LinearConstraint.java

  1. /*
  2.  * Licensed to the Apache Software Foundation (ASF) under one or more
  3.  * contributor license agreements.  See the NOTICE file distributed with
  4.  * this work for additional information regarding copyright ownership.
  5.  * The ASF licenses this file to You under the Apache License, Version 2.0
  6.  * (the "License"); you may not use this file except in compliance with
  7.  * the License.  You may obtain a copy of the License at
  8.  *
  9.  *      http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */

  18. package org.apache.commons.math3.optimization.linear;

  20. import java.io.IOException;
  21. import java.io.ObjectInputStream;
  22. import java.io.ObjectOutputStream;
  23. import java.io.Serializable;

  25. import org.apache.commons.math3.linear.MatrixUtils;
  26. import org.apache.commons.math3.linear.RealVector;
  27. import org.apache.commons.math3.linear.ArrayRealVector;


  30. /**
  31.  * A linear constraint for a linear optimization problem.
  32.  * <p>
  33.  * A linear constraint has one of the forms:
  34.  * <ul>
  35.  *   <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> = v</li>
  36.  *   <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> &lt;= v</li>
  37.  *   <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> >= v</li>
  38.  *   <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> =
  39.  *       r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li>
  40.  *   <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> &lt;=
  41.  *       r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li>
  42.  *   <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> >=
  43.  *       r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li>
  44.  * </ul>
  45.  * 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>
  46.  * are the coordinates of the current point and v is the value of the constraint.
  47.  * </p>
  48.  * @deprecated As of 3.1 (to be removed in 4.0).
  49.  * @since 2.0
  50.  */
  51. @Deprecated
  52. public class LinearConstraint implements Serializable {

  54.     /** Serializable version identifier. */
  55.     private static final long serialVersionUID = -764632794033034092L;

  57.     /** Coefficients of the constraint (left hand side). */
  58.     private final transient RealVector coefficients;

  60.     /** Relationship between left and right hand sides (=, &lt;=, >=). */
  61.     private final Relationship relationship;

  63.     /** Value of the constraint (right hand side). */
  64.     private final double value;

  66.     /**
  67.      * Build a constraint involving a single linear equation.
  68.      * <p>
  69.      * A linear constraint with a single linear equation has one of the forms:
  70.      * <ul>
  71.      *   <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> = v</li>
  72.      *   <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> &lt;= v</li>
  73.      *   <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> >= v</li>
  74.      * </ul>
  75.      * </p>
  76.      * @param coefficients The coefficients of the constraint (left hand side)
  77.      * @param relationship The type of (in)equality used in the constraint
  78.      * @param value The value of the constraint (right hand side)
  79.      */
  80.     public LinearConstraint(final double[] coefficients, final Relationship relationship,
  81.                             final double value) {
  82.         this(new ArrayRealVector(coefficients), relationship, value);
  83.     }

  85.     /**
  86.      * Build a constraint involving a single linear equation.
  87.      * <p>
  88.      * A linear constraint with a single linear equation has one of the forms:
  89.      * <ul>
  90.      *   <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> = v</li>
  91.      *   <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> &lt;= v</li>
  92.      *   <li>c<sub>1</sub>x<sub>1</sub> + ... c<sub>n</sub>x<sub>n</sub> >= v</li>
  93.      * </ul>
  94.      * </p>
  95.      * @param coefficients The coefficients of the constraint (left hand side)
  96.      * @param relationship The type of (in)equality used in the constraint
  97.      * @param value The value of the constraint (right hand side)
  98.      */
  99.     public LinearConstraint(final RealVector coefficients, final Relationship relationship,
  100.                             final double value) {
  101.         this.coefficients = coefficients;
  102.         this.relationship = relationship;
  103.         this.value        = value;
  104.     }

  106.     /**
  107.      * Build a constraint involving two linear equations.
  108.      * <p>
  109.      * A linear constraint with two linear equation has one of the forms:
  110.      * <ul>
  111.      *   <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> =
  112.      *       r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li>
  113.      *   <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> &lt;=
  114.      *       r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li>
  115.      *   <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> >=
  116.      *       r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li>
  117.      * </ul>
  118.      * </p>
  119.      * @param lhsCoefficients The coefficients of the linear expression on the left hand side of the constraint
  120.      * @param lhsConstant The constant term of the linear expression on the left hand side of the constraint
  121.      * @param relationship The type of (in)equality used in the constraint
  122.      * @param rhsCoefficients The coefficients of the linear expression on the right hand side of the constraint
  123.      * @param rhsConstant The constant term of the linear expression on the right hand side of the constraint
  124.      */
  125.     public LinearConstraint(final double[] lhsCoefficients, final double lhsConstant,
  126.                             final Relationship relationship,
  127.                             final double[] rhsCoefficients, final double rhsConstant) {
  128.         double[] sub = new double[lhsCoefficients.length];
  129.         for (int i = 0; i < sub.length; ++i) {
  130.             sub[i] = lhsCoefficients[i] - rhsCoefficients[i];
  131.         }
  132.         this.coefficients = new ArrayRealVector(sub, false);
  133.         this.relationship = relationship;
  134.         this.value        = rhsConstant - lhsConstant;
  135.     }

  137.     /**
  138.      * Build a constraint involving two linear equations.
  139.      * <p>
  140.      * A linear constraint with two linear equation has one of the forms:
  141.      * <ul>
  142.      *   <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> =
  143.      *       r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li>
  144.      *   <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> &lt;=
  145.      *       r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li>
  146.      *   <li>l<sub>1</sub>x<sub>1</sub> + ... l<sub>n</sub>x<sub>n</sub> + l<sub>cst</sub> >=
  147.      *       r<sub>1</sub>x<sub>1</sub> + ... r<sub>n</sub>x<sub>n</sub> + r<sub>cst</sub></li>
  148.      * </ul>
  149.      * </p>
  150.      * @param lhsCoefficients The coefficients of the linear expression on the left hand side of the constraint
  151.      * @param lhsConstant The constant term of the linear expression on the left hand side of the constraint
  152.      * @param relationship The type of (in)equality used in the constraint
  153.      * @param rhsCoefficients The coefficients of the linear expression on the right hand side of the constraint
  154.      * @param rhsConstant The constant term of the linear expression on the right hand side of the constraint
  155.      */
  156.     public LinearConstraint(final RealVector lhsCoefficients, final double lhsConstant,
  157.                             final Relationship relationship,
  158.                             final RealVector rhsCoefficients, final double rhsConstant) {
  159.         this.coefficients = lhsCoefficients.subtract(rhsCoefficients);
  160.         this.relationship = relationship;
  161.         this.value        = rhsConstant - lhsConstant;
  162.     }

  164.     /**
  165.      * Get the coefficients of the constraint (left hand side).
  166.      * @return coefficients of the constraint (left hand side)
  167.      */
  168.     public RealVector getCoefficients() {
  169.         return coefficients;
  170.     }

  172.     /**
  173.      * Get the relationship between left and right hand sides.
  174.      * @return relationship between left and right hand sides
  175.      */
  176.     public Relationship getRelationship() {
  177.         return relationship;
  178.     }

  180.     /**
  181.      * Get the value of the constraint (right hand side).
  182.      * @return value of the constraint (right hand side)
  183.      */
  184.     public double getValue() {
  185.         return value;
  186.     }

  188.     @Override
  189.     public boolean equals(Object other) {

  191.       if (this == other) {
  192.         return true;
  193.       }

  195.       if (other instanceof LinearConstraint) {
  196.           LinearConstraint rhs = (LinearConstraint) other;
  197.           return (relationship == rhs.relationship) &&
  198.                  (value        == rhs.value) &&
  199.                  coefficients.equals(rhs.coefficients);
  200.       }
  201.       return false;
  202.     }

  204.     @Override
  205.     public int hashCode() {
  206.         return relationship.hashCode() ^
  207.                Double.valueOf(value).hashCode() ^
  208.                coefficients.hashCode();
  209.     }

  211.     /**
  212.      * Serialize the instance.
  213.      * @param oos stream where object should be written
  214.      * @throws IOException if object cannot be written to stream
  215.      */
  216.     private void writeObject(ObjectOutputStream oos)
  217.         throws IOException {
  218.         oos.defaultWriteObject();
  219.         MatrixUtils.serializeRealVector(coefficients, oos);
  220.     }

  222.     /**
  223.      * Deserialize the instance.
  224.      * @param ois stream from which the object should be read
  225.      * @throws ClassNotFoundException if a class in the stream cannot be found
  226.      * @throws IOException if object cannot be read from the stream
  227.      */
  228.     private void readObject(ObjectInputStream ois)
  229.       throws ClassNotFoundException, IOException {
  230.         ois.defaultReadObject();
  231.         MatrixUtils.deserializeRealVector(this, "coefficients", ois);
  232.     }

  234. }
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