PeriodicTorsionForce Class Reference

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

Inheritance diagram for PeriodicTorsionForce:

Public Member Functions
def	getNumTorsions
	getNumTorsions(PeriodicTorsionForce self) -> int More...
def	addTorsion
	addTorsion(PeriodicTorsionForce self, int particle1, int particle2, int particle3, int particle4, int periodicity, double phase, double k) -> int More...
def	getTorsionParameters
	getTorsionParameters(PeriodicTorsionForce self, int index) More...
def	setTorsionParameters
	setTorsionParameters(PeriodicTorsionForce self, int index, int particle1, int particle2, int particle3, int particle4, int periodicity, double phase, double k) More...
def	updateParametersInContext
	updateParametersInContext(PeriodicTorsionForce self, Context context) More...
def	usesPeriodicBoundaryConditions
	usesPeriodicBoundaryConditions(PeriodicTorsionForce self) -> bool More...
def	__init__
	init(OpenMM::PeriodicTorsionForce self) -> PeriodicTorsionForce init(OpenMM::PeriodicTorsionForce self, PeriodicTorsionForce other) -> PeriodicTorsionForce More...
def	__del__
	del(OpenMM::PeriodicTorsionForce self) More...
Public Member Functions inherited from Force
def	__init__
def	__del__
	del(OpenMM::Force self) More...
def	getForceGroup
	getForceGroup(Force self) -> int More...
def	setForceGroup
	setForceGroup(Force self, int group) More...
def	usesPeriodicBoundaryConditions
	usesPeriodicBoundaryConditions(Force self) -> bool More...
def	__copy__
def	__deepcopy__

Public Attributes
	this

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(). This will have no effect on Contexts that already exist unless you call updateParametersInContext().

Constructor & Destructor Documentation

def __init__	(		self,
			args
	)

init(OpenMM::PeriodicTorsionForce self) -> PeriodicTorsionForce init(OpenMM::PeriodicTorsionForce self, PeriodicTorsionForce other) -> PeriodicTorsionForce

Create a PeriodicTorsionForce.

References simtk.openmm.openmm.stripUnits().

def __del__

(

self

)

del(OpenMM::PeriodicTorsionForce self)

References simtk.openmm.openmm.stripUnits().

Member Function Documentation

def addTorsion	(		self,
			args
	)

addTorsion(PeriodicTorsionForce self, int particle1, int particle2, int particle3, int particle4, int periodicity, double phase, double k) -> int

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
particle4	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

References simtk.openmm.openmm.stripUnits().

def getNumTorsions	(		self,
			args
	)

getNumTorsions(PeriodicTorsionForce self) -> int

Get the number of periodic torsion terms in the potential function

References simtk.openmm.openmm.stripUnits().

def getTorsionParameters	(		self,
			args
	)

getTorsionParameters(PeriodicTorsionForce self, int index)

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
particle4	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

References simtk.openmm.openmm.stripUnits().

def setTorsionParameters	(		self,
			args
	)

setTorsionParameters(PeriodicTorsionForce self, 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
particle4	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

References simtk.openmm.openmm.stripUnits().

def updateParametersInContext	(		self,
			args
	)

updateParametersInContext(PeriodicTorsionForce self, 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 updateParametersInContext() 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.

References simtk.openmm.openmm.stripUnits().

def usesPeriodicBoundaryConditions	(		self,
			args
	)

usesPeriodicBoundaryConditions(PeriodicTorsionForce self) -> bool

Returns whether or not this force makes use of periodic boundary conditions.

References simtk.openmm.openmm.stripUnits().

Member Data Documentation

this

---

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

• openmm.py