Implements the k-Nearest Neighbor lazy learning classification algorithm. More...

#include <knn.h>

Inheritance diagram for meta::classify::knn:

Classes
class	knn_exception
	Basic exception for knn interactions. More...

Public Member Functions
	knn (std::shared_ptr< index::inverted_index > idx, std::shared_ptr< index::forward_index > f_idx, uint16_t k, std::unique_ptr< index::ranker > ranker, bool weighted=false)

void	train (const std::vector< doc_id > &docs) override
	Creates a classification model based on training documents. More...

class_label	classify (doc_id d_id) override
	Classifies a document into a specific group, as determined by training data. More...

void	reset () override
	Resets any learning information associated with this classifier.

Public Member Functions inherited from meta::classify::classifier
	classifier (std::shared_ptr< index::forward_index > idx)

virtual confusion_matrix	test (const std::vector< doc_id > &docs)
	Classifies a collection document into specific groups, as determined by training data; this function will make repeated calls to classify(). More...

virtual confusion_matrix	cross_validate (const std::vector< doc_id > &input_docs, size_t k, bool even_split=false, int seed=1)
	Performs k-fold cross-validation on a set of documents. More...

Static Public Attributes
static const std::string	id = "knn"
	Identifier for this classifier.

Private Member Functions
class_label	select_best_label (const std::vector< std::pair< doc_id, double >> &scored, const std::vector< std::pair< class_label, uint16_t >> &sorted) const

Private Attributes
std::shared_ptr< index::inverted_index >	inv_idx_
	the inverted index used for ranking

uint16_t	k_
	the value of k in k-NN

std::unique_ptr< index::ranker >	ranker_
	The ranker that is used to score the queries in the index.

std::unordered_set< doc_id >	legal_docs_
	documents that are "legal" to be used in the results

const bool	weighted_
	Whether we want the neighbors to be weighted by distance or not.

Additional Inherited Members
Protected Attributes inherited from meta::classify::classifier
std::shared_ptr< index::forward_index >	idx_
	the index that the classifer is run on

Detailed Description

Implements the k-Nearest Neighbor lazy learning classification algorithm.

Constructor & Destructor Documentation

meta::classify::knn::knn	(	std::shared_ptr< index::inverted_index >	idx,
		std::shared_ptr< index::forward_index >	f_idx,
		uint16_t	k,
		std::unique_ptr< index::ranker >	ranker,
		bool	weighted = `false`
	)

Parameters

idx	The index to run the classifier on
ranker	The ranker to be used internally
k	The value of k in k-NN
args	Arguments to the chosen ranker constructor
weighted	Whether to weight the neighbors by distance to the query

void meta::classify::knn::train ( const std::vector< doc_id > & docs )

overridevirtual

Creates a classification model based on training documents.

Parameters

docs	The training documents

class_label meta::classify::knn::classify ( doc_id d_id )

overridevirtual

Classifies a document into a specific group, as determined by training data.

Parameters

d_id	The document to classify

class_label meta::classify::knn::select_best_label	(	const std::vector< std::pair< doc_id, double >> &	scored,
		const std::vector< std::pair< class_label, uint16_t >> &	sorted
	)		const

private

Parameters

scored
sorted

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