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.math3.stat.descriptive;
018
019import org.apache.commons.math3.exception.MathIllegalArgumentException;
020import org.apache.commons.math3.util.MathArrays;
021
022
023/**
024 * Base interface implemented by all statistics.
025 *
026 * @version $Id: UnivariateStatistic.java 1416643 2012-12-03 19:37:14Z tn $
027 */
028public interface UnivariateStatistic extends MathArrays.Function {
029    /**
030     * Returns the result of evaluating the statistic over the input array.
031     *
032     * @param values input array
033     * @return the value of the statistic applied to the input array
034     * @throws MathIllegalArgumentException  if values is null
035     */
036    double evaluate(double[] values) throws MathIllegalArgumentException;
037
038    /**
039     * Returns the result of evaluating the statistic over the specified entries
040     * in the input array.
041     *
042     * @param values the input array
043     * @param begin the index of the first element to include
044     * @param length the number of elements to include
045     * @return the value of the statistic applied to the included array entries
046     * @throws MathIllegalArgumentException if values is null or the indices are invalid
047     */
048    double evaluate(double[] values, int begin, int length) throws MathIllegalArgumentException;
049
050    /**
051     * Returns a copy of the statistic with the same internal state.
052     *
053     * @return a copy of the statistic
054     */
055    UnivariateStatistic copy();
056}