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 package org.apache.commons.math4.legacy.optim.linear;
18
19 /**
20 * Types of relationships between two cells in a Solver {@link LinearConstraint}.
21 *
22 * @since 2.0
23 */
24 public enum Relationship {
25 /** Equality relationship. */
26 EQ("="),
27 /** Lesser than or equal relationship. */
28 LEQ("<="),
29 /** Greater than or equal relationship. */
30 GEQ(">=");
31
32 /** Display string for the relationship. */
33 private final String stringValue;
34
35 /**
36 * Simple constructor.
37 *
38 * @param stringValue Display string for the relationship.
39 */
40 Relationship(String stringValue) {
41 this.stringValue = stringValue;
42 }
43
44 /** {@inheritDoc} */
45 @Override
46 public String toString() {
47 return stringValue;
48 }
49
50 /**
51 * Gets the relationship obtained when multiplying all coefficients by -1.
52 *
53 * @return the opposite relationship.
54 */
55 public Relationship oppositeRelationship() {
56 switch (this) {
57 case LEQ :
58 return GEQ;
59 case GEQ :
60 return LEQ;
61 default :
62 return EQ;
63 }
64 }
65 }