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RPMDIntegrator Class Reference

This is an Integrator which simulates a System using ring polymer molecular dynamics (RPMD). More...

+ Inheritance diagram for RPMDIntegrator:

Public Member Functions

def getNumCopies
 getNumCopies(RPMDIntegrator self) -> int
 
def getTemperature
 getTemperature(RPMDIntegrator self) -> double
 
def setTemperature
 setTemperature(RPMDIntegrator self, double temp)
 
def getFriction
 getFriction(RPMDIntegrator self) -> double
 
def setFriction
 setFriction(RPMDIntegrator self, double coeff)
 
def getRandomNumberSeed
 getRandomNumberSeed(RPMDIntegrator self) -> int
 
def setRandomNumberSeed
 setRandomNumberSeed(RPMDIntegrator self, int seed)
 
def setPositions
 setPositions(RPMDIntegrator self, int copy, std::vector< Vec3,std::allocator< Vec3 > > const & positions)
 
def setVelocities
 setVelocities(RPMDIntegrator self, int copy, std::vector< Vec3,std::allocator< Vec3 > > const & velocities)
 
def step
 step(RPMDIntegrator self, int steps)
 
def getState
 getState(self, copy, getPositions = False, getVelocities = False, getForces = False, getEnergy = False, getParameters = False, enforcePeriodicBox = False, groups = -1) -> State
 
def __init__
 init(OpenMM::RPMDIntegrator self, int numCopies, double temperature, double frictionCoeff, double stepSize) -> RPMDIntegrator init(OpenMM::RPMDIntegrator self, RPMDIntegrator other) -> RPMDIntegrator
 
def __del__
 del(OpenMM::RPMDIntegrator self)
 
- Public Member Functions inherited from Integrator
def __init__
 
def __del__
 del(OpenMM::Integrator self)
 
def getStepSize
 getStepSize(Integrator self) -> double
 
def setStepSize
 setStepSize(Integrator self, double size)
 
def getConstraintTolerance
 getConstraintTolerance(Integrator self) -> double
 
def setConstraintTolerance
 setConstraintTolerance(Integrator self, double tol)
 
def step
 step(Integrator self, int steps)
 

Public Attributes

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Detailed Description

This is an Integrator which simulates a System using ring polymer molecular dynamics (RPMD).

It simulates many copies of the System, with successive copies connected by harmonic springs to form a ring. This allows certain quantum mechanical effects to be efficiently simulated.

Because this Integrator simulates many copies of the System at once, it must be used differently from other Integrators. Instead of setting positions and velocities by calling methods of the Context, you should use the corresponding methods of the Integrator to set them for specific copies of the System. Similarly, you should retrieve state information for particular copies by calling getState() on the Integrator. Do not query the Context for state information.

Constructor & Destructor Documentation

def __init__ (   self,
  args 
)

init(OpenMM::RPMDIntegrator self, int numCopies, double temperature, double frictionCoeff, double stepSize) -> RPMDIntegrator init(OpenMM::RPMDIntegrator self, RPMDIntegrator other) -> RPMDIntegrator

Create a RPMDIntegrator.

Parameters
numCopiesthe number of copies of the system that should be simulated
temperaturethe temperature of the heat bath (in Kelvin)
frictionCoeffthe friction coefficient which couples the system to the heat bath (in inverse picoseconds)
stepSizethe step size with which to integrator the system (in picoseconds)
def __del__ (   self)

del(OpenMM::RPMDIntegrator self)

Member Function Documentation

def getFriction (   self)

getFriction(RPMDIntegrator self) -> double

Get the friction coefficient which determines how strongly the system is coupled to the heat bath (in inverse ps).

def getNumCopies (   self)

getNumCopies(RPMDIntegrator self) -> int

Get the number of copies of the system being simulated.

def getRandomNumberSeed (   self)

getRandomNumberSeed(RPMDIntegrator self) -> int

Get the random number seed. See setRandomNumberSeed() for details.

def getState (   self,
  copy,
  getPositions = False,
  getVelocities = False,
  getForces = False,
  getEnergy = False,
  getParameters = False,
  enforcePeriodicBox = False,
  groups = -1 
)

getState(self, copy, getPositions = False, getVelocities = False, getForces = False, getEnergy = False, getParameters = False, enforcePeriodicBox = False, groups = -1) -> State

Get a State object recording the current state information about one copy of the system.

Parameters
copy(int) the index of the copy for which to retrieve state information
getPositions(bool=False) whether to store particle positions in the State
getVelocities(bool=False) whether to store particle velocities in the State
getForces(bool=False) whether to store the forces acting on particles in the State
getEnergy(bool=False) whether to store potential and kinetic energy in the State
getParameter(bool=False) whether to store context parameters in the State
enforcePeriodicBox(bool=False) if false, the position of each particle will be whatever position is stored in the Context, regardless of periodic boundary conditions. If true, particle positions will be translated so the center of every molecule lies in the same periodic box.
groups(int=-1) a set of bit flags for which force groups to include when computing forces and energies. Group i will be included if (groups&(1<<i)) != 0. The default value includes all groups.
def getTemperature (   self)

getTemperature(RPMDIntegrator self) -> double

Get the temperature of the heat bath (in Kelvin).

def setFriction (   self,
  args 
)

setFriction(RPMDIntegrator self, double coeff)

Set the friction coefficient which determines how strongly the system is coupled to the heat bath (in inverse ps).

Parameters
coeffthe friction coefficient, measured in 1/ps
def setPositions (   self,
  args 
)

setPositions(RPMDIntegrator self, int copy, std::vector< Vec3,std::allocator< Vec3 > > const & positions)

Set the positions of all particles in one copy of the system.

Parameters
copythe index of the copy for which to set positions
positionsthe positions of all particles in the system
def setRandomNumberSeed (   self,
  args 
)

setRandomNumberSeed(RPMDIntegrator self, int seed)

Set the random number seed. The precise meaning of this parameter is undefined, and is left up to each Platform to interpret in an appropriate way. It is guaranteed that if two simulations are run with different random number seeds, the sequence of random forces will be different. On the other hand, no guarantees are made about the behavior of simulations that use the same seed. In particular, Platforms are permitted to use non-deterministic algorithms which produce different results on successive runs, even if those runs were initialized identically.

def setTemperature (   self,
  args 
)

setTemperature(RPMDIntegrator self, double temp)

Set the temperature of the heat bath (in Kelvin).

Parameters
tempthe temperature of the heat bath, measured in Kelvin
def setVelocities (   self,
  args 
)

setVelocities(RPMDIntegrator self, int copy, std::vector< Vec3,std::allocator< Vec3 > > const & velocities)

Get the velocities of all particles in one copy of the system.

Parameters
copythe index of the copy for which to set velocities
velocitiesthe velocities of all particles in the system
def step (   self,
  args 
)

step(RPMDIntegrator self, int steps)

Advance a simulation through time by taking a series of time steps.

Parameters
stepsthe number of time steps to take

Member Data Documentation

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