Check-in commons-math 3.6.1

This includes many changes over the original version and is
also incompatible, which is why the existing commons-math library
is left untouched.

Test: N/A
Change-Id: Icd0f3069a3c62b2572f2263732d91e6c3b6e8cba

1 files changed, 38 insertions, 0 deletions

diff --git a/src/main/java/org/apache/commons/math3/optim/linear/PivotSelectionRule.java b/src/main/java/org/apache/commons/math3/optim/linear/PivotSelectionRule.java
new file mode 100644
index 0000000..a2a2765
--- /dev/null
+++ b/src/main/java/org/apache/commons/math3/optim/linear/PivotSelectionRule.java
@@ -0,0 +1,38 @@
+/*
+ * 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.math3.optim.linear;
+
+import org.apache.commons.math3.optim.OptimizationData;
+
+/**
+ * Pivot selection rule to the use for a Simplex solver.
+ *
+ * @since 3.3
+ */
+public enum PivotSelectionRule implements OptimizationData {
+    /**
+     * The classical rule, the variable with the most negative coefficient
+     * in the objective function row will be chosen as entering variable.
+     */
+    DANTZIG,
+    /**
+     * The first variable with a negative coefficient in the objective function
+     * row will be chosen as entering variable. This rule guarantees to prevent
+     * cycles, but may take longer to find an optimal solution.
+     */
+    BLAND
+}