Source code for elastica.modules.damping

__doc__ = """

(added in version 0.3.0)

Provides the damper interface to apply damping
on the rods. (see ``).


from elastica.dissipation import DamperBase

[docs]class Damping: """ The Damping class is a module for applying damping on rod-like objects, the simulator class must be derived from Damping class. Attributes ---------- _dampers: list List of damper classes defined for rod-like objects. """ def __init__(self): self._dampers = [] super(Damping, self).__init__() self._feature_group_constrain_rates.append(self._dampen_rates) self._feature_group_finalize.append(self._finalize_dampers)
[docs] def dampen(self, system): """ This method applies damping on relevant user-defined system or rod-like object. You must input the system or rod-like object that you want to apply damping on. Parameters ---------- system: object System is a rod-like object. Returns ------- """ sys_idx = self._get_sys_idx_if_valid(system) # Create _Damper object, cache it and return to user _damper = _Damper(sys_idx) self._dampers.append(_damper) return _damper
def _finalize_dampers(self): # From stored _Damping objects, instantiate the dissipation/damping # inplace : self._dampers[:] = [ (, damper(self._systems[])) for damper in self._dampers ] # Sort from lowest id to highest id for potentially better memory access # _dampers contains list of tuples. First element of tuple is rod number and # following elements are the type of damping. # Thus using lambda we iterate over the list of tuples and use rod number (x[0]) # to sort dampers. self._dampers.sort(key=lambda x: x[0]) def _dampen_rates(self, time, *args, **kwargs): for sys_id, damper in self._dampers: damper.dampen_rates(self._systems[sys_id], time, *args, **kwargs)
class _Damper: """ Damper module private class Attributes ---------- _sys_idx: int _damper_cls: list *args Variable length argument list. **kwargs Arbitrary keyword arguments. """ def __init__(self, sys_idx: int): """ Parameters ---------- sys_idx: int """ self._sys_idx = sys_idx self._damper_cls = None self._args = () self._kwargs = {} def using(self, damper_cls, *args, **kwargs): """ This method is a module to set which damper class is used to enforce damping from user defined rod-like objects. Parameters ---------- damper_cls : object User defined damper class. *args Variable length argument list **kwargs Arbitrary keyword arguments. Returns ------- """ assert issubclass( damper_cls, DamperBase ), "{} is not a valid damper. Damper must be driven from DamperBase.".format( damper_cls ) self._damper_cls = damper_cls self._args = args self._kwargs = kwargs return self def id(self): return self._sys_idx def __call__(self, rod, *args, **kwargs): """Constructs a Damper class object after checks Parameters ---------- args kwargs Returns ------- """ if not self._damper_cls: raise RuntimeError( "No damper provided to dampen rod id {0} at {1}," "but damping was intended. Did you" "forget to call the `using` method?".format(, rod) ) try: damper = self._damper_cls(*self._args, _system=rod, **self._kwargs) return damper except (TypeError, IndexError): raise TypeError("Unable to construct damping class.\n")