/*
 * #%L
 * Image processing operations for SciJava Ops.
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package org.scijava.ops.image.stats;

import net.imglib2.type.numeric.RealType;

import org.scijava.function.Computers;
import org.scijava.ops.spi.Op;
import org.scijava.ops.spi.OpDependency;

/**
 * Op to calculate the {@code stats.moment4AboutMean} using {@code stats.mean}
 * and {@code stats.size}.
 *
 * @author Daniel Seebacher (University of Konstanz)
 * @author Christian Dietz (University of Konstanz)
 * @param <I> input type
 * @param <O> output type
 * @implNote op names='stats.moment4AboutMean'
 */
public class IterableMoment4AboutMean<I extends RealType<I>, O extends RealType<O>>
	implements Computers.Arity1<Iterable<I>, O>
{

	@OpDependency(name = "stats.mean")
	private Computers.Arity1<Iterable<I>, O> meanComputer;
	@OpDependency(name = "stats.size")
	private Computers.Arity1<Iterable<I>, O> sizeComputer;

	/**
	 * TODO
	 *
	 * @param input
	 * @param moment4AboutMean
	 */
	@Override
	public void compute(final Iterable<I> input, final O moment4AboutMean) {

		final var mean = moment4AboutMean.createVariable();
		meanComputer.compute(input, mean);
		final var size = moment4AboutMean.createVariable();
		sizeComputer.compute(input, size);

		double res = 0;
		final var m = mean.getRealDouble();
		for (final var in : input) {
			final var val = in.getRealDouble() - m;
			res += val * val * val * val;
		}

		moment4AboutMean.setReal(res / size.getRealDouble());
	}
}
