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    package org.apache.commons.math3.stat.descriptive;
018    
019    import org.apache.commons.math3.exception.MathIllegalArgumentException;
020    import 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     */
028    public 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    }