package classification;
import types.Evaluation;
/***
* This class implements a loss function for high precision or recall.
*
* @author Kuzman Ganchev and Georgi Georgiev <A
* HREF="mailto:georgiev@ontotext.com>georgi.georgiev@ontotext.com</A>
* <A HREF="mailto:ganchev@ontotext.com>kuzman.ganchev@ontotext.com</A>
* Date: Thu Feb 26 12:27:56 EET 2009
*/
public class PrecRecLoss implements Loss {
int tagOfInterest;
double precWeight;
double recWeight;
public PrecRecLoss(int tagOfInterest, double precWeight) {
this.tagOfInterest = tagOfInterest;
if (Double.isInfinite(precWeight)) {
recWeight = 0;
this.precWeight = 1;
} else {
recWeight = 1;
this.precWeight = precWeight;
}
}
public double calculate(int truth, int guess) {
Evaluation eval = Evaluate.eval(truth, guess, tagOfInterest);
// this ensures that we don't make an update if fn = 0.
if (precWeight == 0 && eval.fn == 0)
return -1e10;
return eval.fp * precWeight + eval.fn * recWeight;
}
}