gmx::HashedMap< T > Class Template Reference

#include <gromacs/domdec/hashedmap.h>

Description

template<typename T>
class gmx::HashedMap< T >

Unordered key to value mapping.

Efficiently manages mapping from integer keys to values. Note that this basically implements a subset of the functionality of std::unordered_map, but is an order of magnitude faster.

Public Member Functions
	HashedMap (int numElementsEstimate)
	Constructor. More...
int	size () const
	Returns the number of elements.
int	bucket_count () const
	Returns the number of buckets, i.e. the number of possible hashes.
void	insert (int key, const T &value)
	Inserts entry, key should not already be present. More...
void	insert_or_assign (int key, const T &value)
	Inserts an entry when the key is not present, otherwise sets the value. More...
void	erase (int key)
	Delete the entry for key key, when present. More...
T *	find (int key)
	Returns a pointer to the value for the given key or nullptr when not present. More...
const T *	find (int key) const
	Returns a pointer to the value for the given key or nullptr when not present. More...
void	clear ()
	Clear all the entries in the list.
void	clearAndResizeHashTable ()
	Clear all the entries in the list and resizes the hash table. More...

Constructor & Destructor Documentation

template<typename T>

gmx::HashedMap< T >::HashedMap ( int  numElementsEstimate )

inline

Constructor.

Parameters

[in]

numElementsEstimate

An estimate of the number of elements that will be stored, used for optimizing initial performance

Note that the estimate of the number of elements is only relevant for the performance up until the first call to clear(), after which table size is optimized based on the actual number of elements.

Member Function Documentation

template<typename T>

void gmx::HashedMap< T >::clearAndResizeHashTable ( )

inline

Clear all the entries in the list and resizes the hash table.

Optimizes the size of the hash table based on the current number of elements stored.

template<typename T>

void gmx::HashedMap< T >::erase ( int  key )

inline

Delete the entry for key key, when present.

Parameters

[in]

key

The key

template<typename T>

T* gmx::HashedMap< T >::find ( int  key )

inline

Returns a pointer to the value for the given key or nullptr when not present.

Todo:

Use std::as_const when CUDA 11 is a requirement.

Parameters

[in]

key

The key

Returns

a pointer to value for the given key or nullptr when not present

template<typename T>

const T* gmx::HashedMap< T >::find ( int  key ) const

inline

Returns a pointer to the value for the given key or nullptr when not present.

Parameters

[in]

key

The key

Returns

a pointer to value for the given key or nullptr when not present

template<typename T>

void gmx::HashedMap< T >::insert ( int  key, const T &  value  )

inline

Inserts entry, key should not already be present.

Parameters

[in]	key	The key for the entry
[in]	value	The value for the entry

Exceptions

InvalidInputError

from a debug build when attempting to inser

template<typename T>

void gmx::HashedMap< T >::insert_or_assign ( int  key, const T &  value  )

inline

Inserts an entry when the key is not present, otherwise sets the value.

Parameters

[in]	key	The key for the entry
[in]	value	The value for the entry

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

• src/gromacs/domdec/domdec_specatomcomm.h
• src/gromacs/domdec/hashedmap.h