espressopp.integrator.VelocityVerletRESPA¶
This is a multiple time stepping integrator according to the RESPA scheme (J. Chem. Phys. 97, 1990 (1992)). It has two layers: All forces of type “NonbondedSlow” are updated with a frequency given by the long time step, while all other forces are calculated according to the short time step. The short time step can be defined and set as a property of the integrator object, while the long time step is given by the product of the short time step with an integer “multistep”, which can also be set.
Example:
>>> integrator = espressopp.integrator.VelocityVerletRESPA(system)
>>> integrator.dt = timestep
>>> integrator.multistep = multistep
>>> ...
>>> integrator.run(nsteps)

class
espressopp.integrator.
VelocityVerletRESPA
(system)¶ Constructs the VelocityVerletRESPA object.
Parameters: system (shared_ptr<System>) – system object

espressopp.integrator.VelocityVerletRESPA.
setmultistep
(multistep)¶ Sets the multiplier to construct the large timestep by multiplication with short time step as long_timestep = multistep * dt
Parameters: multistep – multiplier to construct the large timestep by multiplication with short time step

espressopp.integrator.VelocityVerletRESPA.
getmultistep
()¶ Gets the multiplier to construct the long timestep by multiplication with short time step as long_timestep = multistep * dt
Returns: multiplier to construct the long timestep by multiplication with short time step Return type: int

int espressopp.integrator.VelocityVerletRESPA.multistep
Multiplier to construct the long timestep by multiplication with short time step as long_timestep = multistep * dt

real espressopp.integrator.VelocityVerletRESPA.dt
The short time step