/*
* 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.
*/

namespace HH.WMS.Utils.NPOI.SS.Formula.Functions
{

    /*
     * Implementation of Excel function SUMX2MY2()<p/>
     * 
     * Calculates the sum of differences of squares in two arrays of the same size.<br/>
     * <b>Syntax</b>:<br/>
     * <b>SUMX2MY2</b>(<b>arrayX</b>, <b>arrayY</b>)<p/>
     * 
     * result = &Sigma;<sub>i: 0..n</sub>(x<sub>i</sub><sup>2</sup>-y<sub>i</sub><sup>2</sup>)
     * 
     * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt; 
     */
    public class Sumx2my2 : XYNumericFunction
    {
        public class Accumulator2 : Accumulator
        {
            public double Accumulate(double x, double y)
            {
                return x * x - y * y;
            }
        }

        private static Accumulator XSquaredMinusYSquaredAccumulator = new Accumulator2();

        public override Accumulator CreateAccumulator()
        {
            return XSquaredMinusYSquaredAccumulator;
        }
    }
}