operations_research::bop::NonOrderedSetHasher< IntType > Class Template Reference

Detailed Description

template<typename IntType>
class operations_research::bop::NonOrderedSetHasher< IntType >

A simple and efficient class to hash a given set of integers in [0, n). It uses O(n) memory and produces a good hash (random linear function).

Definition at line 220 of file bop_ls.h.

#include <bop_ls.h>

Public Member Functions
	NonOrderedSetHasher (absl::BitGenRef random)
void	Initialize (int size)
	Initializes the NonOrderedSetHasher to hash sets of integer in [0, n).
void	IgnoreElement (IntType e)
uint64_t	Hash (const std::vector< IntType > &set) const
uint64_t	Hash (IntType e) const
bool	IsInitialized () const
	Returns true if Initialize() has been called with a non-zero size.

Constructor & Destructor Documentation

NonOrderedSetHasher()

template<typename IntType>

operations_research::bop::NonOrderedSetHasher< IntType >::NonOrderedSetHasher ( absl::BitGenRef random )

inlineexplicit

Definition at line 222 of file bop_ls.h.

Member Function Documentation

Hash() [1/2]

template<typename IntType>

uint64_t operations_research::bop::NonOrderedSetHasher< IntType >::Hash ( const std::vector< IntType > & set ) const

inline

Returns the hash of the given set. The hash is independent of the set order, but there must be no duplicate element in the set. This uses a simple random linear function which has really good hashing properties.

Definition at line 239 of file bop_ls.h.

Hash() [2/2]

template<typename IntType>

uint64_t operations_research::bop::NonOrderedSetHasher< IntType >::Hash ( IntType e ) const

inline

The hash of a set is simply the XOR of all its elements. This allows to compute an hash incrementally or without the need of a vector<>.

Definition at line 247 of file bop_ls.h.

IgnoreElement()

template<typename IntType>

void operations_research::bop::NonOrderedSetHasher< IntType >::IgnoreElement ( IntType e )

inline

Ignores the given set element in all subsequent hash computation. Note that this will be reset by the next call to Initialize().

Definition at line 234 of file bop_ls.h.

Initialize()

template<typename IntType>

void operations_research::bop::NonOrderedSetHasher< IntType >::Initialize ( int size )

inline

Initializes the NonOrderedSetHasher to hash sets of integer in [0, n).

Definition at line 225 of file bop_ls.h.

IsInitialized()

template<typename IntType>

bool operations_research::bop::NonOrderedSetHasher< IntType >::IsInitialized ( ) const

inline

Returns true if Initialize() has been called with a non-zero size.

Definition at line 250 of file bop_ls.h.

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

• ortools/bop/bop_ls.h