org.apache.mahout.cf.taste.impl.common.RunningAverageAndStdDev.java Source code

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Here is the source code for org.apache.mahout.cf.taste.impl.common.RunningAverageAndStdDev.java

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/**
 * 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.mahout.cf.taste.impl.common;

/**
 * <p>
 * Extends {@link RunningAverage} by adding standard deviation too.
 * </p>
 */
public interface RunningAverageAndStdDev extends RunningAverage {

    /** @return standard deviation of data */
    double getStandardDeviation();

    /**
     * @return a (possibly immutable) object whose average is the negative of this object's
     */
    @Override
    RunningAverageAndStdDev inverse();

}