> * A linear constraint with two linear equation has one of the forms: * <ul> * <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> = * r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li> * <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> <= * r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li> * <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> >= * r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li> * </ul> * </p> * @param lhsCoefficients The coefficients of the linear expression on the left hand side of the constraint * @param lhsConstant The constant term of the linear expression on the left hand side of the constraint * @param relationship The type of (in)equality used in the constraint * @param rhsCoefficients The coefficients of the linear expression on the right hand side of the constraint * @param rhsConstant The constant term of the linear expression on the right hand side of the constraint */ public LinearConstraint(final double[] lhsCoefficients, final double lhsConstant, final Relationship relationship, final double[] rhsCoefficients, final double rhsConstant) { double[] sub = new double[lhsCoefficients.length]; for (int i = 0; i < sub.length; ++i) { sub[i] = lhsCoefficients[i] - rhsCoefficients[i]; } this.coefficients = new ArrayRealVector(sub, false); this.relationship = relationship; this.value = rhsConstant - lhsConstant; } /** * Build a constraint involving two linear equations. * <p> * A linear constraint with two linear equation has one of the forms: * <ul> * <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> = * r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li> * <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> <= * r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li> * <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> >= * r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li> * </ul> * </p> * @param lhsCoefficients The coefficients of the linear expression on the left hand side of the constraint * @param lhsConstant The constant term of the linear expression on the left hand side of the constraint * @param relationship The type of (in)equality used in the constraint * @param rhsCoefficients The coefficients of the linear expression on the right hand side of the constraint * @param rhsConstant The constant term of the linear expression on the right hand side of the constraint */ public LinearConstraint(final RealVector lhsCoefficients, final double lhsConstant, final Relationship relationship, final RealVector rhsCoefficients, final double rhsConstant) { this.coefficients = lhsCoefficients.subtract(rhsCoefficients); this.relationship = relationship; this.value = rhsConstant - lhsConstant; } /** * Gets the coefficients of the constraint (left hand side). * * @return the coefficients of the constraint (left hand side). */ public RealVector getCoefficients() { return coefficients; } /** * Gets the relationship between left and right hand sides. * * @return the relationship between left and right hand sides. */ public Relationship getRelationship() { return relationship; } /** * Gets the value of the constraint (right hand side). * * @return the value of the constraint (right hand side). */ public double getValue() { return value; } @Override public boolean equals(Object other) { if (this == other) { return true; } if (other instanceof LinearConstraint) { LinearConstraint rhs = (LinearConstraint) other; return relationship == rhs.relationship && value == rhs.value && coefficients.equals(rhs.coefficients); } return false; } @Override public int hashCode() { return relationship.hashCode() ^ Double.valueOf(value).hashCode() ^ coefficients.hashCode(); } /** * Serialize the instance. * @param oos stream where object should be written * @throws IOException if object cannot be written to stream */ private void writeObject(ObjectOutputStream oos) throws IOException { oos.defaultWriteObject(); MatrixUtils.serializeRealVector(coefficients, oos); } /** * Deserialize the instance. * @param ois stream from which the object should be read * @throws ClassNotFoundException if a class in the stream cannot be found * @throws IOException if object cannot be read from the stream */ private void readObject(ObjectInputStream ois) throws ClassNotFoundException, IOException { ois.defaultReadObject(); MatrixUtils.deserializeRealVector(this, "coefficients", ois); } }