MyMediaLite  3.02
Public Member Functions | Static Public Member Functions | Protected Attributes | Properties
CorrelationMatrix Class Reference

Class for computing and storing correlations and similarities. More...

Inheritance diagram for CorrelationMatrix:
SymmetricSparseMatrix< T > SparseMatrix< T > IMatrix< T > BinaryDataCorrelationMatrix RatingCorrelationMatrix BinaryCosine Jaccard WeightedBinaryCosine 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.
 CorrelationMatrix (int num_entities)
 Creates a CorrelationMatrix object for a given number of entities.
override IMatrix< T > CreateMatrix (int num_rows, int num_columns)
 Create a matrix with a given number of rows and columns.
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.
void Grow (int num_rows, int num_cols)
 Grows the matrix to the requested size, if necessary.
 SparseMatrix (int num_rows, int num_cols)
 Create a sparse matrix with a given number of rows.
double SumUp (int entity_id, ICollection< int > entities)
 Sum up the correlations between a given entity and the entities in a collection.
 SymmetricSparseMatrix (int dimension)
 Create a symmetric sparse matrix with a given dimension.
virtual IMatrix< T > Transpose ()
 Get the transpose of the matrix, i.e. a matrix where rows and columns are interchanged.
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

internal List< List< int > > index_list = new List<List<int>>()
 List of lists that stores the column indices of the entries.
int num_entities
 Number of entities, e.g. users or items.
internal List< List< T > > value_list = new List<List<T>>()
 List of lists that stores the values of the entries.

Properties

override bool IsSymmetric [get]
 returns true if the matrix is symmetric, which is generally the case for similarity matrices
override IList< Pair< int, int > > NonEmptyEntryIDs [get]
 The row and column IDs of non-empty entries in the matrix.
int NumberOfColumns [get, set]
 The number of columns of the matrix.
override int NumberOfNonEmptyEntries [get]
 The number of non-empty entries in the matrix.
int NumberOfRows [get]
 The number of rows of the matrix.
override T this[int x, int y] [get, set]
 Access the elements of the sparse matrix.
Dictionary< int, T > this[int x] [get]
 Get a row of the matrix.

Detailed Description

Class for computing and storing correlations and similarities.


Constructor & Destructor Documentation

CorrelationMatrix ( int  num_entities) [inline]

Creates a CorrelationMatrix object for a given number of entities.

Parameters:
num_entitiesnumber of entities

Member Function Documentation

void AddEntity ( int  entity_id) [inline]

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_idthe numerical ID of the entity
static CorrelationMatrix Create ( int  num_entities) [inline, static]

Creates a correlation matrix.

Gives out a useful warning if there is not enough memory

Parameters:
num_entitiesthe number of entities
Returns:
the correlation matrix
override IMatrix<T> CreateMatrix ( int  num_rows,
int  num_columns 
) [inline, virtual, inherited]

Create a matrix with a given number of rows and columns.

Parameters:
num_rowsthe number of rows
num_columnsthe number of columns
Returns:
A matrix with num_rows rows and num_column columns

Reimplemented from SparseMatrix< T >.

Reimplemented in SkewSymmetricSparseMatrix.

int [] GetNearestNeighbors ( int  entity_id,
uint  k 
) [inline]

Get the k nearest neighbors of a given entity.

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

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

Parameters:
entity_idthe entity ID
Returns:
a sorted list of all entities that are positively correlated to entitiy_id
void Grow ( int  num_rows,
int  num_cols 
) [inline, inherited]

Grows the matrix to the requested size, if necessary.

The new entries are filled with zeros.

Parameters:
num_rowsthe minimum number of rows
num_colsthe minimum number of columns

Implements IMatrix< T >.

static CorrelationMatrix ReadCorrelationMatrix ( StreamReader  reader) [inline, static]

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:
readerthe StreamReader to read from
SparseMatrix ( int  num_rows,
int  num_cols 
) [inline, inherited]

Create a sparse matrix with a given number of rows.

Parameters:
num_rowsthe number of rows
num_colsthe number of columns
double SumUp ( int  entity_id,
ICollection< int >  entities 
) [inline]

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

Parameters:
entity_idthe numerical ID of the entity
entitiesa collection containing the numerical IDs of the entities to compare to
Returns:
the correlation sum
SymmetricSparseMatrix ( int  dimension) [inline, inherited]

Create a symmetric sparse matrix with a given dimension.

Parameters:
dimensionthe dimension (number of rows/columns)
virtual IMatrix<T> Transpose ( ) [inline, virtual, inherited]

Get the transpose of the matrix, i.e. a matrix where rows and columns are interchanged.

Returns:
the transpose of the matrix (copy)

Implements IMatrix< T >.

void Write ( StreamWriter  writer) [inline]

Write out the correlations to a StreamWriter.

Parameters:
writerA StreamWriter

Member Data Documentation

internal List<List<int> > index_list = new List<List<int>>() [protected, inherited]

List of lists that stores the column indices of the entries.

int num_entities [protected]

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

internal List<List<T> > value_list = new List<List<T>>() [protected, inherited]

List of lists that stores the values of the entries.


Property Documentation

override IList<Pair<int, int> > NonEmptyEntryIDs [get, inherited]

The row and column IDs of non-empty entries in the matrix.

The row and column IDs of non-empty entries in the matrix

Reimplemented from SparseMatrix< T >.

int NumberOfColumns [get, set, inherited]

The number of columns of the matrix.

The number of columns of the matrix

Implements IMatrix< T >.

override int NumberOfNonEmptyEntries [get, inherited]

The number of non-empty entries in the matrix.

The number of non-empty entries in the matrix

Reimplemented from SparseMatrix< T >.

int NumberOfRows [get, inherited]

The number of rows of the matrix.

The number of rows of the matrix

Implements IMatrix< T >.

override T this[int x, int y] [get, set, inherited]

Access the elements of the sparse matrix.

Parameters:
xthe row ID
ythe column ID

Reimplemented from SparseMatrix< T >.

Reimplemented in SkewSymmetricSparseMatrix.

Dictionary<int, T> this[int x] [get, inherited]

Get a row of the matrix.

Parameters:
xthe row ID

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