/// <summary>
/// Create a point from a sparse set of (x,y) pairs where the x is the MovieId minus one (to make it zero-based) and the
/// y is the Rating.
/// </summary>
/// <param name="dimensions">Total number of dimensions, including those which are missing a value, hence have
/// no corresponding pair (MovieId,Rating).</param>
/// <returns>A new HyperContrastedPoint or SparsePoint, whose UniqueId is the ReviewerId.</returns>
public UnsignedPoint ToPoint(int dimensions)
{
if (Point == null)
{
var useHyperContrastedPoints = true;
if (useHyperContrastedPoints)
{
Point = new HyperContrastedPoint(
MovieIds.Select(movieId => movieId - 1).ToList(),
Ratings.Select(rating => (uint)rating).ToList(),
dimensions,
new[] { 0U, 6U },
ReviewerId
);
}
else
{
Point = new SparsePoint(
MovieIds.Select(movieId => movieId - 1).ToList(),
Ratings.Select(rating => (uint)rating).ToList(),
dimensions,
0U,
ReviewerId
);
}
}
return(Point);
}
/// <summary>
/// Get the rating (1 to 5) given by this reviewer for the given movie, if known, or null.
/// </summary>
/// <param name="movieId">Movie whose rating is sought.</param>
/// <returns>A one to five rating, or null, if this reviewer has not reviewed the movie.</returns>
public int?Review(int movieId)
{
var position = MovieIds.BinarySearch(movieId);
if (position >= 0)
{
return(Ratings[position]);
}
else
{
return(null);
}
}
/// <summary>
/// Add a new review and maintain the MovieIds in sorted order.
/// </summary>
/// <param name="movieId">Movie that weas reviewed.
/// If this reviewer already has a review for the movie, replace it with the new rating.
/// </param>
/// <param name="rating">Rating of the movie, from one to five.</param>
public void Add(int movieId, uint rating)
{
if (Count == 0 || MovieIds.Last() < movieId)
{
MovieIds.Add(movieId);
Ratings.Add((byte)rating);
}
else
{
var position = MovieIds.BinarySearch(movieId);
if (position >= 0)
{
Ratings[position] = (byte)rating;
}
else
{
// It is not possible for the position to be after the end of the array,
// because we already tested for the case where the movieId is larger than the last value.
position = ~position;
MovieIds.Insert(position, movieId);
Ratings.Insert(position, (byte)rating);
}
}
}
