sofa::core::componentmodel::behavior::BaseForceField Class Reference

Component computing forces within simulated bodies. More...

#include <BaseForceField.h>

Inheritance diagram for sofa::core::componentmodel::behavior::BaseForceField:

Collaboration diagram for sofa::core::componentmodel::behavior::BaseForceField:


Public Member Functions
virtual	~BaseForceField ()
virtual int	getFracturedEdge ()
Vector operations
virtual void	addForce ()=0
	Given the current position and velocity states, update the current force vector by computing and adding the forces associated with this ForceField.
virtual void	addDForce (double kFactor=1.0, double bFactor=0.0)=0
	Compute the force derivative given a small displacement from the position and velocity used in the previous call to addForce().
virtual void	addDForceV (double kFactor=1.0, double bFactor=0.0)=0
	Same as addDForce(), except the velocity vector should be used instead of dx.
virtual void	addMBKdx (double mFactor, double bFactor, double kFactor)
	Accumulate the contribution of M, B, and/or K matrices multiplied by the dx vector with the given coefficients.
virtual void	addMBKv (double mFactor, double bFactor, double kFactor)
	Accumulate the contribution of M, B, and/or K matrices multiplied by the v vector with the given coefficients.
virtual double	getPotentialEnergy ()=0
	Get the potential energy associated to this ForceField.
Matrix operations
virtual void	addKToMatrix (sofa::defaulttype::BaseMatrix *matrix, double kFact, unsigned int &offset)
	Compute the system matrix corresponding to k K.
virtual void	addBToMatrix (sofa::defaulttype::BaseMatrix *matrix, double bFact, unsigned int &offset)
	Compute the system matrix corresponding to b B.
virtual void	addMBKToMatrix (sofa::defaulttype::BaseMatrix *matrix, double mFact, double bFact, double kFact, unsigned int &offset)
	Compute the system matrix corresponding to m M + b B + k K.

Detailed Description

Component computing forces within simulated bodies.

This class define the abstract API common to all force fields. A force field computes forces applied to one or more simulated body given its current position and velocity.

Forces can be internal to a given body (attached to one MechanicalState, see the ForceField class), or link several bodies together (such as contact forces, see the InteractionForceField class).

For implicit integration schemes, it must also compute the derivative ( df, given a displacement dx ).

Definition at line 62 of file BaseForceField.h.

Constructor & Destructor Documentation

virtual sofa::core::componentmodel::behavior::BaseForceField::~BaseForceField ( ) [inline, virtual]

Definition at line 65 of file BaseForceField.h.

Member Function Documentation

void sofa::core::componentmodel::behavior::BaseForceField::addBToMatrix	(	sofa::defaulttype::BaseMatrix *	matrix,
		double	bFact,
		unsigned int &	offset
	)			`[virtual]`

Compute the system matrix corresponding to b B.

Parameters:

	matrix	matrix to add the result to
	bFact	coefficient for damping contributions (i.e. first derivatives term in the ODE)
	offset	current row/column offset

Definition at line 58 of file BaseForceField.cpp.

Referenced by addMBKToMatrix().

virtual void sofa::core::componentmodel::behavior::BaseForceField::addDForce	(	double	kFactor = `1.0`,
		double	bFactor = `0.0`
	)			`[pure virtual]`

Compute the force derivative given a small displacement from the position and velocity used in the previous call to addForce().

The derivative should be directly derived from the computations done by addForce. Any forces neglected in addDForce will be integrated explicitly (i.e. using its value at the beginning of the timestep).

If the ForceField can be represented as a matrix, this method computes $ df += kFactor K dx + bFactor B dx $

Referenced by addMBKdx(), and sofa::simulation::MechanicalComputeDfVisitor::fwdForceField().

virtual void sofa::core::componentmodel::behavior::BaseForceField::addDForceV	(	double	kFactor = `1.0`,
		double	bFactor = `0.0`
	)			`[pure virtual]`

Same as addDForce(), except the velocity vector should be used instead of dx.

If the ForceField can be represented as a matrix, this method computes $ df += kFactor K v + bFactor B v $

Referenced by addMBKv(), and sofa::simulation::MechanicalComputeDfVisitor::fwdForceField().

virtual void sofa::core::componentmodel::behavior::BaseForceField::addForce ( ) [pure virtual]

Given the current position and velocity states, update the current force vector by computing and adding the forces associated with this ForceField.

If the ForceField can be represented as a matrix, this method computes $ f += B v + K x $

Referenced by sofa::simulation::MechanicalComputeForceVisitor::fwdForceField(), and sofa::simulation::AnimateVisitor::fwdInteractionForceField().

void sofa::core::componentmodel::behavior::BaseForceField::addKToMatrix	(	sofa::defaulttype::BaseMatrix *	matrix,
		double	kFact,
		unsigned int &	offset
	)			`[virtual]`

Compute the system matrix corresponding to k K.

Parameters:

	matrix	matrix to add the result to
	kFact	coefficient for stiffness contributions (i.e. DOFs term in the ODE)
	offset	current row/column offset

Reimplemented in sofa::component::forcefield::BeamFEMForceField< DataTypes >, sofa::component::forcefield::HexahedronFEMForceField< DataTypes >, sofa::component::forcefield::TetrahedralCorotationalFEMForceField< DataTypes >, and sofa::component::forcefield::TetrahedronFEMForceField< DataTypes >.

Definition at line 53 of file BaseForceField.cpp.

Referenced by addMBKToMatrix().

void sofa::core::componentmodel::behavior::BaseForceField::addMBKdx	(	double	mFactor,
		double	bFactor,
		double	kFactor
	)			`[virtual]`

Accumulate the contribution of M, B, and/or K matrices multiplied by the dx vector with the given coefficients.

This method computes $ df += mFactor M dx + bFactor B dx + kFactor K dx $ In most cases only one of these matrices will be non-null for a given component. For forcefields without mass it simply calls addDForce.

Parameters:

	mFact	coefficient for mass contributions (i.e. second-order derivatives term in the ODE)
	bFact	coefficient for damping contributions (i.e. first derivatives term in the ODE)
	kFact	coefficient for stiffness contributions (i.e. DOFs term in the ODE)

Reimplemented in sofa::core::componentmodel::behavior::Mass< DataTypes >.

Definition at line 41 of file BaseForceField.cpp.

References addDForce().

Referenced by sofa::simulation::MechanicalAddMBKdxVisitor::fwdForceField().

void sofa::core::componentmodel::behavior::BaseForceField::addMBKToMatrix	(	sofa::defaulttype::BaseMatrix *	matrix,
		double	mFact,
		double	bFact,
		double	kFact,
		unsigned int &	offset
	)			`[virtual]`

Compute the system matrix corresponding to m M + b B + k K.

Parameters:

	matrix	matrix to add the result to
	mFact	coefficient for mass contributions (i.e. second-order derivatives term in the ODE)
	bFact	coefficient for damping contributions (i.e. first derivatives term in the ODE)
	kFact	coefficient for stiffness contributions (i.e. DOFs term in the ODE)
	offset	current row/column offset

Reimplemented in sofa::core::componentmodel::behavior::Mass< DataTypes >.

Definition at line 63 of file BaseForceField.cpp.

References addBToMatrix(), and addKToMatrix().

Referenced by sofa::simulation::MechanicalAddMBK_ToMatrixVisitor::fwdForceField().

void sofa::core::componentmodel::behavior::BaseForceField::addMBKv	(	double	mFactor,
		double	bFactor,
		double	kFactor
	)			`[virtual]`

Accumulate the contribution of M, B, and/or K matrices multiplied by the v vector with the given coefficients.

This method computes $ df += mFactor M v + bFactor B v + kFactor K v $ In most cases only one of these matrices will be non-null for a given component. For forcefields without mass it simply calls addDForceV.

Parameters:

	mFact	coefficient for mass contributions (i.e. second-order derivatives term in the ODE)
	bFact	coefficient for damping contributions (i.e. first derivatives term in the ODE)
	kFact	coefficient for stiffness contributions (i.e. DOFs term in the ODE)

Reimplemented in sofa::core::componentmodel::behavior::Mass< DataTypes >.

Definition at line 47 of file BaseForceField.cpp.

References addDForceV().

Referenced by sofa::simulation::MechanicalAddMBKdxVisitor::fwdForceField().

virtual int sofa::core::componentmodel::behavior::BaseForceField::getFracturedEdge ( ) [inline, virtual]

Reimplemented in sofa::component::forcefield::TriangularFEMForceField< DataTypes >.

Definition at line 159 of file BaseForceField.h.

virtual double sofa::core::componentmodel::behavior::BaseForceField::getPotentialEnergy ( ) [pure virtual]

Get the potential energy associated to this ForceField.

Used to extimate the total energy of the system by some post-stabilization techniques.

Referenced by sofa::simulation::MechanicalComputeEnergyVisitor::fwdForceField().

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

framework/sofa/core/componentmodel/behavior/BaseForceField.h
framework/sofa/core/componentmodel/behavior/BaseForceField.cpp

sofa::core::componentmodel::behavior::BaseForceField Class Reference

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation