com.expleague.ml.loss.SatL2 Maven / Gradle / Ivy
package com.expleague.ml.loss;
import com.expleague.commons.math.vectors.Vec;
import com.expleague.ml.data.set.DataSet;
/**
* User: solar
* Date: 21.12.2010
* Time: 22:37:55
*/
public class SatL2 extends L2 {
public SatL2(final Vec target, final DataSet base) {
super(target, base);
}
@Override
public double bestIncrement(final MSEStats stats) {
return stats.weight > 2 ? stats.sum/stats.weight : 0;
}
@Override
public double score(final 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;
}
}