lshkit::RepeatHash< LSH > Class Template Reference

Apply a random hash to the concatenation a number of hash values. More...

#include <composite.h>

Inheritance diagram for lshkit::RepeatHash< LSH >:

List of all members.

Public Types
typedef LSH	Super
typedef LSH::Domain	Domain
Public Member Functions
template<typename RNG>
void	reset (const Parameter &param, RNG &rng)
template<typename RNG>
	RepeatHash (const Parameter &param, RNG &rng)
unsigned	getRange () const
unsigned	operator() (Domain obj) const
template<class Archive>
void	serialize (Archive &ar, const unsigned int version)
Protected Attributes
std::vector< Super >	lsh_
std::vector< unsigned >	a_
Classes
struct	Parameter

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Detailed Description

template<typename LSH>
class lshkit::RepeatHash< LSH >

Apply a random hash to the concatenation a number of hash values.

This composition is to workaround the case where the range of individual LSHes are so large that the concatenation can not be held in a single unsgined int. The method is to further hash the concatenated value. Specifically, if <h1, h2, ..., hN> are the original values, this composition produces (a1*h1 + a2*h2 + aN*hN), with a1~aN being random unsigned integers. The range of the produced LSH is 0 (the whole range of unsigned).

The domain of the LSH remains the same. The new parameter is defined as:

      struct Parameter {
          unsigned repeat;     // # of LSHes to concatenate
          ...                  // all parameters of the base LSH are inherited.
      };

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

• include/lshkit/composite.h

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