HarmonicBondForce Class Reference

This class implements an interaction between pairs of particles that varies harmonically with the distance between them. More...

#include <HarmonicBondForce.h>

Inheritance diagram for HarmonicBondForce:

Public Member Functions
	HarmonicBondForce ()
	Create a HarmonicBondForce.
int	getNumBonds () const
	Get the number of harmonic bond stretch terms in the potential function.
int	addBond (int particle1, int particle2, double length, double k)
	Add a bond term to the force field.
void	getBondParameters (int index, int &particle1, int &particle2, double &length, double &k) const
	Get the force field parameters for a bond term.
void	setBondParameters (int index, int particle1, int particle2, double length, double k)
	Set the force field parameters for a bond term.
void	updateParametersInContext (Context &context)
	Update the per-bond 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 () const
	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 pairs of particles that varies harmonically with the distance between them.

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

Constructor & Destructor Documentation

HarmonicBondForce

(

)

Create a HarmonicBondForce.

Member Function Documentation

int addBond	(	int	particle1,
		int	particle2,
		double	length,
		double	k
	)

Add a bond term to the force field.

Parameters

particle1	the index of the first particle connected by the bond
particle2	the index of the second particle connected by the bond
length	the equilibrium length of the bond, measured in nm
k	the harmonic force constant for the bond, measured in kJ/mol/nm^2

Returns

the index of the bond that was added

ForceImpl* createImpl ( ) const

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.

void getBondParameters	(	int	index,
		int &	particle1,
		int &	particle2,
		double &	length,
		double &	k
	)		const

Get the force field parameters for a bond term.

Parameters

index	the index of the bond for which to get parameters
particle1	the index of the first particle connected by the bond
particle2	the index of the second particle connected by the bond
length	the equilibrium length of the bond, measured in nm
k	the harmonic force constant for the bond, measured in kJ/mol/nm^2

int getNumBonds ( ) const

inline

Get the number of harmonic bond stretch terms in the potential function.

void setBondParameters	(	int	index,
		int	particle1,
		int	particle2,
		double	length,
		double	k
	)

Set the force field parameters for a bond term.

Parameters

index	the index of the bond for which to set parameters
particle1	the index of the first particle connected by the bond
particle2	the index of the second particle connected by the bond
length	the equilibrium length of the bond, measured in nm
k	the harmonic force constant for the bond, measured in kJ/mol/nm^2

void updateParametersInContext

(

Context &

context

)

Update the per-bond 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 setBondParameters() 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-bond parameters. The set of particles involved in a bond cannot be changed, nor can new bonds be added.

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

• HarmonicBondForce.h