This class implements an interaction between groups of four particles that varies with the torsion angle between them according to the Ryckaert-Bellemans potential. More...

#include <RBTorsionForce.h>

Inheritance diagram for RBTorsionForce:

Public Member Functions
	RBTorsionForce ()
	Create a RBTorsionForce.

int	getNumTorsions () const
	Get the number of Ryckaert-Bellemans torsion terms in the potential function.

int	addTorsion (int particle1, int particle2, int particle3, int particle4, double c0, double c1, double c2, double c3, double c4, double c5)
	Add a Ryckaert-Bellemans torsion term to the force field.

void	getTorsionParameters (int index, int &particle1, int &particle2, int &particle3, int &particle4, double &c0, double &c1, double &c2, double &c3, double &c4, double &c5) const
	Get the force field parameters for a Ryckaert-Bellemans torsion term.

void	setTorsionParameters (int index, int particle1, int particle2, int particle3, int particle4, double c0, double c1, double c2, double c3, double c4, double c5)
	Set the force field parameters for a Ryckaert-Bellemans torsion term.

void	updateParametersInContext (Context &context)
	Update the per-torsion parameters in a Context to match those stored in this Force object.

Public Member Functions inherited from Force
	Force ()

virtual	~Force ()

int	getForceGroup () const
	Get the force group this Force belongs to.

void	setForceGroup (int group)
	Set the force group this Force belongs to.

Protected Member Functions
ForceImpl *	createImpl ()
	When a Context is created, it invokes this method on each Force in the System.

Protected Member Functions inherited from Force
ForceImpl &	getImplInContext (Context &context)
	Get the ForceImpl corresponding to this Force in a Context.

ContextImpl &	getContextImpl (Context &context)
	Get the ContextImpl corresponding to a Context.

Detailed Description

This class implements an interaction between groups of four particles that varies with the torsion angle between them according to the Ryckaert-Bellemans potential.

To use it, create an RBTorsionForce object then call addTorsion() once for each torsion. After a torsion has been added, you can modify its force field parameters by calling setTorsionParameters(). This will have no effect on Contexts that already exist unless you call updateParametersInContext().

Constructor & Destructor Documentation

RBTorsionForce ( )

Create a RBTorsionForce.

Member Function Documentation

int addTorsion	(	int	particle1,
		int	particle2,
		int	particle3,
		int	particle4,
		double	c0,
		double	c1,
		double	c2,
		double	c3,
		double	c4,
		double	c5
	)

Add a Ryckaert-Bellemans torsion term to the force field.

Parameters

particle1	the index of the first particle forming the torsion
particle2	the index of the second particle forming the torsion
particle3	the index of the third particle forming the torsion
particle4	the index of the fourth particle forming the torsion
c0	the coefficient of the constant term, measured in kJ/mol
c1	the coefficient of the 1st order term, measured in kJ/mol
c2	the coefficient of the 2nd order term, measured in kJ/mol
c3	the coefficient of the 3rd order term, measured in kJ/mol
c4	the coefficient of the 4th order term, measured in kJ/mol
c5	the coefficient of the 5th order term, measured in kJ/mol

Returns: the index of the torsion that was added

ForceImpl* createImpl ( )

protectedvirtual

When a Context is created, it invokes this method on each Force in the System.

It should create a new ForceImpl object which can be used by the context for calculating forces. The ForceImpl will be deleted automatically when the Context is deleted.

Implements Force.

int getNumTorsions ( ) const

inline

Get the number of Ryckaert-Bellemans torsion terms in the potential function.

void getTorsionParameters	(	int	index,
		int &	particle1,
		int &	particle2,
		int &	particle3,
		int &	particle4,
		double &	c0,
		double &	c1,
		double &	c2,
		double &	c3,
		double &	c4,
		double &	c5
	)		const

Get the force field parameters for a Ryckaert-Bellemans torsion term.

Parameters

index	the index of the torsion for which to get parameters
particle1	the index of the first particle forming the torsion
particle2	the index of the second particle forming the torsion
particle3	the index of the third particle forming the torsion
particle4	the index of the fourth particle forming the torsion
c0	the coefficient of the constant term, measured in kJ/mol
c1	the coefficient of the 1st order term, measured in kJ/mol
c2	the coefficient of the 2nd order term, measured in kJ/mol
c3	the coefficient of the 3rd order term, measured in kJ/mol
c4	the coefficient of the 4th order term, measured in kJ/mol
c5	the coefficient of the 5th order term, measured in kJ/mol

void setTorsionParameters	(	int	index,
		int	particle1,
		int	particle2,
		int	particle3,
		int	particle4,
		double	c0,
		double	c1,
		double	c2,
		double	c3,
		double	c4,
		double	c5
	)

Set the force field parameters for a Ryckaert-Bellemans torsion term.

Parameters

index	the index of the torsion for which to set parameters
particle1	the index of the first particle forming the torsion
particle2	the index of the second particle forming the torsion
particle3	the index of the third particle forming the torsion
particle4	the index of the fourth particle forming the torsion
c0	the coefficient of the constant term, measured in kJ/mol
c1	the coefficient of the 1st order term, measured in kJ/mol
c2	the coefficient of the 2nd order term, measured in kJ/mol
c3	the coefficient of the 3rd order term, measured in kJ/mol
c4	the coefficient of the 4th order term, measured in kJ/mol
c5	the coefficient of the 5th order term, measured in kJ/mol

void updateParametersInContext ( Context & context )

Update the per-torsion parameters in a Context to match those stored in this Force object.

This method provides an efficient method to update certain parameters in an existing Context without needing to reinitialize it. Simply call setTorsionParameters() to modify this object's parameters, then call updateParametersInState() to copy them over to the Context.

The only information this method updates is the values of per-torsion parameters. The set of particles involved in a torsion cannot be changed, nor can new torsions be added.

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

RBTorsionForce.h

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation