/*
* 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.optimization.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;
/**
* An objective function for a linear optimization problem.
* <p>
* A linear objective function has one the form:
* <pre>
* c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> + d
* </pre>
* The c<sub>i</sub> and d are the coefficients of the equation,
* the x<sub>i</sub> are the coordinates of the current point.
* </p>
* @deprecated As of 3.1 (to be removed in 4.0).
* @since 2.0
*/
@Deprecated
public class LinearObjectiveFunction implements Serializable {
/** Serializable version identifier. */
private static final long serialVersionUID = -4531815507568396090L;
/** Coefficients of the constraint (c<sub>i</sub>). */
private final transient RealVector coefficients;
/** Constant term of the linear equation. */
private final double constantTerm;
/**
* @param coefficients The coefficients for the linear equation being optimized
* @param constantTerm The constant term of the linear equation
*/
public LinearObjectiveFunction(double[] coefficients, double constantTerm) {
this(new ArrayRealVector(coefficients), constantTerm);
}
/**
* @param coefficients The coefficients for the linear equation being optimized
* @param constantTerm The constant term of the linear equation
*/
public LinearObjectiveFunction(RealVector coefficients, double constantTerm) {
this.coefficients = coefficients;
this.constantTerm = constantTerm;
}
/**
* Get the coefficients of the linear equation being optimized.
* @return coefficients of the linear equation being optimized
*/
public RealVector getCoefficients() {
return coefficients;
}
/**
* Get the constant of the linear equation being optimized.
* @return constant of the linear equation being optimized
*/
public double getConstantTerm() {
return constantTerm;
}
/**
* Compute the value of the linear equation at the current point
* @param point point at which linear equation must be evaluated
* @return value of the linear equation at the current point
*/
public double getValue(final double[] point) {
return coefficients.dotProduct(new ArrayRealVector(point, false)) + constantTerm;
}
/**
* Compute the value of the linear equation at the current point
* @param point point at which linear equation must be evaluated
* @return value of the linear equation at the current point
*/
public double getValue(final RealVector point) {
return coefficients.dotProduct(point) + constantTerm;
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (other instanceof LinearObjectiveFunction) {
LinearObjectiveFunction rhs = (LinearObjectiveFunction) other;
return (constantTerm == rhs.constantTerm) && coefficients.equals(rhs.coefficients);
}
return false;
}
@Override
public int hashCode() {
return Double.valueOf(constantTerm).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);
}
}