public List <UsersSimilarity> CreateUserSimilarities(ISettings settings,
int userId,
List <int> comparedUserId,
BookScore[] userBooks,
List <BookScore[]> comparedUserBooks,
List <double?> similarity = null)
{
var userSimilarities = new List <UsersSimilarity>();
var comparer = new BookScoreEqualityComparer();
for (int i = 0; i < comparedUserId.Count; i++)
{
var comparedUserRatesForMutualBooks = comparedUserBooks[i].Intersect(userBooks, comparer).ToArray();
var userRatesForMutualBooks = userBooks.Intersect(comparedUserBooks[i], comparer).ToArray();
var booksUniqueForComparedUser = comparedUserBooks[i].Except(userBooks, comparer).ToArray();
var temp = new UsersSimilarity
{
AverageScoreForComparedUser = RandomNumber(3),
ComparedUserId = comparedUserId[i],
UserId = userId,
Similarity = similarity?[i],
SimilarityType = (int)settings.SimilarityDistance,
ComparedUserRatesForMutualBooks = comparedUserRatesForMutualBooks,
BooksUniqueForComparedUser = booksUniqueForComparedUser,
UserRatesForMutualBooks = userRatesForMutualBooks
};
userSimilarities.Add(temp);
}
return(userSimilarities);
}
public void GetNearestNeighbors_WhenSimilarityIsNotNull_ShouldNotReturnNull()
{
var similarity = new UsersSimilarity
{
ComparedUserRatesForMutualBooks = _helpers.CreateBookScores(2, new[] { "1", "2", "3" }, new short[] { 1, 2, 3 }),
UserRatesForMutualBooks = _helpers.CreateBookScores(2, new[] { "1", "2", "3" }, new short[] { 1, 2, 3 }),
};
_usersSelector.SelectMutualAndUniqueBooksForUsers(1, 2).Returns(similarity);
var actual = _sut.GetNearestNeighbors(1, new List <int>()
{
2
}, _settings);
actual.ShouldNotBeNull();
}
public void testAddDuplicateValues()
{
UsersSimilarity usersSimilarity = new UsersSimilarity(2);
usersSimilarity.add(new User("first"), 1.1);
usersSimilarity.add(new User("second"), 1.1);
List <KeyValuePair <User, double> > expected = new List <KeyValuePair <User, double> >()
{
new KeyValuePair <User, double>(new User("first"), 1.1),
new KeyValuePair <User, double>(new User("second"), 1.1)
};
List <KeyValuePair <User, double> > actual = usersSimilarity.AsList();
CollectionAssert.AreEqual(expected, actual);
}
public void GetNearestNeighbors_WhenBooksAreTheSAme_ShouldReturnMaxSimilarity(DistanceSimilarityEnum distance)
{
_settings.SimilarityDistance = distance;
var similarity = new UsersSimilarity
{
ComparedUserRatesForMutualBooks = _helpers.CreateBookScores(2, new[] { "1", "2", "3" }, new short[] { 1, 2, 3 }),
UserRatesForMutualBooks = _helpers.CreateBookScores(2, new[] { "1", "2", "3" }, new short[] { 1, 2, 3 }),
};
_usersSelector.SelectMutualAndUniqueBooksForUsers(1, 2).Returns(similarity);
var actual = _sut.GetNearestNeighbors(1, new List <int>()
{
2
}, _settings).FirstOrDefault();
actual.ShouldNotBeNull();
actual.Similarity.Value.ShouldBe(1, 2);
}
public void Compare_ShouldReturnLower(int userId, int comparedUserId, int mutualBooksLenth, double similarity)
{
var x = new UsersSimilarity
{
UserId = userId,
ComparedUserId = comparedUserId,
ComparedUserRatesForMutualBooks = new BookScore[mutualBooksLenth],
Similarity = similarity
};
var y = new UsersSimilarity
{
UserId = 1,
ComparedUserId = 2,
ComparedUserRatesForMutualBooks = new BookScore[10],
Similarity = 1.2
};
_sut.Compare(x, y).ShouldBe(1);
}
public void GetNearestNeighbors_ShouldReturnTwoMostSimilarUsers(DistanceSimilarityEnum distance)
{
_settings.SimilarityDistance = distance;
var similarity_1 = new UsersSimilarity
{
ComparedUserRatesForMutualBooks = _helpers.CreateBookScores(2, new[] { "1", "2", "3" }, new short[] { 1, 2, 2 }),
UserRatesForMutualBooks = _helpers.CreateBookScores(1, new[] { "1", "2", "3" }, new short[] { 1, 2, 2 }),
ComparedUserId = 2
};
var similarity_2 = new UsersSimilarity
{
ComparedUserRatesForMutualBooks = _helpers.CreateBookScores(3, new[] { "1", "2", "3" }, new short[] { 1, 2, 2 }),
UserRatesForMutualBooks = _helpers.CreateBookScores(1, new[] { "1", "2", "3" }, new short[] { 1, 4, 2 }),
ComparedUserId = 3
};
var similarity_3 = new UsersSimilarity
{
ComparedUserRatesForMutualBooks = _helpers.CreateBookScores(4, new[] { "1", "2", "3" }, new short[] { 1, 2, 2 }),
UserRatesForMutualBooks = _helpers.CreateBookScores(1, new[] { "1", "2", "3" }, new short[] { 10, 5, 3 }),
ComparedUserId = 4
};
_usersSelector.SelectMutualAndUniqueBooksForUsers(1, 2).Returns(similarity_1);
_usersSelector.SelectMutualAndUniqueBooksForUsers(1, 3).Returns(similarity_2);
_usersSelector.SelectMutualAndUniqueBooksForUsers(1, 4).Returns(similarity_3);
var actual = _sut.GetNearestNeighbors(1, new List <int>()
{
2, 3, 4
}, _settings);
actual.ShouldNotBeNull();
actual.Select(x => x.ComparedUserId).ShouldBe(new[] { 2, 3 });
actual.Count.ShouldBe(2);
}
