lshkit::WeightedHammingHelper< CHUNK > Class Template Reference

Weighted hamming distance calculator. More...

#include <sketch.h>

List of all members.

Public Member Functions
	WeightedHammingHelper (unsigned chunks)
	Constructor.
void	update (const CHUNK *in, const float *asym)
	Update the information of the query point.
float	distTo (const CHUNK *in)
	Calculate the distance between the saved query point to an incoming point.
Static Public Attributes
static const unsigned	CHUNK_BIT = sizeof(CHUNK) * 8

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Detailed Description

template<typename CHUNK = unsigned char>
class lshkit::WeightedHammingHelper< CHUNK >

Weighted hamming distance calculator.

A helper class to accelerate weighted hamming distance calculation by using a lookup table. Weighted hamming distance is used in asymmetric distance evaluation between a sketch and a query point. A instance of this class holds the information of a single query point, and can be used to estimate the distance from the query point to different sketches in the database. The construction of such a helper instance is costly, so once constructed, you need to use it as many times as possible to lower the amortized cost.

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Constructor & Destructor Documentation

template<typename CHUNK = unsigned char>

lshkit::WeightedHammingHelper< CHUNK >::WeightedHammingHelper

(

unsigned

chunks

)

[inline]

Constructor.

Parameters:

chunks

number of chunks in sketch.

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Member Function Documentation

template<typename CHUNK = unsigned char>

void lshkit::WeightedHammingHelper< CHUNK >::update	(	const CHUNK *	in,
		const float *	asym
	)			[inline]

Update the information of the query point.

Parameters:

	in	sketch of the query point.
	asym	weights, the output of Sketch::apply.

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

• include/lshkit/sketch.h

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