Pearson Class Reference
Correlation class for Pearson correlation.
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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.
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override void | ComputeCorrelations (IRatings ratings, EntityType entity_type) |
| Compute correlations for given ratings.
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int[] | GetNearestNeighbors (int entity_id, uint k) |
| Get the k nearest neighbors of a given entity.
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IList< int > | GetPositivelyCorrelatedEntities (int entity_id) |
| Get all entities that are positively correlated to an entity, sorted by correlation.
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| Pearson (int num_entities) |
| Constructor. Create a Pearson correlation matrix.
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double | SumUp (int entity_id, ICollection< int > entities) |
| Sum up the correlations between a given entity and the entities in a collection.
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void | Write (StreamWriter writer) |
| Write out the correlations to a StreamWriter.
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Static Public Member Functions |
static float | ComputeCorrelation (IRatings ratings, EntityType entity_type, int i, int j, float shrinkage) |
| Compute correlations between two entities for given ratings.
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static CorrelationMatrix | Create (int num_entities) |
| Creates a correlation matrix.
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static CorrelationMatrix | Create (IRatings ratings, EntityType entity_type, float shrinkage) |
| Create a Pearson correlation matrix from given data.
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static CorrelationMatrix | ReadCorrelationMatrix (StreamReader reader) |
| Creates a CorrelationMatrix from the lines of a StreamReader.
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Public Attributes |
float | shrinkage = 10 |
| shrinkage parameter
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Protected Attributes |
int | num_entities |
| Number of entities, e.g. users or items.
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Properties |
override bool | IsSymmetric [get] |
| returns true if the matrix is symmetric, which is generally the case for similarity matrices
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override float | this [int i, int j] [get, set] |
Detailed Description
Correlation class for Pearson correlation.
http://en.wikipedia.org/wiki/Pearson_correlation
Constructor & Destructor Documentation
Pearson |
( |
int |
num_entities |
) |
[inline] |
Constructor. Create a Pearson correlation matrix.
- 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 |
static float ComputeCorrelation |
( |
IRatings |
ratings, |
|
|
EntityType |
entity_type, |
|
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int |
i, |
|
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int |
j, |
|
|
float |
shrinkage | |
|
) |
| | [inline, static] |
Compute correlations between two entities for given ratings.
- Parameters:
-
| ratings | the rating data |
| entity_type | the entity type, either USER or ITEM |
| i | the ID of first entity |
| j | the ID of second entity |
| shrinkage | the shrinkage parameter |
override void ComputeCorrelations |
( |
IRatings |
ratings, |
|
|
EntityType |
entity_type | |
|
) |
| | [inline, virtual] |
Compute correlations for given ratings.
- Parameters:
-
| ratings | the rating data |
| entity_type | the entity type, either USER or ITEM |
Reimplemented from RatingCorrelationMatrix.
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
Create a Pearson correlation matrix from given data.
- Parameters:
-
| ratings | the ratings data |
| entity_type | the entity type, either USER or ITEM |
| shrinkage | a shrinkage parameter |
- Returns:
- the complete Pearson correlation matrix
int [] GetNearestNeighbors |
( |
int |
entity_id, |
|
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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:
-
- 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:
-
Member Data Documentation
Number of entities, e.g. users or items.
The documentation for this class was generated from the following file: