com.expleague.ml.loss.blockwise.BlockwiseSatL2 Maven / Gradle / Ivy
package com.expleague.ml.loss.blockwise;
import com.expleague.commons.math.vectors.Vec;
import com.expleague.ml.data.set.DataSet;
/**
* User: qdeee
* Date: 21.07.14
*/
public class BlockwiseSatL2 extends BlockwiseL2 {
public BlockwiseSatL2(final Vec target, final DataSet owner) {
super(target, owner);
}
@Override
public double bestIncrement(final BlockwiseL2.MSEStats stats) {
return stats.weight > 2 ? stats.sum/stats.weight : 0;
}
@Override
public double score(final BlockwiseL2.MSEStats stats) {
final double n = stats.weight;
return n > 2 ? n*(n-2)/(n * n - 3 * n + 1) * (stats.sum2 - stats.sum * stats.sum / n) : stats.sum2;
}
}