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means

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This commit is contained in:
Michael Zhang 2021-09-06 16:03:42 -05:00
parent ac61899f6e
commit 609785d503
Signed by: michael
GPG key ID: BDA47A31A3C8EE6B
3 changed files with 49 additions and 6 deletions
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3
nonpers-assignment/.gitignore vendored
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@ -1 +1,4 @@
.gradle
.project
.settings
build

33
nonpers-assignment/src/main/java/org/lenskit/mooc/nonpers/mean/DampedItemMeanModelProvider.java
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@ -2,6 +2,7 @@ package org.lenskit.mooc.nonpers.mean;
import it.unimi.dsi.fastutil.longs.Long2DoubleOpenHashMap;
import it.unimi.dsi.fastutil.longs.Long2IntOpenHashMap;
import it.unimi.dsi.fastutil.longs.LongSet;
import org.lenskit.baseline.MeanDamping;
import org.lenskit.data.dao.DataAccessObject;
import org.lenskit.data.ratings.Rating;
@ -62,7 +63,35 @@ public class DampedItemMeanModelProvider implements Provider<ItemMeanModel> {
@Override
public ItemMeanModel get() {
// TODO Compute damped means
// TODO Remove the line below when you have finished
throw new UnsupportedOperationException("damped mean not implemented");
Long2DoubleOpenHashMap means = new Long2DoubleOpenHashMap();
Long2IntOpenHashMap lens = new Long2IntOpenHashMap();
double globalMean = 0;
int globalLen = 0;
try (ObjectStream<Rating> ratings = dao.query(Rating.class).stream()) {
for (Rating r: ratings) {
// this loop will run once for each rating in the data set
means.addTo(r.getItemId(), r.getValue());
lens.addTo(r.getItemId(), 1);
globalMean += r.getValue();
globalLen += 1;
}
}
globalMean /= globalLen;
LongSet keys = means.keySet();
for (long key : keys) {
double val = means.get(key);
val = (val + damping * globalMean) / (lens.get(key) + damping);
means.put(key, val);
if (key == 2959 || key == 1203) {
logger.info("Damped mean for item {} is {}", key, val);
}
}
return new ItemMeanModel(means);
}
}

19
nonpers-assignment/src/main/java/org/lenskit/mooc/nonpers/mean/ItemMeanModelProvider.java
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@ -2,6 +2,7 @@ package org.lenskit.mooc.nonpers.mean;
import it.unimi.dsi.fastutil.longs.Long2DoubleOpenHashMap;
import it.unimi.dsi.fastutil.longs.Long2IntOpenHashMap;
import it.unimi.dsi.fastutil.longs.LongSet;
import org.lenskit.data.dao.DataAccessObject;
import org.lenskit.data.ratings.Rating;
import org.lenskit.inject.Transient;
@ -51,17 +52,27 @@ public class ItemMeanModelProvider implements Provider<ItemMeanModel> {
*/
@Override
public ItemMeanModel get() {
// TODO Set up data structures for computing means
Long2DoubleOpenHashMap means = new Long2DoubleOpenHashMap();
Long2IntOpenHashMap lens = new Long2IntOpenHashMap();
try (ObjectStream<Rating> ratings = dao.query(Rating.class).stream()) {
for (Rating r: ratings) {
// this loop will run once for each rating in the data set
// TODO process this rating
means.addTo(r.getItemId(), r.getValue());
lens.addTo(r.getItemId(), 1);
}
}
Long2DoubleOpenHashMap means = new Long2DoubleOpenHashMap();
// TODO Finalize means to store them in the mean model
LongSet keys = means.keySet();
for (long key : keys) {
double val = means.get(key);
val /= lens.get(key);
means.put(key, val);
if (key == 2959 || key == 1203) {
logger.info("Damped mean for item {} is {}", key, val);
}
}
logger.info("computed mean ratings for {} items", means.size());
return new ItemMeanModel(means);