/**
* Get the probability distribution according to score and thresholds
*
* @param score The score
* @param vec The MutableVec to be filled in.
*/
public void getProbDistribution(double score, Vector vec) {
double pre = getProbLE(score, 0);
vec.set(0, pre);
for (int i = 1; i < getLevelCount(); i++) {
double pro = getProbLE(score, i);
vec.set(i, pro - pre);
pre = pro;
}
}
/** The train function of OrdRec. Get all parameters after learning process. */
@SuppressWarnings("ConstantConditions")
private void train(SparseVector ratings, MutableSparseVector scores) {
Vector dbeta = Vector.createLength(beta.length());
double dt1;
// n is the number of iteration;
for (int j = 0; j < iterationCount; j++) {
for (VectorEntry rating : ratings.fast()) {
long iid = rating.getKey();
double score = scores.get(iid);
int r = quantizer.index(rating.getValue());
double probEqualR = getProbEQ(score, r);
double probLessR = getProbLE(score, r);
double probLessR_1 = getProbLE(score, r - 1);
dt1 =
learningRate
/ probEqualR
* (probLessR * (1 - probLessR) * derivateOfBeta(r, 0, t1)
- probLessR_1 * (1 - probLessR_1) * derivateOfBeta(r - 1, 0, t1)
- regTerm * t1);
double dbetaK;
for (int k = 0; k < beta.length(); k++) {
dbetaK =
learningRate
/ probEqualR
* (probLessR * (1 - probLessR) * derivateOfBeta(r, k + 1, beta.get(k))
- probLessR_1
* (1 - probLessR_1)
* derivateOfBeta(r - 1, k + 1, beta.get(k))
- regTerm * beta.get(k));
dbeta.set(k, dbetaK);
}
t1 = t1 + dt1;
beta.add(dbeta);
}
}
}