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

#include <hashDry.H>

Inheritance 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 984 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 994 of file hashDry.H.

References Aleph::maps().

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 1134 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 1139 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 989 of file hashDry.H.

References Aleph::maps().

◆ 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 1086 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.