PeriodicTorsionForce Class Reference

This class implements an interaction between groups of four particles that varies periodically with the torsion angle between them. More...

#include <PeriodicTorsionForce.h>

Inheritance diagram for PeriodicTorsionForce:

List of all members.

Classes
class	PeriodicTorsionInfo
	This is an internal class used to record information about a torsion.
Public Member Functions
	PeriodicTorsionForce ()
	Create a PeriodicTorsionForce.
int	getNumTorsions () const
	Get the number of periodic torsion terms in the potential function.
int	addTorsion (int particle1, int particle2, int particle3, int particle4, int periodicity, double phase, double k)
	Add a periodic torsion term to the force field.
void	getTorsionParameters (int index, int &particle1, int &particle2, int &particle3, int &particle4, int &periodicity, double &phase, double &k) const
	Get the force field parameters for a periodic torsion term.
void	setTorsionParameters (int index, int particle1, int particle2, int particle3, int particle4, int periodicity, double phase, double k)
	Set the force field parameters for a periodic torsion term.
Protected Member Functions
ForceImpl *	createImpl ()
	When a Context is created, it invokes this method on each Force in the System.

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Detailed Description

This class implements an interaction between groups of four particles that varies periodically with the torsion angle between them.

To use it, create a PeriodicTorsionForce object then call addTorsion() once for each torsion. After a torsion has been added, you can modify its force field parameters by calling setTorsionParameters().

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Constructor & Destructor Documentation

PeriodicTorsionForce

(

)

Create a PeriodicTorsionForce.

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Member Function Documentation

int addTorsion	(	int	particle1,
		int	particle2,
		int	particle3,
		int	particle4,
		int	periodicity,
		double	phase,
		double	k
	)

Add a periodic 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
	particle3	the index of the fourth particle forming the torsion
	periodicity	the periodicity of the torsion
	phase	the phase offset of the torsion, measured in radians
	k	the force constant for the torsion

Returns:

the index of the torsion that was added

ForceImpl* createImpl

(

)

[protected, virtual]

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 periodic torsion terms in the potential function.

void getTorsionParameters	(	int	index,
		int &	particle1,
		int &	particle2,
		int &	particle3,
		int &	particle4,
		int &	periodicity,
		double &	phase,
		double &	k
	)			const

Get the force field parameters for a periodic 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
	particle3	the index of the fourth particle forming the torsion
	periodicity	the periodicity of the torsion
	phase	the phase offset of the torsion, measured in radians
	k	the force constant for the torsion

void setTorsionParameters	(	int	index,
		int	particle1,
		int	particle2,
		int	particle3,
		int	particle4,
		int	periodicity,
		double	phase,
		double	k
	)

Set the force field parameters for a periodic 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
	particle3	the index of the fourth particle forming the torsion
	periodicity	the periodicity of the torsion
	phase	the phase offset of the torsion, measured in radians
	k	the force constant for the torsion

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

• PeriodicTorsionForce.h