/// <summary>
/// Computes the number of original observations, positive
/// ratings, and negative ratings for each user and item
/// </summary>
/// <param name="userRatingCounts">A map from each user to their rating counts.</param>
/// <param name="itemRatingCounts">A map from each item to its rating counts.</param>
private void ComputeRatingCounts(
out IDictionary <string, RatingCounts> userRatingCounts,
out IDictionary <string, RatingCounts> itemRatingCounts)
{
Rand.Restart(12347);
var positiveOnlyMapping = new PositiveOnlyDataMapping();
var negativeDataGeneratorMapping = positiveOnlyMapping.WithGeneratedNegativeData(1.0);
userRatingCounts = new Dictionary <string, RatingCounts>();
itemRatingCounts = new Dictionary <string, RatingCounts>();
// Count the number of positive observations for each user and item.
foreach (var instance in positiveOnlyMapping.GetInstances(this.positiveOnlyDataset))
{
var user = positiveOnlyMapping.GetUser(this.positiveOnlyDataset, instance);
var item = positiveOnlyMapping.GetItem(this.positiveOnlyDataset, instance);
RatingCounts ratingCounts;
if (!userRatingCounts.TryGetValue(user, out ratingCounts))
{
ratingCounts = new RatingCounts();
userRatingCounts.Add(user, ratingCounts);
}
++ratingCounts.Original;
if (!itemRatingCounts.TryGetValue(item, out ratingCounts))
{
ratingCounts = new RatingCounts();
itemRatingCounts.Add(item, ratingCounts);
}
++ratingCounts.Original;
}
// Compute the number of positive and negative ratings generated for each user and item.
foreach (var instance in negativeDataGeneratorMapping.GetInstances(this.positiveOnlyDataset))
{
var user = negativeDataGeneratorMapping.GetUser(this.positiveOnlyDataset, instance);
var item = negativeDataGeneratorMapping.GetItem(this.positiveOnlyDataset, instance);
var rating = negativeDataGeneratorMapping.GetRating(this.positiveOnlyDataset, instance);
if (rating == 1)
{
++userRatingCounts[user].Positive;
++itemRatingCounts[item].Positive;
}
else if (rating == 0)
{
++userRatingCounts[user].Negative;
++itemRatingCounts[item].Negative;
}
}
}
// Constructor for database end.
public ProductRating(long pid, string languageString, int nativeTotalReviewCount, int externalTotalReviewCount,
int combinedTotalReviewCount, RatingCounts nativeRatings, RatingCounts externalRatings)
{
PID = pid;
LanguageString = languageString;
NativeRatings = nativeRatings;
ExternalRatings = externalRatings;
NativeTotalReviewCount = nativeTotalReviewCount;
ExternalTotalReviewCount = externalTotalReviewCount;
CombinedTotalReviewCount = combinedTotalReviewCount;
}
