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from copy import copy
import warnings
import numpy as np
import nengo
from nengo.config import SupportDefaultsMixin
from nengo.exceptions import NotAddedToNetworkWarning, ValidationError
from nengo.params import (
FrozenObject,
IntParam,
iter_params,
NumberParam,
Parameter,
StringParam,
Unconfigurable,
)
from nengo.utils.numpy import as_shape, maxint, maxseed, is_integer
class NetworkMember(type):
"""A metaclass used to add instances of derived classes to networks.
Inheriting from this class means that Network.add will be invoked after
initializing the object, unless add_to_container=False is passed to the
derived class constructor.
"""
def __call__(cls, *args, **kwargs):
"""Override default __call__ behavior so that Network.add is called."""
inst = cls.__new__(cls)
add_to_container = kwargs.pop("add_to_container", True)
# Do the __init__ before adding in case __init__ errors out
inst.__init__(*args, **kwargs)
if add_to_container:
nengo.Network.add(inst)
inst._initialized = True
return inst
class NengoObject(SupportDefaultsMixin, metaclass=NetworkMember):
"""A base class for Nengo objects.
Parameters
----------
label : string
A descriptive label for the object.
seed : int
The seed used for random number generation.
Attributes
----------
label : string
A descriptive label for the object.
seed : int
The seed used for random number generation.
"""
# Order in which parameters have to be initialized.
# Missing parameters will be initialized last in an undefined order.
# This is needed for pickling and copying of Nengo objects when the
# parameter initialization order matters.
_param_init_order = []
label = StringParam("label", default=None, optional=True)
seed = IntParam("seed", default=None, low=0, high=maxseed, optional=True)
def __init__(self, label, seed):
super().__init__()
self._initialized = False
self.label = label
self.seed = seed
def __getstate__(self):
state = self.__dict__.copy()
state["_initialized"] = False
for attr in self.params:
param = getattr(type(self), attr)
if self in param:
state[attr] = getattr(self, attr)
return state
def __setstate__(self, state):
for attr in self._param_init_order:
setattr(self, attr, state.pop(attr))
for attr in self.params:
if attr in state:
setattr(self, attr, state.pop(attr))
for k, v in state.items():
setattr(self, k, v)
self._initialized = True
if len(nengo.Network.context) > 0:
warnings.warn(NotAddedToNetworkWarning(self))
def __setattr__(self, name, val):
initialized = hasattr(self, "_initialized") and self._initialized
if initialized and not hasattr(self, name):
warnings.warn(
"Creating new attribute '%s' on '%s'. "
"Did you mean to change an existing attribute?" % (name, self),
SyntaxWarning,
)
super().__setattr__(name, val)
def __str__(self):
return self._str(include_id=not hasattr(self, "label") or self.label is None)
def __repr__(self):
return self._str(include_id=True)
def _str(self, include_id):
return "<%s%s%s>" % (
type(self).__name__,
""
if not hasattr(self, "label")
else " (unlabeled)"
if self.label is None
else ' "%s"' % self.label,
" at 0x%x" % id(self) if include_id else "",
)
@property
def params(self):
"""Returns a list of parameter names that can be set."""
return list(iter_params(self))
def copy(self, add_to_container=True):
with warnings.catch_warnings():
# We warn when copying since we can't change add_to_container.
# However, we deal with it here, so we ignore the warning.
warnings.simplefilter("ignore", category=NotAddedToNetworkWarning)
c = copy(self)
if add_to_container:
nengo.Network.add(c)
return c
class ObjView:
"""Container for a slice with respect to some object.
This is used by the __getitem__ of Neurons, Node, and Ensemble, in order
to pass slices of those objects to Connection. This is a notational
convenience for creating transforms. See Connection for details.
Does not currently support any other view-like operations.
"""
def __init__(self, obj, key=slice(None)):
self.obj = obj
# Node.size_in != size_out, so one of these can be invalid
# NumPy <= 1.8 raises a ValueError instead of an IndexError.
try:
self.size_in = np.arange(self.obj.size_in)[key].size
except (IndexError, ValueError):
self.size_in = None
try:
self.size_out = np.arange(self.obj.size_out)[key].size
except (IndexError, ValueError):
self.size_out = None
if self.size_in is None and self.size_out is None:
raise IndexError("Invalid slice '%s' of %s" % (key, self.obj))
if is_integer(key):
# single slices of the form [i] should be cast into
# slice objects for convenience
if key == -1:
# special case because slice(-1, 0) gives the empty list
self.slice = slice(key, None)
else:
self.slice = slice(key, key + 1)
else:
self.slice = key
def copy(self):
return copy(self)
def __len__(self):
return self.size_out
def __str__(self):
return "%s[%s]" % (self.obj, self._slice_string)
def __repr__(self):
return "%r[%s]" % (self.obj, self._slice_string)
@property
def _slice_string(self):
if isinstance(self.slice, slice):
sl_start = "" if self.slice.start is None else self.slice.start
sl_stop = "" if self.slice.stop is None else self.slice.stop
if self.slice.step is None:
return "%s:%s" % (sl_start, sl_stop)
else:
return "%s:%s:%s" % (sl_start, sl_stop, self.slice.step)
else:
return str(self.slice)
class NengoObjectParam(Parameter):
def __init__(
self,
name,
optional=False,
readonly=True,
nonzero_size_in=False,
nonzero_size_out=False,
):
default = Unconfigurable # These can't have defaults
self.nonzero_size_in = nonzero_size_in
self.nonzero_size_out = nonzero_size_out
super().__init__(name, default, optional, readonly)
def coerce(self, instance, nengo_obj):
nengo_objects = (
NengoObject,
ObjView,
nengo.ensemble.Neurons,
nengo.connection.LearningRule,
)
if not isinstance(nengo_obj, nengo_objects):
raise ValidationError(
"'%s' is not a Nengo object" % nengo_obj, attr=self.name, obj=instance
)
if self.nonzero_size_in and nengo_obj.size_in < 1:
raise ValidationError(
"'%s' must have size_in > 0." % nengo_obj, attr=self.name, obj=instance
)
if self.nonzero_size_out and nengo_obj.size_out < 1:
raise ValidationError(
"'%s' must have size_out > 0." % nengo_obj, attr=self.name, obj=instance
)
return super().coerce(instance, nengo_obj)
class Process(FrozenObject):
"""A general system with input, output, and state.
For more details on how to use processes and make
custom process subclasses, see :doc:`examples/advanced/processes`.
Parameters
----------
default_size_in : int
Sets the default size in for nodes using this process.
default_size_out : int
Sets the default size out for nodes running this process. Also,
if ``d`` is not specified in `~.Process.run` or `~.Process.run_steps`,
this will be used.
default_dt : float
If ``dt`` is not specified in `~.Process.run`, `~.Process.run_steps`,
`~.Process.ntrange`, or `~.Process.trange`, this will be used.
seed : int, optional
Random number seed. Ensures random factors will be the same each run.
Attributes
----------
default_dt : float
If ``dt`` is not specified in `~.Process.run`, `~.Process.run_steps`,
`~.Process.ntrange`, or `~.Process.trange`, this will be used.
default_size_in : int
The default size in for nodes using this process.
default_size_out : int
The default size out for nodes running this process. Also, if ``d`` is
not specified in `~.Process.run` or `~.Process.run_steps`,
this will be used.
seed : int or None
Random number seed. Ensures random factors will be the same each run.
"""
default_size_in = IntParam("default_size_in", low=0)
default_size_out = IntParam("default_size_out", low=0)
default_dt = NumberParam("default_dt", low=0, low_open=True)
seed = IntParam("seed", low=0, high=maxseed, optional=True)
def __init__(
self, default_size_in=0, default_size_out=1, default_dt=0.001, seed=None
):
super().__init__()
self.default_size_in = default_size_in
self.default_size_out = default_size_out
self.default_dt = default_dt
self.seed = seed
def apply(self, x, d=None, dt=None, rng=np.random, copy=True, **kwargs):
"""Run process on a given input.
Keyword arguments that do not appear in the parameter list below
will be passed to the ``make_step`` function of this process.
Parameters
----------
x : ndarray
The input signal given to the process.
d : int, optional
Output dimensionality. If None, ``default_size_out`` will be used.
dt : float, optional
Simulation timestep. If None, ``default_dt`` will be used.
rng : `numpy.random.mtrand.RandomState`
Random number generator used for stochstic processes.
copy : bool, optional
If True, a new output array will be created for output.
If False, the input signal ``x`` will be overwritten.
"""
shape_in = as_shape(np.asarray(x[0]).shape, min_dim=1)
shape_out = as_shape(self.default_size_out if d is None else d)
dt = self.default_dt if dt is None else dt
rng = self.get_rng(rng)
state = self.make_state(shape_in, shape_out, dt)
step = self.make_step(shape_in, shape_out, dt, rng, state, **kwargs)
output = np.zeros((len(x),) + shape_out) if copy else x
for i, xi in enumerate(x):
output[i] = step((i + 1) * dt, xi)
return output
def get_rng(self, rng):
"""Get a properly seeded independent RNG for the process step.
Parameters
----------
rng : `numpy.random.mtrand.RandomState`
The parent random number generator to use if the seed is not set.
"""
seed = rng.randint(maxint) if self.seed is None else self.seed
return np.random.RandomState(seed)
def make_state(self, shape_in, shape_out, dt, dtype=None):
"""Get a dictionary of signals to represent the state of this process.
The builder uses this to allocate memory for the process state, so
that the state can be represented as part of the whole simulator state.
.. versionadded:: 3.0.0
Parameters
----------
shape_in : tuple
The shape of the input signal.
shape_out : tuple
The shape of the output signal.
dt : float
The simulation timestep.
dtype : `numpy.dtype`
The data type requested by the builder. If `None`, then this
function is free to choose the best type for the signals involved.
Returns
-------
initial_state : {string: `numpy.ndarray`}
A dictionary mapping keys to arrays containing the initial state
values. The keys will be used to identify the signals in
`.Process.make_step`.
"""
return {} # Implement if the process has a state
def make_step(self, shape_in, shape_out, dt, rng, state):
"""Create function that advances the process forward one time step.
This must be implemented by all custom processes. The parameters below
indicate what information is provided by the builder.
Parameters
----------
shape_in : tuple
The shape of the input signal.
shape_out : tuple
The shape of the output signal.
dt : float
The simulation timestep.
rng : `numpy.random.mtrand.RandomState`
A random number generator.
state : {string: `numpy.ndarray`}
A dictionary mapping keys to signals, where the signals fully
represent the state of the process. The signals are initialized
by `.Process.make_state`.
.. versionadded:: 3.0.0
"""
raise NotImplementedError("Process must implement `make_step` method.")
def run(self, t, d=None, dt=None, rng=np.random, **kwargs):
"""Run process without input for given length of time.
Keyword arguments that do not appear in the parameter list below
will be passed to the ``make_step`` function of this process.
Parameters
----------
t : float
The length of time to run.
d : int, optional
Output dimensionality. If None, ``default_size_out`` will be used.
dt : float, optional
Simulation timestep. If None, ``default_dt`` will be used.
rng : `numpy.random.mtrand.RandomState`
Random number generator used for stochstic processes.
"""
dt = self.default_dt if dt is None else dt
n_steps = int(np.round(float(t) / dt))
return self.run_steps(n_steps, d=d, dt=dt, rng=rng, **kwargs)
def run_steps(self, n_steps, d=None, dt=None, rng=np.random, **kwargs):
"""Run process without input for given number of steps.
Keyword arguments that do not appear in the parameter list below
will be passed to the ``make_step`` function of this process.
Parameters
----------
n_steps : int
The number of steps to run.
d : int, optional
Output dimensionality. If None, ``default_size_out`` will be used.
dt : float, optional
Simulation timestep. If None, ``default_dt`` will be used.
rng : `numpy.random.mtrand.RandomState`
Random number generator used for stochstic processes.
"""
shape_in = as_shape(0)
shape_out = as_shape(self.default_size_out if d is None else d)
dt = self.default_dt if dt is None else dt
rng = self.get_rng(rng)
state = self.make_state(shape_in, shape_out, dt)
step = self.make_step(shape_in, shape_out, dt, rng, state, **kwargs)
output = np.zeros((n_steps,) + shape_out)
for i in range(n_steps):
output[i] = step((i + 1) * dt)
return output
def ntrange(self, n_steps, dt=None):
"""Create time points corresponding to a given number of steps.
Parameters
----------
n_steps : int
The given number of steps.
dt : float, optional
Simulation timestep. If None, ``default_dt`` will be used.
"""
dt = self.default_dt if dt is None else dt
return dt * np.arange(1, n_steps + 1)
def trange(self, t, dt=None):
"""Create time points corresponding to a given length of time.
Parameters
----------
t : float
The given length of time.
dt : float, optional
Simulation timestep. If None, ``default_dt`` will be used.
"""
dt = self.default_dt if dt is None else dt
n_steps = int(np.round(float(t) / dt))
return self.ntrange(n_steps, dt=dt)
class ProcessParam(Parameter):
"""Must be a Process."""
def coerce(self, instance, process):
self.check_type(instance, process, Process)
return super().coerce(instance, process)
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