RatingCorrelationMatrix Class Reference

CorrelationMatrix that computes correlations over rating data. More...

Inheritance diagram for RatingCorrelationMatrix:
CorrelationMatrix Pearson

List of all members.

Public Member Functions

void AddEntity (int entity_id)
 Add an entity to the CorrelationMatrix by growing it to the requested size.
abstract void ComputeCorrelations (IRatings ratings, EntityType entity_type)
 Compute the correlations for a given entity type from a rating dataset.
int[] GetNearestNeighbors (int entity_id, uint k)
 Get the k nearest neighbors of a given entity.
IList< int > GetPositivelyCorrelatedEntities (int entity_id)
 Get all entities that are positively correlated to an entity, sorted by correlation.
 RatingCorrelationMatrix (int num_entities)
 Constructor.
double SumUp (int entity_id, ICollection< int > entities)
 Sum up the correlations between a given entity and the entities in a collection.
void Write (StreamWriter writer)
 Write out the correlations to a StreamWriter.

Static Public Member Functions

static CorrelationMatrix Create (int num_entities)
 Creates a correlation matrix.
static CorrelationMatrix ReadCorrelationMatrix (StreamReader reader)
 Creates a CorrelationMatrix from the lines of a StreamReader.

Protected Attributes

int num_entities
 Number of entities, e.g. users or items.

Properties

override bool IsSymmetric [get]
 returns true if the matrix is symmetric, which is generally the case for similarity matrices

Detailed Description

CorrelationMatrix that computes correlations over rating data.


Constructor & Destructor Documentation

RatingCorrelationMatrix ( int  num_entities  )  [inline]

Constructor.

Parameters:
num_entities the number of entities

Member Function Documentation

void AddEntity ( int  entity_id  )  [inline, inherited]

Add an entity to the CorrelationMatrix by growing it to the requested size.

Note that you still have to correctly compute and set the entity's correlation values

Parameters:
entity_id the numerical ID of the entity
abstract void ComputeCorrelations ( IRatings  ratings,
EntityType  entity_type 
) [pure virtual]

Compute the correlations for a given entity type from a rating dataset.

Parameters:
ratings the rating data
entity_type the EntityType - either USER or ITEM

Implemented in Pearson.

static CorrelationMatrix Create ( int  num_entities  )  [inline, static, inherited]

Creates a correlation matrix.

Gives out a useful warning if there is not enough memory

Parameters:
num_entities the number of entities
Returns:
the correlation matrix
int [] GetNearestNeighbors ( int  entity_id,
uint  k 
) [inline, inherited]

Get the k nearest neighbors of a given entity.

Parameters:
entity_id the numerical ID of the entity
k the neighborhood size
Returns:
an array containing the numerical IDs of the k nearest neighbors
IList<int> GetPositivelyCorrelatedEntities ( int  entity_id  )  [inline, inherited]

Get all entities that are positively correlated to an entity, sorted by correlation.

Parameters:
entity_id the entity ID
Returns:
a sorted list of all entities that are positively correlated to entitiy_id
static CorrelationMatrix ReadCorrelationMatrix ( StreamReader  reader  )  [inline, static, inherited]

Creates a CorrelationMatrix from the lines of a StreamReader.

In the first line, we expect to be the number of entities. All the other lines have the format

		      EntityID1 EntityID2 Correlation
		    

where EntityID1 and EntityID2 are non-negative integers and Correlation is a floating point number.

Parameters:
reader the StreamReader to read from
double SumUp ( int  entity_id,
ICollection< int >  entities 
) [inline, inherited]

Sum up the correlations between a given entity and the entities in a collection.

Parameters:
entity_id the numerical ID of the entity
entities a collection containing the numerical IDs of the entities to compare to
Returns:
the correlation sum
void Write ( StreamWriter  writer  )  [inline, inherited]

Write out the correlations to a StreamWriter.

Parameters:
writer A StreamWriter

Member Data Documentation

int num_entities [protected, inherited]

Number of entities, e.g. users or items.


The documentation for this class was generated from the following file:
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