001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.math.optimization.linear; 019 020 /** 021 * Types of relationships between two cells in a Solver {@link LinearConstraint}. 022 * @version $Revision: 758920 $ $Date: 2009-03-26 19:25:30 -0400 (Thu, 26 Mar 2009) $ 023 * @since 2.0 024 */ 025 public enum Relationship { 026 027 /** Equality relationship. */ 028 EQ("="), 029 030 /** Lesser than or equal relationship. */ 031 LEQ("<="), 032 033 /** Greater than or equal relationship. */ 034 GEQ(">="); 035 036 /** Display string for the relationship. */ 037 private String stringValue; 038 039 /** Simple constructor. 040 * @param stringValue display string for the relationship 041 */ 042 private Relationship(String stringValue) { 043 this.stringValue = stringValue; 044 } 045 046 /** {@inheritDoc} */ 047 @Override 048 public String toString() { 049 return stringValue; 050 } 051 052 /** 053 * Get the relationship obtained when multiplying all coefficients by -1. 054 * @return relationship obtained when multiplying all coefficients by -1 055 */ 056 public Relationship oppositeRelationship() { 057 switch (this) { 058 case LEQ : 059 return GEQ; 060 case GEQ : 061 return LEQ; 062 default : 063 return EQ; 064 } 065 } 066 067 }