/*
* LensKit, an open source recommender systems toolkit.
* Copyright 2010-2014 LensKit Contributors. See CONTRIBUTORS.md.
* Work on LensKit has been funded by the National Science Foundation under
* grants IIS 05-34939, 08-08692, 08-12148, and 10-17697.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package org.grouplens.lenskit.slopeone;
import org.grouplens.lenskit.data.dao.*;
import org.grouplens.lenskit.data.event.Rating;
import org.grouplens.lenskit.data.event.Ratings;
import org.grouplens.lenskit.data.history.RatingVectorUserHistorySummarizer;
import org.grouplens.lenskit.data.history.UserHistorySummarizer;
import org.grouplens.lenskit.knn.item.model.ItemItemBuildContextProvider;
import org.grouplens.lenskit.transform.normalize.DefaultUserVectorNormalizer;
import org.junit.Test;
import java.util.ArrayList;
import java.util.List;
import static org.junit.Assert.assertEquals;
public class SlopeOneModelBuilderTest {
public static final double EPSILON = 1.0e-6;
private SlopeOneModel getModel(List<Rating> ratings) {
EventDAO dao = EventCollectionDAO.create(ratings);
UserEventDAO udao = new PrefetchingUserEventDAO(dao);
ItemDAO idao = new PrefetchingItemDAO(dao);
UserHistorySummarizer summarizer = new RatingVectorUserHistorySummarizer();
ItemItemBuildContextProvider contextFactory = new ItemItemBuildContextProvider(
udao, new DefaultUserVectorNormalizer(), summarizer);
SlopeOneModelBuilder provider = new SlopeOneModelBuilder(idao, contextFactory.get(), 0);
return provider.get();
}
@Test
public void testBuild1() {
List<Rating> rs = new ArrayList<Rating>();
rs.add(Ratings.make(1, 5, 2));
rs.add(Ratings.make(2, 5, 4));
rs.add(Ratings.make(1, 3, 5));
rs.add(Ratings.make(2, 3, 4));
SlopeOneModel model1 = getModel(rs);
assertEquals(2, model1.getCoratings(5, 3));
assertEquals(2, model1.getCoratings(3, 5));
assertEquals(-1.5, model1.getDeviation(5, 3), EPSILON);
assertEquals(1.5, model1.getDeviation(3, 5), EPSILON);
}
@Test
public void testBuild2() {
List<Rating> rs = new ArrayList<Rating>();
rs.add(Ratings.make(1, 4, 4));
rs.add(Ratings.make(2, 4, 5));
rs.add(Ratings.make(3, 4, 4));
rs.add(Ratings.make(1, 5, 3));
rs.add(Ratings.make(2, 5, 5));
rs.add(Ratings.make(3, 5, 1));
rs.add(Ratings.make(1, 6, 1));
rs.add(Ratings.make(2, 6, 5));
rs.add(Ratings.make(3, 6, 3));
SlopeOneModel model2 = getModel(rs);
assertEquals(3, model2.getCoratings(4, 5));
assertEquals(3, model2.getCoratings(5, 4));
assertEquals(3, model2.getCoratings(4, 6));
assertEquals(3, model2.getCoratings(6, 4));
assertEquals(3, model2.getCoratings(5, 6));
assertEquals(3, model2.getCoratings(6, 5));
assertEquals(4 / 3.0, model2.getDeviation(4, 6), EPSILON);
assertEquals(-4 / 3.0, model2.getDeviation(6, 4), EPSILON);
assertEquals(4 / 3.0, model2.getDeviation(4, 5), EPSILON);
assertEquals(-4 / 3.0, model2.getDeviation(5, 4), EPSILON);
assertEquals(0, model2.getDeviation(5, 6), EPSILON);
assertEquals(0, model2.getDeviation(6, 5), EPSILON);
}
@Test
public void testBuild3() {
List<Rating> rs = new ArrayList<Rating>();
rs.add(Ratings.make(1, 6, 4));
rs.add(Ratings.make(2, 6, 2));
rs.add(Ratings.make(1, 7, 3));
rs.add(Ratings.make(2, 7, 2));
rs.add(Ratings.make(3, 7, 5));
rs.add(Ratings.make(4, 7, 2));
rs.add(Ratings.make(1, 8, 3));
rs.add(Ratings.make(2, 8, 4));
rs.add(Ratings.make(3, 8, 3));
rs.add(Ratings.make(4, 8, 2));
rs.add(Ratings.make(5, 8, 3));
rs.add(Ratings.make(6, 8, 2));
rs.add(Ratings.make(1, 9, 3));
rs.add(Ratings.make(3, 9, 4));
SlopeOneModel model3 = getModel(rs);
assertEquals(2, model3.getCoratings(6, 7));
assertEquals(2, model3.getCoratings(7, 6));
assertEquals(2, model3.getCoratings(6, 8));
assertEquals(2, model3.getCoratings(8, 6));
assertEquals(1, model3.getCoratings(6, 9));
assertEquals(1, model3.getCoratings(9, 6));
assertEquals(4, model3.getCoratings(7, 8));
assertEquals(4, model3.getCoratings(8, 7));
assertEquals(2, model3.getCoratings(7, 9));
assertEquals(2, model3.getCoratings(9, 7));
assertEquals(2, model3.getCoratings(8, 9));
assertEquals(2, model3.getCoratings(9, 8));
assertEquals(0.5, model3.getDeviation(6, 7), EPSILON);
assertEquals(-0.5, model3.getDeviation(7, 6), EPSILON);
assertEquals(-0.5, model3.getDeviation(6, 8), EPSILON);
assertEquals(0.5, model3.getDeviation(8, 6), EPSILON);
assertEquals(1, model3.getDeviation(6, 9), EPSILON);
assertEquals(-1, model3.getDeviation(9, 6), EPSILON);
assertEquals(0, model3.getDeviation(7, 8), EPSILON);
assertEquals(0, model3.getDeviation(8, 7), EPSILON);
assertEquals(0.5, model3.getDeviation(7, 9), EPSILON);
assertEquals(-0.5, model3.getDeviation(9, 7), EPSILON);
assertEquals(-0.5, model3.getDeviation(8, 9), EPSILON);
assertEquals(0.5, model3.getDeviation(9, 8), EPSILON);
}
@Test
public void testBuild4() {
List<Rating> rs = new ArrayList<Rating>();
rs.add(Ratings.make(1, 4, 3.5));
rs.add(Ratings.make(2, 4, 5));
rs.add(Ratings.make(3, 5, 4.25));
rs.add(Ratings.make(2, 6, 3));
rs.add(Ratings.make(1, 7, 4));
rs.add(Ratings.make(2, 7, 4));
rs.add(Ratings.make(3, 7, 1.5));
SlopeOneModel model4 = getModel(rs);
assertEquals(0, model4.getCoratings(4, 5));
assertEquals(0, model4.getCoratings(5, 4));
assertEquals(1, model4.getCoratings(4, 6));
assertEquals(1, model4.getCoratings(6, 4));
assertEquals(2, model4.getCoratings(4, 7));
assertEquals(2, model4.getCoratings(7, 4));
assertEquals(0, model4.getCoratings(5, 6));
assertEquals(0, model4.getCoratings(6, 5));
assertEquals(1, model4.getCoratings(5, 7));
assertEquals(1, model4.getCoratings(7, 5));
assertEquals(1, model4.getCoratings(6, 7));
assertEquals(1, model4.getCoratings(7, 6));
assertEquals(Double.NaN, model4.getDeviation(4, 5), 0);
assertEquals(Double.NaN, model4.getDeviation(5, 4), 0);
assertEquals(2, model4.getDeviation(4, 6), EPSILON);
assertEquals(-2, model4.getDeviation(6, 4), EPSILON);
assertEquals(0.25, model4.getDeviation(4, 7), EPSILON);
assertEquals(-0.25, model4.getDeviation(7, 4), EPSILON);
assertEquals(Double.NaN, model4.getDeviation(5, 6), 0);
assertEquals(Double.NaN, model4.getDeviation(6, 5), 0);
assertEquals(2.75, model4.getDeviation(5, 7), EPSILON);
assertEquals(-2.75, model4.getDeviation(7, 5), EPSILON);
assertEquals(-1, model4.getDeviation(6, 7), EPSILON);
assertEquals(1, model4.getDeviation(7, 6), EPSILON);
}
}