| /* |
| * 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.math4.util; |
| |
| import org.apache.commons.math4.exception.MathIllegalArgumentException; |
| |
| |
| /** |
| * A strategy to pick a pivoting index of an array for doing partitioning. |
| * @see MedianOf3PivotingStrategy |
| * @see RandomPivotingStrategy |
| * @see CentralPivotingStrategy |
| * @since 3.4 |
| */ |
| public interface PivotingStrategyInterface { |
| |
| /** |
| * Find pivot index of the array so that partition and K<sup>th</sup> |
| * element selection can be made |
| * @param work data array |
| * @param begin index of the first element of the slice |
| * @param end index after the last element of the slice |
| * @return the index of the pivot element chosen between the |
| * first and the last element of the array slice |
| * @throws MathIllegalArgumentException when indices exceeds range |
| */ |
| int pivotIndex(double[] work, int begin, int end) |
| throws MathIllegalArgumentException; |
| |
| } |