Class NegativeDataGeneratorMapping<TInstanceSource, TInstance, TUser, TItem, TFeatureSource, TFeatureValues>

Represents a generator of negative ratings.

Inheritance
Object
NegativeDataGeneratorMapping<TInstanceSource, TInstance, TUser, TItem, TFeatureSource, TFeatureValues>
Implements
IStarRatingRecommenderMapping<TInstanceSource, RatingInstance<TUser, TItem, Byte>, TUser, TItem, Int32, TFeatureSource, TFeatureValues>
IRatingRecommenderMapping<TInstanceSource, RatingInstance<TUser, TItem, Byte>, TUser, TItem, Int32, TFeatureSource, TFeatureValues>
IRecommenderMapping<TInstanceSource, RatingInstance<TUser, TItem, Byte>, TUser, TItem, TFeatureSource, TFeatureValues>
Inherited Members
Namespace: Microsoft.ML.Probabilistic.Learners.Mappings
Assembly: Microsoft.ML.Probabilistic.Learners.Recommender.dll
Syntax
[Serializable]
public class NegativeDataGeneratorMapping<TInstanceSource, TInstance, TUser, TItem, TFeatureSource, TFeatureValues> : IStarRatingRecommenderMapping<TInstanceSource, RatingInstance<TUser, TItem, byte>, TUser, TItem, int, TFeatureSource, TFeatureValues>, IRatingRecommenderMapping<TInstanceSource, RatingInstance<TUser, TItem, byte>, TUser, TItem, int, TFeatureSource, TFeatureValues>, IRecommenderMapping<TInstanceSource, RatingInstance<TUser, TItem, byte>, TUser, TItem, TFeatureSource, TFeatureValues>, ICustomSerializable
Type Parameters
Name Description
TInstanceSource

The type of an instance source.
TInstance

The type of an instance.
TUser

The type of a user.
TItem

The type of an item.
TFeatureSource

The type of a feature source.
TFeatureValues

The type of the feature values.
Remarks

A description of the algorithm for negative data generation used here can be found in Section 4.1 of this paper.

Constructors

NegativeDataGeneratorMapping(IRecommenderMapping<TInstanceSource, TInstance, TUser, TItem, TFeatureSource, TFeatureValues>, Double)

Initializes a new instance of the NegativeDataGeneratorMapping<TInstanceSource, TInstance, TUser, TItem, TFeatureSource, TFeatureValues> class.

Declaration
public NegativeDataGeneratorMapping(IRecommenderMapping<TInstanceSource, TInstance, TUser, TItem, TFeatureSource, TFeatureValues> mapping, double itemHistogramAdjustment = 1.2)
Parameters
Type Name Description
IRecommenderMapping<TInstanceSource, TInstance, TUser, TItem, TFeatureSource, TFeatureValues> mapping

The top level mapping.
Double itemHistogramAdjustment

The degree to which each element of the item histogram is raised before sampling. Should be different from 1.0 if it is believed that there is some quality bar which drives popular items to be more generally liked.

NegativeDataGeneratorMapping(IReader, IRecommenderMapping<TInstanceSource, TInstance, TUser, TItem, TFeatureSource, TFeatureValues>)

Initializes a new instance of the NegativeDataGeneratorMapping<TInstanceSource, TInstance, TUser, TItem, TFeatureSource, TFeatureValues> class from a reader of a binary stream.

Declaration
public NegativeDataGeneratorMapping(IReader reader, IRecommenderMapping<TInstanceSource, TInstance, TUser, TItem, TFeatureSource, TFeatureValues> mapping)
Parameters
Type Name Description
IReader reader

The binary reader to read the state of the negative data generation mapping from.
IRecommenderMapping<TInstanceSource, TInstance, TUser, TItem, TFeatureSource, TFeatureValues> mapping

The top level mapping.

Methods

GetInstances(TInstanceSource)

Retrieves a list of instances from a given instance source.

Declaration
public IEnumerable<RatingInstance<TUser, TItem, byte>> GetInstances(TInstanceSource instanceSource)
Parameters
Type Name Description
TInstanceSource instanceSource

The instance source to retrieve instances from.
Returns
Type Description
IEnumerable<RatingInstance<TUser, TItem, Byte>>

The list of retrieved instances.

GetItem(TInstanceSource, RatingInstance<TUser, TItem, Byte>)

Extracts an item from a given instance.

Declaration
public TItem GetItem(TInstanceSource instanceSource, RatingInstance<TUser, TItem, byte> instance)
Parameters
Type Name Description
TInstanceSource instanceSource

The instance source providing the instance.
RatingInstance<TUser, TItem, Byte> instance

The instance to extract the item from.
Returns
Type Description
TItem

The extracted item.

GetItemFeatures(TFeatureSource, TItem)

Provides the features for a given item.

Declaration
public TFeatureValues GetItemFeatures(TFeatureSource featureSource, TItem item)
Parameters
Type Name Description
TFeatureSource featureSource

The source of the features.
TItem item

The item to provide the features for.
Returns
Type Description
TFeatureValues

The features for item.

GetRating(TInstanceSource, RatingInstance<TUser, TItem, Byte>)

Extracts a rating from a given instance.

Declaration
public int GetRating(TInstanceSource instanceSource, RatingInstance<TUser, TItem, byte> instance)
Parameters
Type Name Description
TInstanceSource instanceSource

The instance source providing the instance.
RatingInstance<TUser, TItem, Byte> instance

The instance to extract the rating from.
Returns
Type Description
Int32

The extracted rating.

GetRatingInfo(TInstanceSource)

Provides the object describing how ratings in the dataset map to the stars.

Declaration
public IStarRatingInfo<int> GetRatingInfo(TInstanceSource instanceSource)
Parameters
Type Name Description
TInstanceSource instanceSource

The instance source.
Returns
Type Description
IStarRatingInfo<Int32>

The object describing how ratings provided by the instance source map to stars.

GetUser(TInstanceSource, RatingInstance<TUser, TItem, Byte>)

Extracts a user from a given instance.

Declaration
public TUser GetUser(TInstanceSource instanceSource, RatingInstance<TUser, TItem, byte> instance)
Parameters
Type Name Description
TInstanceSource instanceSource

The instance source providing the instance.
RatingInstance<TUser, TItem, Byte> instance

The instance to extract the user from.
Returns
Type Description
TUser

The extracted user.

GetUserFeatures(TFeatureSource, TUser)

Provides the features for a given user.

Declaration
public TFeatureValues GetUserFeatures(TFeatureSource featureSource, TUser user)
Parameters
Type Name Description
TFeatureSource featureSource

The source of the features.
TUser user

The user to provide the features for.
Returns
Type Description
TFeatureValues

The features for user.

SaveForwardCompatible(IWriter)

Saves the negative data generation mapping using the specified writer to a binary stream.

Declaration
public void SaveForwardCompatible(IWriter writer)
Parameters
Type Name Description
IWriter writer

The writer to save the negative data generation mapping to.

Implements

Extension Methods