gem5::Memoizer< Ret, Args > Class Template Reference

This class takes a function as a constructor argument and memoizes it: every time the function gets invoked through the Memoizer object (see operator()), the result gets saved in the internal cache, ready to be retrieved next time an invokation is made with the same arguments. More...

#include <memoizer.hh>

Public Types
using	ret_type = Ret
using	args_type = std::tuple<Args...>

Public Member Functions
constexpr	Memoizer (Ret(*_func)(Args...))
	Memoizer ()=delete
	Memoizer (const Memoizer &rhs)=delete
Memoizer &	operator= (const Memoizer &rhs)=delete
auto	operator() (Args... args) const
void	flush ()
	Clear the memoization cache.

Protected Member Functions
bool	cached (args_type args) const
	True if the passed value is cached, false otherwise.
size_t	cacheSize () const
	Return the size of the memoizer cache.

Private Member Functions
constexpr void	validateMemoizer ()
	Validate the memoizer and produce an error if the function signature contains a reference.
template<size_t Start, size_t End, size_t Inc, class F>
constexpr void	iterateTupleArgs (F &&func)

Private Attributes
const std::function< Ret(Args...)>	func
	Memoized function.
std::map< args_type, ret_type >	cache
	Result cache.

Detailed Description

template<typename Ret, typename... Args>
class gem5::Memoizer< Ret, Args >

This class takes a function as a constructor argument and memoizes it: every time the function gets invoked through the Memoizer object (see operator()), the result gets saved in the internal cache, ready to be retrieved next time an invokation is made with the same arguments.

Example usage:

int fibonacci(int n);

Memoizer fibonacci_memo(fibonacci); fibonacci_memo(5);

Not every function is eligible for memoization. We explicitly validate the memoizer at compile time and produce an error if the function signature contains a reference.

There are two ways to discard a memoization

1) Delete the Memoizer object 2) Use the Memoizer::flush method

In some cases there is little or no reason to discard a memoization (like in the fibonacci example, where fibonacci(k) always returns the same value for the same input k) The memoizer could be used in more complex cases, where a change in the global state affects the output of the function, which effectively invalidates the cached results. It is up to the client to understand when memoization is no longer valid and to flush the result cache as a consequence.

Definition at line 82 of file memoizer.hh.

Member Typedef Documentation

args_type

template<typename Ret, typename... Args>

using gem5::Memoizer< Ret, Args >::args_type = std::tuple<Args...>

Definition at line 86 of file memoizer.hh.

ret_type

template<typename Ret, typename... Args>

using gem5::Memoizer< Ret, Args >::ret_type = Ret

Definition at line 85 of file memoizer.hh.

Constructor & Destructor Documentation

Memoizer() [1/3]

template<typename Ret, typename... Args>

gem5::Memoizer< Ret, Args >::Memoizer ( Ret(* _func )(Args...) )

inlineconstexpr

Definition at line 88 of file memoizer.hh.

References func, and validateMemoizer().

Referenced by Memoizer(), and operator=().

Memoizer() [2/3]

template<typename Ret, typename... Args>

gem5::Memoizer< Ret, Args >::Memoizer ( )

delete

Memoizer() [3/3]

template<typename Ret, typename... Args>

gem5::Memoizer< Ret, Args >::Memoizer ( const Memoizer< Ret, Args > & rhs )

delete

References Memoizer().

Member Function Documentation

cached()

template<typename Ret, typename... Args>

bool gem5::Memoizer< Ret, Args >::cached ( args_type args ) const

inlineprotected

True if the passed value is cached, false otherwise.

Definition at line 116 of file memoizer.hh.

References cache.

cacheSize()

template<typename Ret, typename... Args>

size_t gem5::Memoizer< Ret, Args >::cacheSize ( ) const

inlineprotected

Return the size of the memoizer cache.

Definition at line 123 of file memoizer.hh.

References cache.

flush()

template<typename Ret, typename... Args>

void gem5::Memoizer< Ret, Args >::flush ( )

inline

Clear the memoization cache.

Definition at line 111 of file memoizer.hh.

References cache.

iterateTupleArgs()

template<typename Ret, typename... Args>

template<size_t Start, size_t End, size_t Inc, class F>

void gem5::Memoizer< Ret, Args >::iterateTupleArgs ( F && func )

inlineconstexprprivate

Definition at line 146 of file memoizer.hh.

References func, and iterateTupleArgs().

Referenced by iterateTupleArgs(), and validateMemoizer().

operator()()

template<typename Ret, typename... Args>

auto gem5::Memoizer< Ret, Args >::operator() ( Args... args ) const

inline

Definition at line 99 of file memoizer.hh.

References cache, and func.

operator=()

template<typename Ret, typename... Args>

Memoizer & gem5::Memoizer< Ret, Args >::operator= ( const Memoizer< Ret, Args > & rhs )

delete

References Memoizer().

validateMemoizer()

template<typename Ret, typename... Args>

void gem5::Memoizer< Ret, Args >::validateMemoizer ( )

inlineconstexprprivate

Validate the memoizer and produce an error if the function signature contains a reference.

Definition at line 134 of file memoizer.hh.

References gem5::ArmISA::i, and iterateTupleArgs().

Referenced by Memoizer().

Member Data Documentation

cache

template<typename Ret, typename... Args>

std::map<args_type, ret_type> gem5::Memoizer< Ret, Args >::cache

mutableprivate

Result cache.

Definition at line 158 of file memoizer.hh.

Referenced by cached(), cacheSize(), flush(), and operator()().

func

template<typename Ret, typename... Args>

const std::function<Ret(Args...)> gem5::Memoizer< Ret, Args >::func

private

Memoized function.

Definition at line 156 of file memoizer.hh.

Referenced by iterateTupleArgs(), Memoizer(), and operator()().

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

• base/memoizer.hh