private void ComputeAllDeviations()
{
foreach (var articleA in _articles)
{
foreach (var articleB in _articles)
{
if (articleA == articleB)
{
_deviations[articleA, articleB] = new Deviation(0, 0);
_deviations[articleB, articleA] = new Deviation(0, 0);
break;
}
var deviation = ComputeDeviation(articleA, articleB);
_deviations[articleA, articleB] = deviation;
_deviations[articleB, articleA] = new Deviation(-deviation.Value, deviation.Cardinality);
}
}
}
private Deviation ComputeDeviation(int articleA, int articleB)
{
var deviation = new Deviation(0, 0);
var usersRatedA = _ratedBy[articleA];
var usersRatedB = _ratedBy[articleB];
foreach (var user in usersRatedA)
{
if (!usersRatedB.Contains(user))
{
continue;
}
deviation.Update(_ratings[user, articleA] - _ratings[user, articleB]);
}
return(deviation);
}
