KahanFunction.java

/**
 * (C) Copyright IBM Corp. 2010, 2015
 *
 * Licensed 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 com.ibm.bi.dml.runtime.functionobjects;

import com.ibm.bi.dml.runtime.instructions.cp.KahanObject;

import java.io.Serializable;


/**
 * Runtime function type to perform the summation of values using
 * the Kahan summation algorithm.
 */
public abstract class KahanFunction extends ValueFunction implements Serializable {

    private static final long serialVersionUID = -8880016655817461398L;

    /**
     * Add the given term to the existing sum with a function applied
     * using the Kahan summation algorithm.
     *
     * @param kObj A KahanObject containing the current sum and
     *             correction factor for the Kahan summation
     *             algorithm.
     * @param in The current term to be added.
     */
    public abstract void execute2(KahanObject kObj, double in);
}