public static double MeanAverageError(Matrix <int> ratingsMatrix, Matrix <float> weightsMatrix, RatingPredictor ratingPredictor)
{
int ratings = 0;
double totalErrors = 0;
double mae = 0;
int predictedRatings = 0;
int totalRatings = 0;
foreach (int user in ratingsMatrix.Rows)
{
List <int> userRatedItems = ratingsMatrix[user].ToList <int>();
foreach (int item in userRatedItems)
{
int originalRating = ratingsMatrix[user, item];
ratingsMatrix.remove(user, item);
totalRatings++;
double predictedRating = Math.Round(ratingPredictor.PredictRating(ratingsMatrix, weightsMatrix, user, item, true));
if (predictedRating > 0)
{
if (predictedRating > 5)
{
predictedRating = 5;
}
else if (predictedRating < 1)
{
predictedRating = 1;
}
ratings++;
predictedRatings++;
totalErrors += Math.Abs(predictedRating - originalRating);
}
ratingsMatrix[user, item] = originalRating;
}
}
mae = totalErrors / ratings;
//double coverage = (double)predictedRatings / totalRatings;
//Console.WriteLine($"Coverage: {coverage}");
return(mae);
}
public static double MeanAbsoluteUserError(Matrix <int> ratingsMatrix, Matrix <float> weightsMatrix, RatingPredictor ratingPredictor)
{
double usersMAE = 0;
foreach (int user in ratingsMatrix.Rows)
{
double totalErrors = 0;
int ratings = 0;
List <int> userRatedItems = ratingsMatrix[user].ToList <int>();
foreach (int item in userRatedItems)
{
int originalRating = ratingsMatrix[user, item];
ratingsMatrix.remove(user, item);
double predictedRating = Math.Round(ratingPredictor.PredictRating(ratingsMatrix, weightsMatrix, user, item, true));
if (predictedRating > 0)
{
if (predictedRating > 5)
{
predictedRating = 5;
}
else if (predictedRating < 1)
{
predictedRating = 1;
}
ratings++;
totalErrors += Math.Abs(predictedRating - originalRating);
}
ratingsMatrix[user, item] = originalRating;
}
if (ratings > 0)
{
usersMAE += totalErrors / ratings;
}
}
double maue = usersMAE / ratingsMatrix.Rows.Count();
return(maue);
}