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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

ForceImplcreateImpl () const
 When a Context is created, it invokes this method on each Force in the System.
 
- Protected Member Functions inherited from Force
ForceImplgetImplInContext (Context &context)
 Get the ForceImpl corresponding to this Force in a Context.
 
ContextImplgetContextImpl (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

Member Function Documentation

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

Add a bond term to the force field.

Parameters
particle1the index of the first particle connected by the bond
particle2the index of the second particle connected by the bond
lengththe equilibrium length of the bond, measured in nm
kthe 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
indexthe index of the bond for which to get parameters
particle1the index of the first particle connected by the bond
particle2the index of the second particle connected by the bond
lengththe equilibrium length of the bond, measured in nm
kthe 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
indexthe index of the bond for which to set parameters
particle1the index of the first particle connected by the bond
particle2the index of the second particle connected by the bond
lengththe equilibrium length of the bond, measured in nm
kthe 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.


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