codi::CustomAdjointVectorHelper< T_Type, T_Gradient > Struct Template Reference

Allows for an arbitrary adjoint evaluation of a recorded tape. More...

#include <customAdjointVectorHelper.hpp>

Inheritance diagram for codi::CustomAdjointVectorHelper< T_Type, T_Gradient >:

Public Types
using	Base = CustomAdjointVectorInterface<Type>
	Abbreviation for the base class.
using	Gradient = T_Gradient
	See CustomAdjointVectorHelper.
using	Identifier = typename Type::Identifier
	See LhsExpressionInterface.
using	Position = typename Tape::Position
	See PositionalEvaluationTapeInterface.
using	Real = typename Type::Real
	See LhsExpressionInterface.
using	Tape = typename Type::Tape
	See LhsExpressionInterface.
using	Type = T_Type
	< See CustomAdjointVectorHelper.
Public Types inherited from codi::CustomAdjointVectorInterface< T_Type >
using	Identifier = typename Type::Identifier
	See LhsExpressionInterface.
using	Position = typename Tape::Position
	See PositionalEvaluationTapeInterface.
using	Real = typename Type::Real
	See LhsExpressionInterface.
using	Tape = typename Type::Tape
	See LhsExpressionInterface.
using	Type = T_Type
	See CustomAdjointVectorInterface.

Public Member Functions
	CustomAdjointVectorHelper ()
	Constructor.
	~CustomAdjointVectorHelper ()
	Destructor.
Implementation of CustomAdjointVectorInterface interface
void	clearAdjoints ()
	Set all adjoints to zero.
void	deleteAdjointVector ()
	Delete the adjoint vector.
void	evaluate (Position const &start, Position const &end)
	Perform a full reverse evaluation of the tape.
void	evaluateForward (Position const &start, Position const &end)
	Perform a forward evaluation of a part of the tape. It has to hold start <= end.
VectorAccessInterface< Real, Identifier > *	getVectorInterface ()
	Get a new general interface to the adjoint vector.
void	evaluate ()
	Perform a full reverse evaluation of the tape.
void	evaluateForward ()
	Perform a forward evaluation of a part of the tape. It has to hold start <= end.
Gradient access methods
Gradient const &	getGradient (Identifier const &identifier) const
	Get a constant reference to the gradient.
Gradient &	gradientUnchecked (Identifier const &identifier)
	Get a reference to the gradient. Unchecked access.
Gradient const &	gradientUnchecked (Identifier const &identifier) const
	Get a constant reference to the gradient. Unchecked access.
Gradient &	gradient (Identifier const &identifier)
	Get a reference to the gradient. Checked access.
Gradient const &	gradient (Identifier const &identifier) const
	Get a constant reference to the gradient. Checked access.
void	setGradient (Identifier &identifier, Gradient const &gradientValue)
	Set the gradient. Checked access.
Public Member Functions inherited from codi::CustomAdjointVectorInterface< T_Type >
	CustomAdjointVectorInterface ()
	Constructor.
virtual	~CustomAdjointVectorInterface ()
	Destructor.
void	evaluate ()
	Perform a full reverse evaluation of the tape.
void	evaluateForward ()
	Perform a forward evaluation of a part of the tape. It has to hold start <= end.
void	setTape (Tape &tape)
	Set the tape for the evaluations.
Tape &	getTape ()
	Get the tape for the evaluations.

Protected Attributes
AdjointVectorAccess< Real, Identifier, Gradient * > *	adjointInterface
	Last created adjoint interface.
std::vector< Gradient >	adjointVector
	Custom adjoint vector.
Gradient const	constZeroValue
	Temporary constant zero value.
Gradient	zeroValue
	Temporary zero value.

Detailed Description

template<typename T_Type, typename T_Gradient>
struct codi::CustomAdjointVectorHelper< T_Type, T_Gradient >

Allows for an arbitrary adjoint evaluation of a recorded tape.

The evaluation of a reverse AD tape is independent of the recording of the tape. For example, the reverse evaluation can be performed simultaneously on differtent adjoint vectors or with a vector mode that is not the same as the vector mode implied by the CoDiPack type.

An example for a different vector mode and the general usage is:

  // Step 1: Perform a regular recording
  for(size_t i = 0; i < 5; ++i) {
    tape.registerInput(x[i]);
  }
 
  func(x, 5, y);
 
  tape.registerOutput(y[0]);
  tape.registerOutput(y[1]);
 
  tape.setPassive();
 
  codi::CustomAdjointVectorHelper<Real, codi::Direction<double, 2> > vh; // Step 2: Create the vector helper
  vh.gradient(y[0].getIdentifier())[0] = 1.0;             // Step 3: Set the seeding in the vector helper
  vh.gradient(y[1].getIdentifier())[1] = 1.0;
 
  vh.evaluate();                                          // Step 4: Call evaluate on the vector helper.
 
  // Step 5: Get the gradients from the vector helper.
  codi::Jacobian<double> jacobian(2,5);
  for(size_t i = 0; i < 5; ++i) {
    jacobian(0,i) = vh.getGradient(x[i].getIdentifier())[0];
    jacobian(1,i) = vh.getGradient(x[i].getIdentifier())[1];
  }

The major difference in using the vector helper is that you cannot interact with the adjoints directly, e.g. via the codi::LhsExpressionInterface::getGradient or codi::LhsExpressionInterface::setGradient functions. Instead, you extract the identifier from the AD variable via the codi::LhsExpressionInterface::getIdentifier() functions. The identifier is then used to access the adjoint values via the vector helper, e.g. for seeding or extraction.

For details on custom vector evaluations see CustomAdjointVectorEvaluationTapeInterface.

Template Parameters

T_Type	The underlying CoDiPack type.
T_Gradient	Type of the entries of the custom adjoint vector.

Member Function Documentation

clearAdjoints()

template<typename T_Type, typename T_Gradient>

void codi::CustomAdjointVectorHelper< T_Type, T_Gradient >::clearAdjoints ( )

inlinevirtual

Set all adjoints to zero.

Implements codi::CustomAdjointVectorInterface< T_Type >.

deleteAdjointVector()

template<typename T_Type, typename T_Gradient>

void codi::CustomAdjointVectorHelper< T_Type, T_Gradient >::deleteAdjointVector ( )

inlinevirtual

Delete the adjoint vector.

Implements codi::CustomAdjointVectorInterface< T_Type >.

evaluate() [1/2]

template<typename T_Type, typename T_Gradient>

void codi::CustomAdjointVectorInterface< Type >::evaluate ( )

inline

Perform a full reverse evaluation of the tape.

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

evaluate() [2/2]

template<typename T_Type, typename T_Gradient>

void codi::CustomAdjointVectorHelper< T_Type, T_Gradient >::evaluate ( Position const & start, Position const & end )

inlinevirtual

Perform a full reverse evaluation of the tape.

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

Implements codi::CustomAdjointVectorInterface< T_Type >.

evaluateForward() [1/2]

template<typename T_Type, typename T_Gradient>

void codi::CustomAdjointVectorInterface< Type >::evaluateForward ( )

inline

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.

evaluateForward() [2/2]

template<typename T_Type, typename T_Gradient>

void codi::CustomAdjointVectorHelper< T_Type, T_Gradient >::evaluateForward ( Position const & start, Position const & end )

inlinevirtual

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.

Implements codi::CustomAdjointVectorInterface< T_Type >.

getVectorInterface()

template<typename T_Type, typename T_Gradient>

VectorAccessInterface< Real, Identifier > * codi::CustomAdjointVectorHelper< T_Type, T_Gradient >::getVectorInterface ( )

inlinevirtual

Get a new general interface to the adjoint vector.

Implements codi::CustomAdjointVectorInterface< T_Type >.

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

• include/codi/tools/helpers/customAdjointVectorHelper.hpp