public static RecommenderResult RecommendUser(
this IMatrixFactorizationRecommender recommender,
UserFeatures user)
{
if (recommender == null)
{
throw new ArgumentNullException(nameof(recommender));
}
if (user == null)
{
throw new ArgumentNullException(nameof(user));
}
return(recommender.RecommendUser(user, RecommenderResultBuilderFactory.Instance));
}
public UserFeatures?GetUserFeatures(string userId)
{
if (userId == null)
{
throw new ArgumentNullException(nameof(userId));
}
if (!this.userMap.ContainsKey(userId))
{
return(null);
}
var xu = this.userFactors.Row(this.userMap[userId]);
var user = new UserFeatures(xu);
return(user);
}
public TResult RecommendUser <TResult>(string userId, IResultBuilderFactory <TResult> resultBuilderFactory)
{
if (userId == null)
{
throw new ArgumentNullException(nameof(userId));
}
if (!this.userMap.ContainsKey(userId))
{
return(resultBuilderFactory.CreateEmpty());
}
var xu = this.userFactors.Row(this.userMap[userId]);
var user = new UserFeatures(xu);
return(this.RecommendUser(user, resultBuilderFactory));
}
public TResult RecommendUser <TResult>(UserFeatures user, IResultBuilderFactory <TResult> resultBuilderFactory)
{
if (user == null)
{
throw new ArgumentNullException(nameof(user));
}
var xu = user.Vector;
var yi = Vector <double> .Build.Dense(this.factors);
var resultBuilder = resultBuilderFactory.CreateBuilder(maximumCapacity: this.itemMap.Count);
foreach (var item in this.itemMap)
{
this.itemFactors.Row(item.Value, yi);
resultBuilder.Append(item.Key, xu.DotProduct(yi));
}
return(resultBuilder.ToResult());
}
public static RecommenderResult RankUsers(
this IMatrixFactorizationRecommender recommender,
UserFeatures user,
List <KeyValuePair <string, UserFeatures> > users)
{
if (recommender == null)
{
throw new ArgumentNullException(nameof(recommender));
}
if (user == null)
{
throw new ArgumentNullException(nameof(user));
}
if (users == null)
{
throw new ArgumentNullException(nameof(users));
}
return(recommender.RankUsers(user, users, RecommenderResultBuilderFactory.Instance));
}
public TResult RankUsers <TResult>(string userId, List <KeyValuePair <string, UserFeatures> > users, IResultBuilderFactory <TResult> resultBuilderFactory)
{
if (userId == null)
{
throw new ArgumentNullException(nameof(userId));
}
if (users == null)
{
throw new ArgumentNullException(nameof(users));
}
if (!this.userMap.ContainsKey(userId))
{
return(resultBuilderFactory.CreateEmpty());
}
var xu = this.userFactors.Row(this.userMap[userId]);
var user = new UserFeatures(xu);
return(this.RankUsers(user, users, resultBuilderFactory));
}
