def test_signaldict():
    """Tests SignalDict's dict overrides."""
    signaldict = SignalDict()

    scalar = Signal(1.)

    # Both __getitem__ and __setitem__ raise KeyError
    with pytest.raises(KeyError):
        signaldict[scalar]
    with pytest.raises(KeyError):
        signaldict[scalar] = np.array(1.)

    signaldict.init(scalar)
    assert np.allclose(signaldict[scalar], np.array(1.))
    # __getitem__ handles scalars
    assert signaldict[scalar].shape == ()

    one_d = Signal([1.])
    signaldict.init(one_d)
    assert np.allclose(signaldict[one_d], np.array([1.]))
    assert signaldict[one_d].shape == (1,)

    two_d = Signal([[1.], [1.]])
    signaldict.init(two_d)
    assert np.allclose(signaldict[two_d], np.array([[1.], [1.]]))
    assert signaldict[two_d].shape == (2, 1)

    # __getitem__ handles views
    two_d_view = two_d[0, :]
    signaldict.init(two_d_view)
    assert np.allclose(signaldict[two_d_view], np.array([1.]))
    assert signaldict[two_d_view].shape == (1,)

    # __setitem__ ensures memory location stays the same
    memloc = signaldict[scalar].__array_interface__['data'][0]
    signaldict[scalar] = np.array(0.)
    assert np.allclose(signaldict[scalar], np.array(0.))
    assert signaldict[scalar].__array_interface__['data'][0] == memloc

    memloc = signaldict[one_d].__array_interface__['data'][0]
    signaldict[one_d] = np.array([0.])
    assert np.allclose(signaldict[one_d], np.array([0.]))
    assert signaldict[one_d].__array_interface__['data'][0] == memloc

    memloc = signaldict[two_d].__array_interface__['data'][0]
    signaldict[two_d] = np.array([[0.], [0.]])
    assert np.allclose(signaldict[two_d], np.array([[0.], [0.]]))
    assert signaldict[two_d].__array_interface__['data'][0] == memloc

    # __str__ pretty-prints signals and current values
    # Order not guaranteed for dicts, so we have to loop
    for k in signaldict:
        assert "%s %s" % (repr(k), repr(signaldict[k])) in str(signaldict)

    def __init__(self, network, dt=0.001, seed=None, model=None):
        self.closed = False

        if model is None:
            dt = float(dt)  # make sure it's a float (for division purposes)
            self.model = Model(dt=dt,
                               label="%s, dt=%f" % (network, dt),
                               decoder_cache=get_default_decoder_cache())
        else:
            self.model = model

        if network is not None:
            # Build the network into the model
            self.model.build(network)

        self.model.decoder_cache.shrink()

        # -- map from Signal.base -> ndarray
        self.signals = SignalDict()
        for op in self.model.operators:
            op.init_signals(self.signals)

        # Order the steps (they are made in `Simulator.reset`)
        self.dg = operator_depencency_graph(self.model.operators)
        self._step_order = [op for op in toposort(self.dg)
                            if hasattr(op, 'make_step')]

        # Add built states to the probe dictionary
        self._probe_outputs = self.model.params

        # Provide a nicer interface to probe outputs
        self.data = ProbeDict(self._probe_outputs)

        seed = np.random.randint(npext.maxint) if seed is None else seed
        self.reset(seed=seed)

def test_signal_reshape():
    """Tests Signal.reshape"""
    # check proper shape after reshape
    three_d = Signal(np.ones((2, 2, 2)))
    assert three_d.reshape((8,)).shape == (8,)
    assert three_d.reshape((4, 2)).shape == (4, 2)
    assert three_d.reshape((2, 4)).shape == (2, 4)
    assert three_d.reshape(-1).shape == (8,)
    assert three_d.reshape((4, -1)).shape == (4, 2)
    assert three_d.reshape((-1, 4)).shape == (2, 4)
    assert three_d.reshape((2, -1, 2)).shape == (2, 2, 2)
    assert three_d.reshape((1, 2, 1, 2, 2, 1)).shape == (1, 2, 1, 2, 2, 1)

    # check with non-contiguous arrays (and with offset)
    value = np.arange(20).reshape(5, 4)
    s = Signal(np.array(value), name='s')

    s0slice = slice(0, 3), slice(None, None, 2)
    s0shape = 2, 3
    s0 = s[s0slice].reshape(*s0shape)
    assert s.offset == 0
    assert np.array_equal(s0.initial_value, value[s0slice].reshape(*s0shape))

    s1slice = slice(1, None), slice(None, None, 2)
    s1shape = 2, 4
    s1 = s[s1slice].reshape(s1shape)
    assert s1.offset == 4 * s1.dtype.itemsize
    assert np.array_equal(s1.initial_value, value[s1slice].reshape(s1shape))

    # check error if non-contiguous array cannot be reshaped without copy
    s2slice = slice(None, None, 2), slice(None, None, 2)
    s2shape = 2, 3
    s2 = s[s2slice]
    with pytest.raises(SignalError):
        s2.reshape(s2shape)

    # check that views are working properly (incrementing `s` effects views)
    values = SignalDict()
    values.init(s)
    values.init(s0)
    values.init(s1)

    values[s] += 1
    assert np.array_equal(values[s0], value[s0slice].reshape(s0shape) + 1)
    assert np.array_equal(values[s1], value[s1slice].reshape(s1shape) + 1)

def test_signaldict_reset():
    """Tests SignalDict's reset function."""
    signaldict = SignalDict()
    two_d = Signal([[1.], [1.]])
    signaldict.init(two_d)

    two_d_view = two_d[0, :]
    signaldict.init(two_d_view)

    signaldict[two_d_view] = -0.5
    assert np.allclose(signaldict[two_d], np.array([[-0.5], [1]]))

    signaldict[two_d] = np.array([[-1], [-1]])
    assert np.allclose(signaldict[two_d], np.array([[-1], [-1]]))
    assert np.allclose(signaldict[two_d_view], np.array([-1]))

    signaldict.reset(two_d_view)
    assert np.allclose(signaldict[two_d_view], np.array([1]))
    assert np.allclose(signaldict[two_d], np.array([[1], [-1]]))

    signaldict.reset(two_d)
    assert np.allclose(signaldict[two_d], np.array([[1], [1]]))

    def __init__(self, network, dt=0.001, seed=None, model=None):
        """Initialize the simulator with a network and (optionally) a model.

        Most of the time, you will pass in a network and sometimes a dt::

            sim1 = nengo.Simulator(my_network)  # Uses default 0.001s dt
            sim2 = nengo.Simulator(my_network, dt=0.01)  # Uses 0.01s dt

        For more advanced use cases, you can initialize the model yourself,
        and also pass in a network that will be built into the same model
        that you pass in::

            sim = nengo.Simulator(my_network, model=my_model)

        If you want full control over the build process, then you can build
        your network into the model manually. If you do this, then you must
        explicitly pass in ``None`` for the network::

            sim = nengo.Simulator(None, model=my_model)

        Parameters
        ----------
        network : nengo.Network instance or None
            A network object to the built and then simulated.
            If a fully built ``model`` is passed in, then you can skip
            building the network by passing in network=None.
        dt : float, optional
            The length of a simulator timestep, in seconds.
        seed : int, optional
            A seed for all stochastic operators used in this simulator.
        model : nengo.builder.Model instance or None, optional
            A model object that contains build artifacts to be simulated.
            Usually the simulator will build this model for you; however,
            if you want to build the network manually, or to inject some
            build artifacts in the Model before building the network,
            then you can pass in a ``nengo.builder.Model`` instance.
        """
        if model is None:
            dt = float(dt)  # make sure it's a float (for division purposes)
            self.model = Model(dt=dt,
                               label="%s, dt=%f" % (network, dt),
                               decoder_cache=get_default_decoder_cache())
        else:
            self.model = model

        if network is not None:
            # Build the network into the model
            self.model.build(network)

        self.model.decoder_cache.shrink()

        # -- map from Signal.base -> ndarray
        self.signals = SignalDict(__time__=np.asarray(0.0, dtype=np.float64))
        for op in self.model.operators:
            op.init_signals(self.signals)

        # Order the steps (they are made in `Simulator.reset`)
        self.dg = operator_depencency_graph(self.model.operators)
        self._step_order = [op for op in toposort(self.dg)
                            if hasattr(op, 'make_step')]

        # Add built states to the probe dictionary
        self._probe_outputs = self.model.params

        # Provide a nicer interface to probe outputs
        self.data = ProbeDict(self._probe_outputs)

        seed = np.random.randint(npext.maxint) if seed is None else seed
        self.reset(seed=seed)

class Simulator(object):
    """Reference simulator for Nengo models."""

    def __init__(self, network, dt=0.001, seed=None, model=None):
        """Initialize the simulator with a network and (optionally) a model.

        Most of the time, you will pass in a network and sometimes a dt::

            sim1 = nengo.Simulator(my_network)  # Uses default 0.001s dt
            sim2 = nengo.Simulator(my_network, dt=0.01)  # Uses 0.01s dt

        For more advanced use cases, you can initialize the model yourself,
        and also pass in a network that will be built into the same model
        that you pass in::

            sim = nengo.Simulator(my_network, model=my_model)

        If you want full control over the build process, then you can build
        your network into the model manually. If you do this, then you must
        explicitly pass in ``None`` for the network::

            sim = nengo.Simulator(None, model=my_model)

        Parameters
        ----------
        network : nengo.Network instance or None
            A network object to the built and then simulated.
            If a fully built ``model`` is passed in, then you can skip
            building the network by passing in network=None.
        dt : float, optional
            The length of a simulator timestep, in seconds.
        seed : int, optional
            A seed for all stochastic operators used in this simulator.
        model : nengo.builder.Model instance or None, optional
            A model object that contains build artifacts to be simulated.
            Usually the simulator will build this model for you; however,
            if you want to build the network manually, or to inject some
            build artifacts in the Model before building the network,
            then you can pass in a ``nengo.builder.Model`` instance.
        """
        if model is None:
            dt = float(dt)  # make sure it's a float (for division purposes)
            self.model = Model(dt=dt,
                               label="%s, dt=%f" % (network, dt),
                               decoder_cache=get_default_decoder_cache())
        else:
            self.model = model

        if network is not None:
            # Build the network into the model
            self.model.build(network)

        self.model.decoder_cache.shrink()

        # -- map from Signal.base -> ndarray
        self.signals = SignalDict(__time__=np.asarray(0.0, dtype=np.float64))
        for op in self.model.operators:
            op.init_signals(self.signals)

        # Order the steps (they are made in `Simulator.reset`)
        self.dg = operator_depencency_graph(self.model.operators)
        self._step_order = [op for op in toposort(self.dg)
                            if hasattr(op, 'make_step')]

        # Add built states to the probe dictionary
        self._probe_outputs = self.model.params

        # Provide a nicer interface to probe outputs
        self.data = ProbeDict(self._probe_outputs)

        seed = np.random.randint(npext.maxint) if seed is None else seed
        self.reset(seed=seed)

    @property
    def dt(self):
        """The time step of the simulator"""
        return self.model.dt

    @dt.setter
    def dt(self, dummy):
        raise AttributeError("Cannot change simulator 'dt'. Please file "
                             "an issue at http://github.com/nengo/nengo"
                             "/issues and describe your use case.")

    @property
    def time(self):
        """The current time of the simulator"""
        return self.signals['__time__'].copy()

    def trange(self, dt=None):
        """Create a range of times matching probe data.

        Note that the range does not start at 0 as one might expect, but at
        the first timestep (i.e., dt).

        Parameters
        ----------
        dt : float (optional)
            The sampling period of the probe to create a range for. If empty,
            will use the default probe sampling period.
#.........这里部分代码省略.........

class Simulator(object):
    """Reference simulator for Nengo models.

    The simulator takes a `.Network` and builds internal data structures to
    run the model defined by that network. Run the simulator with the
    `~.Simulator.run` method, and access probed data through the
    ``data`` attribute.

    Building and running the simulation may allocate resources like files
    and sockets. To properly free these resources, call the `.Simulator.close`
    method. Alternatively, `.Simulator.close` will automatically be called
    if you use the ``with`` syntax::

        with nengo.Simulator(my_network) as sim:
            sim.run(0.1)
        print(sim.data[my_probe])

    Note that the ``data`` attribute is still accessible even when a simulator
    has been closed. Running the simulator, however, will raise an error.

    Parameters
    ----------
    network : Network or None
        A network object to be built and then simulated. If None,
        then a `.Model` with the build model must be provided instead.
    dt : float, optional (Default: 0.001)
        The length of a simulator timestep, in seconds.
    seed : int, optional (Default: None)
        A seed for all stochastic operators used in this simulator.
    model : Model, optional (Default: None)
        A `.Model` that contains build artifacts to be simulated.
        Usually the simulator will build this model for you; however, if you
        want to build the network manually, or you want to inject build
        artifacts in the model before building the network, then you can
        pass in a `.Model` instance.

    Attributes
    ----------
    closed : bool
        Whether the simulator has been closed.
        Once closed, it cannot be reopened.
    data : ProbeDict
        The `.ProbeDict` mapping from Nengo objects to the data associated
        with those objects. In particular, each `.Probe` maps to the data
        probed while running the simulation.
    dg : dict
        A dependency graph mapping from each `.Operator` to the operators
        that depend on that operator.
    model : Model
        The `.Model` containing the signals and operators necessary to
        simulate the network.
    signals : SignalDict
        The `.SignalDict` mapping from `.Signal` instances to NumPy arrays.

    """

    # 'unsupported' defines features unsupported by a simulator.
    # The format is a list of tuples of the form `(test, reason)` with `test`
    # being a string with wildcards (*, ?, [abc], [!abc]) matched against Nengo
    # test paths and names, and `reason` is a string describing why the feature
    # is not supported by the backend. For example:
    #     unsupported = [('test_pes*', 'PES rule not implemented')]
    # would skip all test whose names start with 'test_pes'.
    unsupported = []

    def __init__(self, network, dt=0.001, seed=None, model=None):
        self.closed = False

        if model is None:
            dt = float(dt)  # make sure it's a float (for division purposes)
            self.model = Model(dt=dt,
                               label="%s, dt=%f" % (network, dt),
                               decoder_cache=get_default_decoder_cache())
        else:
            self.model = model

        if network is not None:
            # Build the network into the model
            self.model.build(network)

        self.model.decoder_cache.shrink()

        # -- map from Signal.base -> ndarray
        self.signals = SignalDict()
        for op in self.model.operators:
            op.init_signals(self.signals)

        # Order the steps (they are made in `Simulator.reset`)
        self.dg = operator_depencency_graph(self.model.operators)
        self._step_order = [op for op in toposort(self.dg)
                            if hasattr(op, 'make_step')]

        # Add built states to the probe dictionary
        self._probe_outputs = self.model.params

        # Provide a nicer interface to probe outputs
        self.data = ProbeDict(self._probe_outputs)

        seed = np.random.randint(npext.maxint) if seed is None else seed
        self.reset(seed=seed)
#.........这里部分代码省略.........

class Simulator(object):
    """Reference simulator for Nengo models."""

    def __init__(self, network, dt=0.001, seed=None, model=None):
        """Initialize the simulator with a network and (optionally) a model.

        Most of the time, you will pass in a network and sometimes a dt::

            sim1 = nengo.Simulator(my_network)  # Uses default 0.001s dt
            sim2 = nengo.Simulator(my_network, dt=0.01)  # Uses 0.01s dt

        For more advanced use cases, you can initialize the model yourself,
        and also pass in a network that will be built into the same model
        that you pass in::

            sim = nengo.Simulator(my_network, model=my_model)

        If you want full control over the build process, then you can build
        your network into the model manually. If you do this, then you must
        explicitly pass in ``None`` for the network::

            sim = nengo.Simulator(None, model=my_model)

        Parameters
        ----------
        network : nengo.Network instance or None
            A network object to the built and then simulated.
            If a fully built ``model`` is passed in, then you can skip
            building the network by passing in network=None.
        dt : float
            The length of a simulator timestep, in seconds.
        seed : int
            A seed for all stochastic operators used in this simulator.
            Note that there are not stochastic operators implemented
            currently, so this parameters does nothing.
        model : nengo.builder.Model instance or None
            A model object that contains build artifacts to be simulated.
            Usually the simulator will build this model for you; however,
            if you want to build the network manually, or to inject some
            build artifacts in the Model before building the network,
            then you can pass in a ``nengo.builder.Model`` instance.
        """
        dt = float(dt)  # make sure it's a float (for division purposes)

        if model is None:
            self.model = Model(dt=dt,
                               label="%s, dt=%f" % (network, dt),
                               decoder_cache=get_default_decoder_cache())
        else:
            self.model = model

        if network is not None:
            # Build the network into the model
            self.model.build(network)

        self.model.decoder_cache.shrink()

        self.seed = np.random.randint(npext.maxint) if seed is None else seed
        self.rng = np.random.RandomState(self.seed)

        # -- map from Signal.base -> ndarray
        self.signals = SignalDict(__time__=np.asarray(0.0, dtype=np.float64))
        for op in self.model.operators:
            op.init_signals(self.signals)

        self.dg = operator_depencency_graph(self.model.operators)
        self._step_order = [node for node in toposort(self.dg)
                            if hasattr(node, 'make_step')]
        self._steps = [node.make_step(self.signals, dt, self.rng)
                       for node in self._step_order]

        # Add built states to the probe dictionary
        self._probe_outputs = self.model.params

        # Provide a nicer interface to probe outputs
        self.data = ProbeDict(self._probe_outputs)

        self.reset()

    @property
    def dt(self):
        """The time step of the simulator"""
        return self.model.dt

    @dt.setter
    def dt(self, dummy):
        raise AttributeError("Cannot change simulator 'dt'. Please file "
                             "an issue at http://github.com/ctn-waterloo/nengo"
                             "/issues and describe your use case.")

    @property
    def time(self):
        """The current time of the simulator"""
        return self.signals['__time__'].copy()

    def trange(self, dt=None):
        """Create a range of times matching probe data.

        Parameters
        ----------
#.........这里部分代码省略.........

class Simulator(object):
    """Reference simulator for Nengo models."""

    # 'unsupported' defines features unsupported by a simulator.
    # The format is a list of tuples of the form `(test, reason)` with `test`
    # being a string with wildcards (*, ?, [abc], [!abc]) matched against Nengo
    # test paths and names, and `reason` is a string describing why the feature
    # is not supported by the backend. For example:
    #     unsupported = [('test_pes*', 'PES rule not implemented')]
    # would skip all test whose names start with 'test_pes'.
    unsupported = []

    def __init__(self, network, dt=0.001, seed=None, model=None):
        """Initialize the simulator with a network and (optionally) a model.

        Most of the time, you will pass in a network and sometimes a dt::

            sim1 = nengo.Simulator(my_network)  # Uses default 0.001s dt
            sim2 = nengo.Simulator(my_network, dt=0.01)  # Uses 0.01s dt

        For more advanced use cases, you can initialize the model yourself,
        and also pass in a network that will be built into the same model
        that you pass in::

            sim = nengo.Simulator(my_network, model=my_model)

        If you want full control over the build process, then you can build
        your network into the model manually. If you do this, then you must
        explicitly pass in ``None`` for the network::

            sim = nengo.Simulator(None, model=my_model)

        Parameters
        ----------
        network : nengo.Network instance or None
            A network object to the built and then simulated.
            If a fully built ``model`` is passed in, then you can skip
            building the network by passing in network=None.
        dt : float, optional
            The length of a simulator timestep, in seconds.
        seed : int, optional
            A seed for all stochastic operators used in this simulator.
        model : nengo.builder.Model instance or None, optional
            A model object that contains build artifacts to be simulated.
            Usually the simulator will build this model for you; however,
            if you want to build the network manually, or to inject some
            build artifacts in the Model before building the network,
            then you can pass in a ``nengo.builder.Model`` instance.
        """
        self.closed = False

        if model is None:
            dt = float(dt)  # make sure it's a float (for division purposes)
            self.model = Model(dt=dt,
                               label="%s, dt=%f" % (network, dt),
                               decoder_cache=get_default_decoder_cache())
        else:
            self.model = model

        if network is not None:
            # Build the network into the model
            self.model.build(network)

        self.model.decoder_cache.shrink()

        # -- map from Signal.base -> ndarray
        self.signals = SignalDict()
        for op in self.model.operators:
            op.init_signals(self.signals)

        # Order the steps (they are made in `Simulator.reset`)
        self.dg = operator_depencency_graph(self.model.operators)
        self._step_order = [op for op in toposort(self.dg)
                            if hasattr(op, 'make_step')]

        # Add built states to the probe dictionary
        self._probe_outputs = self.model.params

        # Provide a nicer interface to probe outputs
        self.data = ProbeDict(self._probe_outputs)

        seed = np.random.randint(npext.maxint) if seed is None else seed
        self.reset(seed=seed)

    def __del__(self):
        """Raise a ResourceWarning if we are deallocated while open."""
        if not self.closed:
            warnings.warn(
                "Simulator with model=%s was deallocated while open. Please "
                "close simulators manually to ensure resources are properly "
                "freed." % self.model, ResourceWarning)

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        self.close()

    @property
    def dt(self):
#.........这里部分代码省略.........