public IReadOnlyList <WeightedMovie> GetRecoMovies(User u, UserRecoOptions options)
{
var users = GetSimilarUsers(u, options.NbSimilarUser, options.OnlyPositiveUserSimilarity);
var allMovies = new Dictionary <Movie, WeightedMovie>();
foreach (var other in users)
{
foreach (var movieRated in other.User.Ratings)
{
var m = movieRated.Key;
if (u.Ratings.ContainsKey(m))
{
continue;
}
allMovies.TryGetValue(m, out WeightedMovie already);
double deltaWeight = other.Similarity
* (movieRated.Value - options.DeltaMovieRating);
allMovies[m] = new WeightedMovie(
m,
already.TotalWeight + deltaWeight,
already.Count + 1);
}
}
var bestMovies = new BestKeeper <WeightedMovie>(
options.MaxMovieCount,
(m1, m2) => Math.Sign(m2.Weight - m1.Weight));
foreach (var mW in allMovies.Values)
{
bestMovies.Add(mW);
}
return(bestMovies);
}
public IReadOnlyCollection <SimilarMovies> GetSimilarMovies(Movie m, User[] users, int count = 100)
{
BestKeeper <SimilarMovies> best = new BestKeeper <SimilarMovies>(count,
(m1, m2) => Math.Sign(m1.Similarity - m2.Similarity));
foreach (var movie in Movies)
{
if (movie != m)
{
best.AddCandidate(new SimilarMovies(movie, SimilarityPearson(m, movie, users)));
}
}
return(best);
}
public IReadOnlyCollection <SimilarUser> GetSimilarUsers(User u, int count = 100)
{
BestKeeper <SimilarUser> best = new BestKeeper <SimilarUser>(count,
(u1, u2) => Math.Sign(u1.Similarity - u2.Similarity));
foreach (var other in Users)
{
if (other != u)
{
best.AddCandidate(new SimilarUser(other, SimilarityPearson(u, other)));
}
}
return(best);
}
public SimilarMovie[] GetSimilarMovies(Movie m, int count)
{
BestKeeper <SimilarMovie> best = new BestKeeper <SimilarMovie>(count,
(s1, s2) => Math.Sign(s2.Similarity - s1.Similarity));
foreach (var other in Movies)
{
if (other == m)
{
continue;
}
SimilarMovie sM = new SimilarMovie(other, SimilarityPearson(m, other));
best.Add(sM);
}
return(best.ToArray());
}
public SimilarUser[] GetSimilarUsers(User u, int count)
{
BestKeeper <SimilarUser> best = new BestKeeper <SimilarUser>(count,
(s1, s2) => Math.Sign(s2.Similarity - s1.Similarity));
//BestKeeper<SimilarUser> worst = new BestKeeper<SimilarUser>( count,
// (s1,s2) => Math.Sign( s1.Similarity - s2.Similarity ) );
foreach (var other in Users)
{
if (other == u)
{
continue;
}
SimilarUser sU = new SimilarUser(other, SimilarityPearson(u, other));
best.Add(sU);
}
return(best.ToArray());
}