Evolver Class

The Evolver class stands as a central component in the design and implementation of the PyMembrane framework. Its primary role is to oversee the dynamics of the simulated system. To achieve this, the Evolver class maintains a comprehensive list of Forces, Integrators, Minimizers, and Constraints.

By capturing the essence of system dynamics through these elements, Evolver ensures that the behavior of the System. The Evolver class is a key part of PyMembrane in short:

1. It keeps track of Forces, Integrators, Minimizers, and Constraints.

2. It controls how the system changes over time by applying forces, integrators, minimizers, and constraints.

Creating an evolver class

import pymembrane as mb
# create a new system instance
system = mb.System()
vertex_file = 'hexagon_vertices.inp'
face_file = 'hexagon_faces.inp'
system.read_mesh_from_files(files={'vertices':vertex_file, 'faces':face_file})

# create the evolver class
evolver = mb.Evolver(system)

The Python interface of the Evolver class define the following methods that the user needs to get familiar with:

Evolver methods

Main methods

• add_force(…)

  1. add_force(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: str, arg1: Dict[str, Dict[str, str]]) -> None
     

  2. add_force(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: str, arg1: Dict[str, Dict[Tuple[str, str], str]]) -> None
     

• delete_force(…): delete force method

  delete_force(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: str) -> None
  

• add_integrator(…):

  add_integrator(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: str, arg1: Dict[str, str]) -> None
  

• delete_integrator(…): delete integrator method

  delete_integrator(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: str) -> None
  

• add_constraint(…): add constraint method

  add_constraint(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: str, arg1: Dict[str, str]) -> None
  

• delete_constraint(…): delete constraint method

  delete_constraint(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: str) -> None
  

• set(…): set/modify properties for integrators/forces/minimizers/constraints

  1. set(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: str, arg1: Dict[str, Dict[Tuple[str, str], str]]) -> None
     

  2. set(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: str, arg1: Dict[str, Dict[str, str]]) -> None
     

  3. set(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: str, arg1: Dict[str, str]) -> None
     

Temperature and time methods

In addition to the methods defined above, the Evolver class also provides a way to propagate important information into the all of the integrators at once. The latter is important when more than one integrators is present in the system. In the same way for molecular dynamics the time step needs to be set globally.

• set_global_temperature(…): set the temperature in the whole system

  set_global_temperature(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: str) -> None
  

• set_time_step(…): set the time step for Molecular Dynamics methods

  set_time_step(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: str) -> None
  

Dynamics methods

As we mentioned earlier, the Evolver class is responsible for the dynamics of the system. The following methods are used to propagate the system forward in time.

• evolveMC(…): Evolve the mesh following Monte Carlos methods loaded. Arg: steps Return: accepted moves

  evolveMC(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: int) -> int
  

• evolveMD(…): evolve the mesh following Molecular Dynamics methods loaded

  evolveMD(self: pymembrane.cppmodule.cppmodule.Evolver, arg0: int) -> None
  

• enforce_mesh_constraints(…): enforce constraint method

  enforce_mesh_constraints(self: pymembrane.cppmodule.cppmodule.Evolver) -> None
  

Other methods

Other methods that are not required to be used by the user are unless debugging or testing, for example, the following methods are used to compute the mesh energy and forces.

• compute_mesh_energy(…): compute the mesh energy and store in the mesh

  compute_mesh_energy(self: pymembrane.cppmodule.cppmodule.Evolver) -> None
  

• compute_mesh_forces(…): compute the mesh forces and store in the mesh

  compute_mesh_forces(self: pymembrane.cppmodule.cppmodule.Evolver) -> None
  

• reset_mesh_energy(…): reset the mesh energy

  reset_mesh_energy(self: pymembrane.cppmodule.cppmodule.Evolver) -> None
  

• reset_mesh_forces(…): reset the mesh forces

  reset_mesh_forces(self: pymembrane.cppmodule.cppmodule.Evolver) -> None
  

To know more about the Evolver class, please refer to contextual help in python:

help(Evolver)