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 */
017package org.apache.commons.math4.optim.linear;
018
019import org.apache.commons.math4.optim.OptimizationData;
020
021/**
022 * Pivot selection rule to the use for a Simplex solver.
023 *
024 * @since 3.3
025 */
026public enum PivotSelectionRule implements OptimizationData {
027    /**
028     * The classical rule, the variable with the most negative coefficient
029     * in the objective function row will be chosen as entering variable.
030     */
031    DANTZIG,
032    /**
033     * The first variable with a negative coefficient in the objective function
034     * row will be chosen as entering variable. This rule guarantees to prevent
035     * cycles, but may take longer to find an optimal solution.
036     */
037    BLAND
038}