com.expleague.ml.loss.FBetaLogit Maven / Gradle / Ivy
package com.expleague.ml.loss;
import com.expleague.commons.math.vectors.Vec;
import com.expleague.ml.data.set.DataSet;
/**
* User: solar
* User: starlight
* Date: 10.09.13
* Time: 18:08
*/
public class FBetaLogit extends LLLogit {
private final PLogit precision;
private final RLogit recall;
private final double betta;
public FBetaLogit(final Vec target, final DataSet owner, final double betta) {
super(target, owner);
this.betta = betta;
this.precision = new PLogit(target, owner);
this.recall = new RLogit(target, owner);
}
/**
* @param point $y=-log(\frac{1}{p(x|c)} - 1)$ supposed to be there so that $p(x|c) = \frac{1}{1+e^{-x}}$
*/
@Override
public double value(final Vec point) {
final double precisionValue = precision.value(point);
final double recallValue = recall.value(point);
return (1 + betta * betta) * precisionValue * recallValue / (betta * betta * precisionValue + recallValue);
}
}