poi/src/main/java/org/apache/poi/ss/formula/functions/Sumxmy2.java

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   this work for additional information regarding copyright ownership.
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package org.apache.poi.ss.formula.functions;

/**
 * Implementation of Excel function SUMXMY2()<p>
 *
 * Calculates the sum of squares of differences between two arrays of the same size.<br>
 * <b>Syntax</b>:<br>
 * <b>SUMXMY2</b>(<b>arrayX</b>, <b>arrayY</b>)<p>
 *
 * result = &Sigma;<sub>i: 0..n</sub>(x<sub>i</sub>-y<sub>i</sub>)<sup>2</sup>
 */
public final class Sumxmy2 extends XYNumericFunction {

	private static final Accumulator XMinusYSquaredAccumulator = new Accumulator() {
		@Override
        public double accumulate(double x, double y) {
			double xmy = x - y;
			return xmy * xmy;
		}
	};

	@Override
	protected Accumulator createAccumulator() {
		return XMinusYSquaredAccumulator;
	}
}