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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.

A linear objective function has one the form:

c1x1 + ... cnxn + d
The ci and d are the coefficients of the equation, the xi are the coordinates of the current point.

Deprecated:As of 3.1 (to be removed in 4.0).
Since:2.0
/** * 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.
/** Serializable version identifier. */
private static final long serialVersionUID = -4531815507568396090L;
Coefficients of the constraint (ci).
/** Coefficients of the constraint (c<sub>i</sub>). */
private final transient RealVector coefficients;
Constant term of the linear equation.
/** Constant term of the linear equation. */
private final double constantTerm;
Params:
  • coefficients – The coefficients for the linear equation being optimized
  • constantTerm – The constant term of the linear equation
/** * @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); }
Params:
  • coefficients – The coefficients for the linear equation being optimized
  • constantTerm – The constant term of the linear equation
/** * @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.
Returns:coefficients of the linear equation being optimized
/** * 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.
Returns:constant of the linear equation being optimized
/** * 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
Params:
  • point – point at which linear equation must be evaluated
Returns:value of the linear equation at the current point
/** * 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
Params:
  • point – point at which linear equation must be evaluated
Returns:value of the linear equation at the current point
/** * 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; }
{@inheritDoc}
/** {@inheritDoc} */
@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; }
{@inheritDoc}
/** {@inheritDoc} */
@Override public int hashCode() { return Double.valueOf(constantTerm).hashCode() ^ coefficients.hashCode(); }
Serialize the instance.
Params:
  • oos – stream where object should be written
Throws:
/** * 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.
Params:
  • ois – stream from which the object should be read
Throws:
/** * 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); } }