    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    }