sdsl::select_support_mcl< b, pattern_len > Class Template Reference

A class supporting constant time select queries (proposed by Munro/Clark, 1996) enhanced by broadword computing tricks. More...

#include <select_support_mcl.hpp>

Inherits sdsl::select_support.

List of all members.

Public Types
typedef bit_vector	bit_vector_type
Public Member Functions
	select_support_mcl (const int_vector< 1 > *v=NULL)
	select_support_mcl (const select_support_mcl< b, pattern_len > &ss)
void	init (const int_vector< 1 > *v=NULL)
	Initalization method for select_support.
void	init_slow (const int_vector< 1 > *v=NULL)
const size_type	select (size_type i) const
	Select function.
const size_type	operator() (size_type i) const
	Alias for select(i).
size_type	serialize (std::ostream &out, structure_tree_node *v=NULL, std::string name="") const
	Serialize the select_support to an out file stream.
void	load (std::istream &in, const int_vector< 1 > *v=NULL)
	Load the select_support from an in file stream.
void	set_vector (const int_vector< 1 > *v=NULL)
	This method sets the supported bit_vector.
select_support_mcl< b, pattern_len > &	operator= (const select_support_mcl &ss)
void	swap (select_support_mcl< b, pattern_len > &ss)
	Swap operator.
bool	operator== (const select_support_mcl< b, pattern_len > &ss) const
	Equality Operator.
bool	operator!= (const select_support_mcl< b, pattern_len > &ss) const
	Unequality Operator.

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Detailed Description

template<uint8_t b = 1, uint8_t pattern_len = 1>
class sdsl::select_support_mcl< b, pattern_len >

A class supporting constant time select queries (proposed by Munro/Clark, 1996) enhanced by broadword computing tricks.

Space usage

The space usage of the data structure depends on the number of of ones in the original bitvector $b$. We store the position of every $4096$th set bit (called L1-sampled bits) of $b$. This takes in the worst case bits. Next, (1) if the distance of two adjacent L1-sampled bits $b[i]$ and $b[j]$ is greater or equal than $^4 n$, then we store each of the 4096 positions of the set $b$ in [i..j-1] with ${n}$ bits. This results in at most $ {4096 n}{^4 n}={4096}{^3 n}$ bits per bit. For a bitvector of 1GB, i.e. we get about 0.01 bits per bit. If the $j-i+1 < ^4 n$ then (2) we store the relative position of every $64$th set bit (called L2-sampled bits) in b[i..j-1] in at most $4 n$ bits per L2-sampled bits. An pessimistic upper bound for the space would be bit per bit (since $ n 6$. It is very pessimistic, since we store the relative position in $(j-i+1) n$ bits.

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Member Function Documentation

template<uint8_t b, uint8_t pattern_len>

void sdsl::select_support_mcl< b, pattern_len >::init

(

const int_vector< 1 > *

v = NULL

)

[virtual]

Initalization method for select_support.

Init takes no arguments and should be called before the first call to the select method if not

• load is called to initialize the select_support or
• the constructor is called with the pointer to the supported bit_vector.

  See also:

  select, load.

Implements sdsl::select_support.

template<uint8_t b, uint8_t pattern_len>

void sdsl::select_support_mcl< b, pattern_len >::load	(	std::istream &	in,
		const int_vector< 1 > *	v = NULL
	)		[virtual]

Load the select_support from an in file stream.

Load an previously serialized select_support from a std::istream. This method could replace the call of init before the first call of the select method.

Parameters:

in	The std::istream to load the select_support.
v	The bit_vector to be supported.

See also:

init, select.

Implements sdsl::select_support.

template<uint8_t b, uint8_t pattern_len>

bool sdsl::select_support_mcl< b, pattern_len >::operator!=

(

const select_support_mcl< b, pattern_len > &

ss

)

const

Unequality Operator.

Two select_support_mcls are not equal if any member variable are not equal. Required for the Equality Comparable Concept of the STL.

See also:

operator==

template<uint8_t b, uint8_t pattern_len>

bool sdsl::select_support_mcl< b, pattern_len >::operator==

(

const select_support_mcl< b, pattern_len > &

ss

)

const

Equality Operator.

Two select_support_mcls are equal if all member variables are equal. Required for the Equality Comparable Concept of the STL.

See also:

operator!=

template<uint8_t b, uint8_t pattern_len>

const select_support_mcl< b, pattern_len >::size_type sdsl::select_support_mcl< b, pattern_len >::select

(

size_type

i

)

const [inline, virtual]

Select function.

See also:

select_support.select

Implements sdsl::select_support.

template<uint8_t b, uint8_t pattern_len>

void sdsl::select_support_mcl< b, pattern_len >::set_vector

(

const int_vector< 1 > *

v = NULL

)

[virtual]

This method sets the supported bit_vector.

Note:

Call the init function before you call select the first time after you changed the supported bit_vector.

Implements sdsl::select_support.

template<uint8_t b, uint8_t pattern_len>

void sdsl::select_support_mcl< b, pattern_len >::swap

(

select_support_mcl< b, pattern_len > &

ss

)

Swap operator.

This swap operator swaps two select_support_mcls in constant time.

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

• sdsl/include/sdsl/select_support_mcl.hpp