import nengo
from nengo.exceptions import ObsoleteError
[docs]class Oscillator(nengo.Network):
"""A two-dimensional ensemble with interacting recurrent connections.
The ensemble connects to itself in a manner similar to the integrator;
however, here the two dimensions interact with each other to implement
a cyclic oscillator.
Parameters
----------
recurrent_tau : float
Time constant on the recurrent connection.
frequency : float
Desired frequency, in Hz, of the cyclic oscillation.
n_neurons : int
Number of neurons in the recurrently connected ensemble.
**kwargs
Keyword arguments passed through to ``nengo.Network``
like 'label' and 'seed'.
Attributes
----------
ensemble : Ensemble
The recurrently connected oscillatory ensemble.
input : Node
Provides the input signal.
"""
def __init__(self, recurrent_tau, frequency, n_neurons, **kwargs):
if "net" in kwargs:
raise ObsoleteError("The 'net' argument is no longer supported.")
kwargs.setdefault("label", "Oscillator")
super().__init__(**kwargs)
with self:
self.input = nengo.Node(label="In", size_in=2)
self.ensemble = nengo.Ensemble(n_neurons, dimensions=2, label="Oscillator")
tA = [[1, -frequency * recurrent_tau], [frequency * recurrent_tau, 1]]
nengo.Connection(
self.ensemble, self.ensemble, synapse=recurrent_tau, transform=tA
)
nengo.Connection(self.input, self.ensemble, synapse=None)
self.output = self.ensemble
