codi::LowLevelFunctionTapeInterface< T_Real, T_Gradient, T_Identifier > Struct Template Reference

Add functions with custom derivatives to the tape. Can, e.g, be used to optimize small recurring functions like matrix matrix multiplication. More...

#include <lowLevelFunctionTapeInterface.hpp>

Inheritance diagram for codi::LowLevelFunctionTapeInterface< T_Real, T_Gradient, T_Identifier >:

Public Types
using	Gradient = T_Gradient
	See LowLevelFunctionTapeInterface.
using	Identifier = T_Identifier
	See LowLevelFunctionTapeInterface.
using	Real = T_Real
	See LowLevelFunctionTapeInterface.

Interface definition
TemporaryMemory &	getTemporaryMemory ()
	Temporary memory that can be used for dynamic data both during the evaluation and the recording.
void	pushLowLevelFunction (Config::LowLevelFunctionToken token, size_t size, ByteDataView &data)
	Push a low level function to the tape.
Config::LowLevelFunctionToken	registerLowLevelFunction (LowLevelFunctionEntry< LowLevelFunctionTapeInterface, Real, Identifier > const &entry)
	Register a low level function on the tape.
template<LowLevelFunctionEntryCallKind callType, typename... Args>
static void	callLowLevelFunction (LowLevelFunctionTapeInterface &tape, bool forward, size_t &curLLFByteDataPos, char *dataPtr, size_t &curLLFInfoDataPos, Config::LowLevelFunctionToken *const tokenPtr, Config::LowLevelFunctionDataSize *const dataSizePtr, Args &&... args)
	Internal function for evaluating a low level function entry.

Detailed Description

template<typename T_Real, typename T_Gradient, typename T_Identifier>
struct codi::LowLevelFunctionTapeInterface< T_Real, T_Gradient, T_Identifier >

Add functions with custom derivatives to the tape. Can, e.g, be used to optimize small recurring functions like matrix matrix multiplication.

A low level function like the matrix matrix multiplication can be added with this interface. First, the function needs to be registered with registerLowLevelFunction. This needs to be done only once, after this, the function is generally available. It can then be pushed as often as required with pushLowLevelFunction. Each push can be accompanied by different data, e.g., the specific matrices used by individual matrix matrix multiplications.

The user can write arbitrary data into the byte data stream. There is no requirement on the layout.

Template Parameters

T_Real	The computation type of a tape, usually chosen as ActiveType::Real.
T_Gradient	The gradient type of a tape, usually chosen as ActiveType::Gradient.
T_Identifier	The adjoint/tangent identification type of a tape, usually chosen as ActiveType::Identifier.

Member Function Documentation

callLowLevelFunction()

template<typename T_Real , typename T_Gradient , typename T_Identifier >

template<LowLevelFunctionEntryCallKind callType, typename... Args>

static void codi::LowLevelFunctionTapeInterface< T_Real, T_Gradient, T_Identifier >::callLowLevelFunction ( LowLevelFunctionTapeInterface< T_Real, T_Gradient, T_Identifier > &  tape, bool  forward, size_t &  curLLFByteDataPos, char *  dataPtr, size_t &  curLLFInfoDataPos, Config::LowLevelFunctionToken *const  tokenPtr, Config::LowLevelFunctionDataSize *const  dataSizePtr, Args &&...  args  )

static

Internal function for evaluating a low level function entry.

The positions curLLFByteDataPos, and curLLFInfoDataPos are advanced according to forward. If forward is true, they are increment otherwise they are decremented.

Parameters

tape	The tape that is evaluated.
forward	If the tape is forward evaluated.
curLLFByteDataPos	Position of dynamic data.
dataPtr	Pointer for dynamic data.
curLLFInfoDataPos	Position of info data.
tokenPtr	Pointer for token data.
dataSizePtr	Pointer for data size data.
args	Additional arguments for the function call.

Template Parameters

callType

The function type that is called.

pushLowLevelFunction()

template<typename T_Real , typename T_Gradient , typename T_Identifier >

void codi::LowLevelFunctionTapeInterface< T_Real, T_Gradient, T_Identifier >::pushLowLevelFunction	(	Config::LowLevelFunctionToken	token,
		size_t	size,
		ByteDataView &	data
	)

Push a low level function to the tape.

Allocates memory with the requested size on the byte data stream. data is initialized for accessing this allocated memory. After the call, it can be used to write data to the data stream. token is the token from registerLowLevelFunction.

See LowLevelFunctionTapeInterface for the expected data layout.

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

• include/codi/tapes/interfaces/lowLevelFunctionTapeInterface.hpp