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 */
17
18package org.apache.commons.math.optimization.linear;
19
20/**
21 * Types of relationships between two cells in a Solver {@link LinearConstraint}.
22 * @version $Revision: 1003886 $ $Date: 2010-10-02 23:04:44 +0200 (sam. 02 oct. 2010) $
23 * @since 2.0
24 */
25public enum Relationship {
26
27    /** Equality relationship. */
28    EQ("="),
29
30    /** Lesser than or equal relationship. */
31    LEQ("<="),
32
33    /** Greater than or equal relationship. */
34    GEQ(">=");
35
36    /** Display string for the relationship. */
37    private final String stringValue;
38
39    /** Simple constructor.
40     * @param stringValue display string for the relationship
41     */
42    private Relationship(String stringValue) {
43        this.stringValue = stringValue;
44    }
45
46    /** {@inheritDoc} */
47    @Override
48    public String toString() {
49        return stringValue;
50    }
51
52    /**
53     * Get the relationship obtained when multiplying all coefficients by -1.
54     * @return relationship obtained when multiplying all coefficients by -1
55     */
56    public Relationship oppositeRelationship() {
57        switch (this) {
58        case LEQ :
59            return GEQ;
60        case GEQ :
61            return LEQ;
62        default :
63            return EQ;
64        }
65    }
66
67}
68