/**
* @param id ID to hash
* @param numericID explicit, supplied hash of {@code id} argument, given to be stored in the
* mapping
*/
public void addMapping(String id, long numericID) {
Lock writeLock = lock.writeLock();
writeLock.lock();
try {
reverseMapping.put(numericID, id);
} finally {
writeLock.unlock();
}
}
@Test
public void testLSH() {
RandomGenerator random = RandomManager.getRandom();
Mean avgPercentTopRecsConsidered = new Mean();
Mean avgNDCG = new Mean();
Mean avgPercentAllItemsConsidered = new Mean();
for (int iteration = 0; iteration < ITERATIONS; iteration++) {
LongObjectMap<float[]> Y = new LongObjectMap<float[]>();
for (int i = 0; i < NUM_ITEMS; i++) {
Y.put(i, RandomUtils.randomUnitVector(NUM_FEATURES, random));
}
float[] userVec = RandomUtils.randomUnitVector(NUM_FEATURES, random);
double[] results = doTestRandomVecs(Y, userVec);
double percentTopRecsConsidered = results[0];
double ndcg = results[1];
double percentAllItemsConsidered = results[2];
log.info(
"Considered {}% of all candidates, {} nDCG, got {}% recommendations correct",
100 * percentAllItemsConsidered, ndcg, 100 * percentTopRecsConsidered);
avgPercentTopRecsConsidered.increment(percentTopRecsConsidered);
avgNDCG.increment(ndcg);
avgPercentAllItemsConsidered.increment(percentAllItemsConsidered);
}
log.info("{}", avgPercentTopRecsConsidered.getResult());
log.info("{}", avgNDCG.getResult());
log.info("{}", avgPercentAllItemsConsidered.getResult());
assertTrue(avgPercentTopRecsConsidered.getResult() > 0.8);
assertTrue(avgNDCG.getResult() > 0.8);
assertTrue(avgPercentAllItemsConsidered.getResult() < 0.09);
}