CRTP mixin providing statistics and configuration for chained hash tables. More...

#include <hashDry.H>

Inheritance diagram for HashStats< HashTbl >:

Collaboration diagram for HashStats< HashTbl >:

Classes
struct	Stats
	Statistics about chain length distribution. More...

Public Member Functions
Stats	stats () const
	Computes statistics about chain length distribution.

void	print_stats (const Stats &stats) const
	Prints statistics to standard output.

void	set_upper_alpha (float _upper_alpha)
	Sets the upper load factor threshold.

void	set_lower_alpha (float _lower_alpha)
	Sets the lower load factor threshold.

constexpr float	get_lower_alpha () const noexcept
	Returns the lower load factor threshold.

constexpr float	get_upper_alpha () const noexcept
	Returns the upper load factor threshold.

Private Member Functions
HashTbl *	me ()
	Returns a pointer to the derived class (CRTP pattern).

const HashTbl *	const_me () const
	Returns a const pointer to the derived class (CRTP pattern).

Static Private Member Functions
static void	update_stat_len (DynArray< size_t > &lens, size_t i)
	Updates chain length histogram.

Private Attributes
float	lower_alpha
	Lower load factor threshold for shrinking.

float	upper_alpha
	Upper load factor threshold for growing.

size_t	busy_slots_counter = 0
	Number of buckets with at least one entry.

size_t	N = 0
	Total number of entries.

Detailed Description

template<class HashTbl>
class HashStats< HashTbl >

CRTP mixin providing statistics and configuration for chained hash tables.

This class provides statistics gathering and load factor configuration for hash tables using separate chaining (linked lists per bucket). It uses CRTP for static polymorphism.

Template Parameters

HashTbl The derived hash table class.

Provided Operations:

stats() - Compute chain length statistics
print_stats() - Display statistics
set_lower_alpha() / set_upper_alpha() - Configure load factor thresholds
get_lower_alpha() / get_upper_alpha() - Query thresholds

See also: LhashTable

Definition at line 991 of file hashDry.H.

Member Function Documentation

◆ const_me()

template<class HashTbl >

const HashTbl * HashStats< HashTbl >::const_me ( ) const

inlineprivate

Returns a const pointer to the derived class (CRTP pattern).

Returns: Const pointer to this object cast to const HashTbl*.

Definition at line 1001 of file hashDry.H.

References Aleph::divide_and_conquer_partition_dp().

Referenced by HashStats< HashTbl >::print_stats(), and HashStats< HashTbl >::stats().

◆ get_lower_alpha()

template<class HashTbl >

constexpr float HashStats< HashTbl >::get_lower_alpha ( ) const

inlineconstexprnoexcept

Returns the lower load factor threshold.

Returns: The lower alpha threshold.

Definition at line 1141 of file hashDry.H.

References HashStats< HashTbl >::lower_alpha.

◆ get_upper_alpha()

template<class HashTbl >

constexpr float HashStats< HashTbl >::get_upper_alpha ( ) const

inlineconstexprnoexcept

Returns the upper load factor threshold.

Returns: The upper alpha threshold.

Definition at line 1146 of file hashDry.H.

References HashStats< HashTbl >::upper_alpha.

◆ me()

template<class HashTbl >

HashTbl * HashStats< HashTbl >::me ( )

inlineprivate

Returns a pointer to the derived class (CRTP pattern).

Returns: Pointer to this object cast to HashTbl*.

Definition at line 996 of file hashDry.H.

References Aleph::divide_and_conquer_partition_dp().

◆ print_stats()

template<class HashTbl >

void HashStats< HashTbl >::print_stats ( const Stats & stats ) const

inline

Prints statistics to standard output.

Displays formatted statistics including capacity, size, busy slots, average chain length, standard deviation, load factor, and chain length distribution.

Parameters

stats Statistics object to print.

Definition at line 1093 of file hashDry.H.

References HashStats< HashTbl >::Stats::avg, HashStats< HashTbl >::busy_slots_counter, HashStats< HashTbl >::const_me(), HashStats< HashTbl >::Stats::lens, Aleph::DynArray< T >::size(), sqrt(), HashStats< HashTbl >::stats(), and HashStats< HashTbl >::Stats::var.

◆ set_lower_alpha()

template<class HashTbl >

void HashStats< HashTbl >::set_lower_alpha ( float _lower_alpha )

inline

Sets the lower load factor threshold.

When the load factor drops below this value after a removal, the table automatically shrinks (if auto-resize is enabled).

Parameters

_lower_alpha New lower threshold.

Exceptions

std::domain_error If _lower_alpha >= upper_alpha.

Definition at line 1130 of file hashDry.H.

References ah_domain_error_if, Aleph::divide_and_conquer_partition_dp(), HashStats< HashTbl >::lower_alpha, and HashStats< HashTbl >::upper_alpha.

◆ set_upper_alpha()

template<class HashTbl >

void HashStats< HashTbl >::set_upper_alpha ( float _upper_alpha )

inline

Sets the upper load factor threshold.

When the load factor exceeds this value, the table automatically grows (if auto-resize is enabled).

Parameters

_upper_alpha New upper threshold.

Exceptions

std::domain_error If _upper_alpha <= lower_alpha.

Definition at line 1114 of file hashDry.H.

References ah_domain_error_if, Aleph::divide_and_conquer_partition_dp(), HashStats< HashTbl >::lower_alpha, and HashStats< HashTbl >::upper_alpha.

◆ stats()

template<class HashTbl >

Stats HashStats< HashTbl >::stats ( ) const

inline

Computes statistics about chain length distribution.

Iterates through all buckets to compute the distribution of chain lengths, along with mean and variance.

Returns: Stats object containing chain length statistics.

Complexity: O(n + m) where n is entries and m is capacity.

Definition at line 1047 of file hashDry.H.

References HashStats< HashTbl >::Stats::avg, HashStats< HashTbl >::const_me(), Aleph::count(), HashStats< HashTbl >::Stats::lens, Aleph::DynArray< T >::size(), HashStats< HashTbl >::stats(), Aleph::sum(), HashStats< HashTbl >::update_stat_len(), and HashStats< HashTbl >::Stats::var.

Referenced by HashStats< HashTbl >::print_stats(), HashStats< HashTbl >::stats(), Aleph::adversarial_search_detail::store_adversarial_transposition(), and TEST().

◆ update_stat_len()

template<class HashTbl >

static void HashStats< HashTbl >::update_stat_len	(	DynArray< size_t > &	lens,
		size_t	i
	)

inlinestaticprivate

Updates chain length histogram.

Parameters

lens	The histogram array to update.
i	The chain length to record.

Definition at line 1028 of file hashDry.H.

References Aleph::DynArray< T >::exist(), and Aleph::DynArray< T >::touch().

Referenced by HashStats< HashTbl >::stats().

Member Data Documentation

◆ busy_slots_counter

template<class HashTbl >

size_t HashStats< HashTbl >::busy_slots_counter = 0

private

Number of buckets with at least one entry.

Definition at line 1005 of file hashDry.H.

Referenced by HashStats< HashTbl >::print_stats().

◆ lower_alpha

template<class HashTbl >

float HashStats< HashTbl >::lower_alpha

private

Lower load factor threshold for shrinking.

Definition at line 1003 of file hashDry.H.

Referenced by HashStats< HashTbl >::get_lower_alpha(), HashStats< HashTbl >::set_lower_alpha(), and HashStats< HashTbl >::set_upper_alpha().

◆ N

template<class HashTbl >

size_t HashStats< HashTbl >::N = 0

private

Total number of entries.

Definition at line 1006 of file hashDry.H.

◆ upper_alpha

template<class HashTbl >

float HashStats< HashTbl >::upper_alpha

private

Upper load factor threshold for growing.

Definition at line 1004 of file hashDry.H.

Referenced by HashStats< HashTbl >::get_upper_alpha(), HashStats< HashTbl >::set_lower_alpha(), and HashStats< HashTbl >::set_upper_alpha().

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

hashDry.H

Classes

Public Member Functions

Private Member Functions

Static Private Member Functions

Private Attributes

Detailed Description

Member Function Documentation

◆ const_me()

◆ get_lower_alpha()

◆ get_upper_alpha()

◆ me()

◆ print_stats()

◆ set_lower_alpha()

◆ set_upper_alpha()

◆ stats()

◆ update_stat_len()

Member Data Documentation

◆ busy_slots_counter

◆ lower_alpha

◆ N

◆ upper_alpha