| /* |
| * 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.math4.legacy.optim.linear; |
| |
| import org.apache.commons.math4.legacy.linear.ArrayRealVector; |
| import org.apache.commons.math4.legacy.linear.RealVector; |
| |
| /** |
| * 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. |
| * |
| * @since 2.0 |
| */ |
| public class LinearConstraint { |
| /** Coefficients of the constraint (left hand side). */ |
| private final transient RealVector coefficients; |
| /** Relationship between left and right hand sides {@code (=, <=, >=)}. */ |
| 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> |
| * |
| * @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> |
| * |
| * @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> |
| * |
| * @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> |
| * |
| * @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; |
| } |
| |
| /** {@inheritDoc} */ |
| @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; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public int hashCode() { |
| return relationship.hashCode() ^ |
| Double.valueOf(value).hashCode() ^ |
| coefficients.hashCode(); |
| } |
| } |
