codi::CustomAdjointVectorEvaluationTapeInterface< T_Position > Struct Template Reference

Allows user defined vectors for the forward and adjoint evaluation. More...

#include <customAdjointVectorEvaluationTapeInterface.hpp>

Inheritance diagram for codi::CustomAdjointVectorEvaluationTapeInterface< T_Position >:

Public Types
using	Position = T_Position
	See CustomAdjointVectorEvaluationTapeInterface.
Public Types inherited from codi::ForwardEvaluationTapeInterface< T_Position >
using	Position = T_Position
	See ForwardEvaluationTapeInterface.
Public Types inherited from codi::PositionalEvaluationTapeInterface< T_Position >
using	Position = T_Position
	See PositionalEvaluationTapeInterface.

Public Member Functions
Interface definition
template<typename Adjoint >
void	evaluate (Position const &start, Position const &end, Adjoint *data)
	Perform a reverse evaluation for a part of the tape. It hast to hold start >= end.
template<typename Adjoint >
void	evaluateForward (Position const &start, Position const &end, Adjoint *data)
	Perform a forward evaluation of a part of the tape. It has to hold start <= end.
Public Member Functions inherited from codi::ForwardEvaluationTapeInterface< T_Position >
void	evaluateForward (Position const &start, Position const &end, AdjointsManagement adjointsManagement=AdjointsManagement::Automatic)
	Perform a forward evaluation of a part of the tape. It has to hold start <= end.
void	evaluateForward (AdjointsManagement adjointsManagement=AdjointsManagement::Automatic)
	Perform a forward evaluation of the full tape.
Public Member Functions inherited from codi::PositionalEvaluationTapeInterface< T_Position >
void	evaluate (Position const &start, Position const &end, AdjointsManagement adjointsManagement=AdjointsManagement::Automatic)
	Perform a reverse evaluation for a part of the tape. It hast to hold start >= end.
void	clearAdjoints (Position const &start, Position const &end, AdjointsManagement adjointsManagement=AdjointsManagement::Automatic)
	Clear all adjoints that would be set in a tape evaluation from start to end. It has to hold start >= end.
Position	getPosition () const
	Current position of the tape.
Position	getZeroPosition () const
	Initial position of the tape.
void	resetTo (Position const &pos, bool resetAdjoints=true, AdjointsManagement adjointsManagement=AdjointsManagement::Automatic)
	Reset the tape to the provided position.

Detailed Description

template<typename T_Position>
struct codi::CustomAdjointVectorEvaluationTapeInterface< T_Position >

Allows user defined vectors for the forward and adjoint evaluation.

See Tape Interface Design for a general overview of the tape interface design in CoDiPack.

The two additional evaluate methods allow for the evaluation of the tape with a custom adjoint vector. The type of the vector must support the following operators:

• operator =
• operator *(Tape::Real, Adjoint) (Scalar multiplication from the left)
• operator += It must also specialize codi::GradientTraits::TraitsImplementation.

Here is an example for an evaluation with a custom adjoint vector (documentation/examples/customAdjointVectorEvaluationTapeInterface.cpp):

  using Real = codi::RealReverse;
  using Tape = typename Real::Tape;
 
  Tape& tape = Real::getTape();
 
  // Recording
  Real x = 10.0;
 
  tape.setActive();
  tape.registerInput(x);
 
  Real y1 = 42.0 * x * x;
  Real y2 = 20.0 * x * x * x;
 
  tape.registerOutput(y1);
  tape.registerOutput(y2);
 
  tape.setPassive();
 
  // Reverse evaluation
  size_t adjointSize = tape.getParameter(codi::TapeParameters::LargestIdentifier);
  codi::Direction<double, 2>* adjoints = new codi::Direction<double, 2>[adjointSize + 1];
 
  adjoints[y1.getIdentifier()] = {1.0, 0.0};
  adjoints[y2.getIdentifier()] = {0.0, 1.0};
 
  tape.evaluate(tape.getPosition(), tape.getZeroPosition(), adjoints); // Full tape evaluation
 
  std::cout << "Gradient of dy1/dx: " << adjoints[x.getIdentifier()][0] << std::endl;
  std::cout << "Gradient of dy2/dx: " << adjoints[x.getIdentifier()][1] << std::endl;
 
  delete [] adjoints;

Template Parameters

T_Position

Global tape position, usually chosen as Tape::Position.

Member Function Documentation

evaluate()

template<typename T_Position >

template<typename Adjoint >

void codi::CustomAdjointVectorEvaluationTapeInterface< T_Position >::evaluate	(	Position const &	start,
		Position const &	end,
		Adjoint *	data
	)

Perform a reverse evaluation for a part of the tape. It hast to hold start >= end.

Automatic adjoints management involves bounds checking, resizing, and locking, see AdjointsManagement for details.

Template Parameters

Adjoint

See CustomAdjointVectorEvaluationTapeInterface documentation.

evaluateForward()

template<typename T_Position >

template<typename Adjoint >

void codi::CustomAdjointVectorEvaluationTapeInterface< T_Position >::evaluateForward	(	Position const &	start,
		Position const &	end,
		Adjoint *	data
	)

Perform a forward evaluation of a part of the tape. It has to hold start <= end.

Automatic adjoints management involves bounds checking, resizing, and locking, see AdjointsManagement for details.

Template Parameters

Adjoint

See CustomAdjointVectorEvaluationTapeInterface documentation.

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

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