public IEnumerable <RecommendedItem> Recommend(string userId, int topN, ISet <string> ignoredItems)
{
var result = new Dictionary <string, RecommendedItem>();
var features = _featureBuilder.BuildFeatures(userId);
foreach (var feature in features)
{
foreach (var provider in _relatedItemsProviders)
{
var relatedItems = provider.GetRelatedItems(feature.Id, topN, ignoredItems);
foreach (var item in relatedItems)
{
RecommendedItem recommendedItem;
if (!result.TryGetValue(item.Key, out recommendedItem))
{
recommendedItem = new RecommendedItem
{
ItemId = item.Key
};
result.Add(item.Key, recommendedItem);
}
var weight = item.Value * feature.Weight;
recommendedItem.Weight += weight;
if (recommendedItem.Reasons.ContainsKey(feature.Id))
{
recommendedItem.Reasons[feature.Id] += weight;
}
else
{
recommendedItem.Reasons.Add(feature.Id, weight);
}
}
}
}
return(result.Values.OrderByDescending(x => x.Weight).Take(topN).ToList());
}
public IEnumerable<RecommendedItem> Recommend(string userId, int topN, ISet<string> ignoredItems)
{
var result = new Dictionary<string, RecommendedItem>();
var features = _featureBuilder.BuildFeatures(userId);
foreach (var feature in features)
{
foreach (var provider in _relatedItemsProviders)
{
var relatedItems = provider.GetRelatedItems(feature.Id, topN, ignoredItems);
foreach (var item in relatedItems)
{
RecommendedItem recommendedItem;
if (!result.TryGetValue(item.Key, out recommendedItem))
{
recommendedItem = new RecommendedItem
{
ItemId = item.Key
};
result.Add(item.Key, recommendedItem);
}
var weight = item.Value * feature.Weight;
recommendedItem.Weight += weight;
if (recommendedItem.Reasons.ContainsKey(feature.Id))
{
recommendedItem.Reasons[feature.Id] += weight;
}
else
{
recommendedItem.Reasons.Add(feature.Id, weight);
}
}
}
}
return result.Values.OrderByDescending(x => x.Weight).Take(topN).ToList();
}