public void addFeature(String label, String feature) {
if (!featureMap.containsKey(new FeatureKey(label, feature))) {
featureMap.put(new FeatureKey(label, feature), new FeatureValue());
} else {
this.updateCount(label, feature);
}
if (!featureCount.containsKey(feature)) {
featureCount.put(feature, 1);
} else {
featureCount.put(feature, featureCount.get(feature) + 1);
}
}
// calculate p(y|x)=sum_i(alpha_i*f_i(x,y))/sum_y(sum_i(alpha_i*f_i(x,y))).
public Map<String, Double> predict(List<String> x) {
Map<String, Double> probMap = new HashMap<String, Double>();
double sum = 0;
for (String label : labelSet) {
double prob = 0;
for (String feature : x) {
prob += features.getModelWeight(label, feature);
}
prob = Math.exp(prob);
probMap.put(label, prob);
sum += prob;
}
for (String label : probMap.keySet()) {
probMap.put(label, probMap.get(label) / sum);
}
return probMap;
}