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

#include <customAdjointVectorEvaluationTapeInterface.hpp>

Inheritance diagram for codi::CustomAdjointVectorEvaluationTapeInterface< T_Position >:

[legend]

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 AdjointVector >
void	evaluate (Position const &start, Position const &end, AdjointVector &&data)
	Perform a reverse evaluation for a part of the tape. It hast to hold start >= end.

template<typename AdjointVector >
void	evaluateForward (Position const &start, Position const &end, AdjointVector &&data)
	Perform a forward evaluation of a part of the tape. It has to hold start <= end.

template<typename AdjointVector >
void	clearCustomAdjoints (Position const &start, Position const &end, AdjointVector &&data)
	Clear all adjoint values, that is, set them to zero.

template<typename InternalAdjoints >
InternalAdjoints	getInternalAdjoints ()
	Obtain a representation of the tape's internal adjoint vector that can be used as custom adjoints.

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, and for clearing adjoints.

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, and the additional clearing method allows clearing the custom adjoint vector according to the recorded tape.

The adjoint vector type (template parameter AdjointVector in the member functions) must be a accessible with operator[]. Suitable choices are pointers, e.g., Adjoint*, or classes with overloaded operator[] like std::vector<Adjoint>.

codi::AdjointVectorTraits::GradientImplementation must be specialized for AdjointVector. The type of the vector entries deduced from these traits (gradient type) must support the following operators:

operator =
operator *(Tape::Real, Adjoint) (Scalar multiplication from the left)
operator += The gradient type 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;
  using Gradient = codi::Direction<double, 2>;
 
  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);
  Gradient* adjoints = new Gradient[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

◆ clearCustomAdjoints()

template<typename T_Position >

template<typename AdjointVector >

void codi::CustomAdjointVectorEvaluationTapeInterface< T_Position >::clearCustomAdjoints	(	Position const &	start,
		Position const &	end,
		AdjointVector &&	data )

Clear all adjoint values, that is, set them to zero.

Clear custom adjoint vector according to a tape recording.

Template Parameters

AdjointVector See CustomAdjointVectorEvaluationTapeInterface documentation.

◆ evaluate()

template<typename T_Position >

template<typename AdjointVector >

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

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

Tape evaluation with a custom adjoint vector.

Template Parameters

AdjointVector See CustomAdjointVectorEvaluationTapeInterface documentation.

◆ evaluateForward()

template<typename T_Position >

template<typename AdjointVector >

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

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

Tape evaluation with a custom adjoint vector.

Template Parameters

AdjointVector See CustomAdjointVectorEvaluationTapeInterface documentation.

◆ getInternalAdjoints()

template<typename T_Position >

template<typename InternalAdjoints >

InternalAdjoints codi::CustomAdjointVectorEvaluationTapeInterface< T_Position >::getInternalAdjoints ( )

Obtain a representation of the tape's internal adjoint vector that can be used as custom adjoints.

To avoid that functionality has to be implemented both for custom, external and internal adjoints, this method provides access to the internal adjoints so that they can be used as if they were custom adjoints.

Warning: If you use this method, proceed with care. If internal adjoints are modified due to side effect of other methods, the object returned here might become invalid, or, conversely, modifications of the returned object other than reading/writing adjoints might interfere with the tape's management of internal adjoints.

Template Parameters

InternalAdjoints Placeholder for the implementation-dependent return type.

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

include/codi/tapes/interfaces/customAdjointVectorEvaluationTapeInterface.hpp

Public Types

Public Member Functions

Detailed Description

Member Function Documentation

◆ clearCustomAdjoints()

◆ evaluate()

◆ evaluateForward()

◆ getInternalAdjoints()