Nengo display/model freezing or not updating

General Discussion
1

For an assignment I have to use nengo in order to get familiar with the NEF. As I am not so familiar with computer science or working in a terminal in general, I just followed the steps that were given to me.

First I downloaded Anaconda in which I could open nengo from the Anaconda prompt. This opens a browser for me in which I see a display with a model, an editor and a block for error messages.

The problem is when I copy or retype the steps we are ought to take, either the display doesn’t update or it freezes. Since the error messages that update as I copy part of these steps does update until a point, differing each time, I assume that it freezes. I am still able to type in the editor, but nothing happens in the display or error message block.

The code I have to copy in is the following:

import numpy as np
import nengo

model = nengo.Network(label=’Many Neurons’)
with model:
    # Our ensemble consists of 100 leaky integrate-and-fire neurons,
    # representing a one-dimensional signal
    A = nengo.Ensemble(100, dimensions=1)

with model:
    sin = nengo.Node(lambda t: np.sin(8 * t)) # Input is a sine

with model:
    # Connect the input to the population
    nengo.Connection(sin, A, synapse=0.01) # 10ms filter

with model:
    sin_probe = nengo.Probe(sin)
    A_probe = nengo.Probe(A, synapse=0.01) # 10ms filter
    A_spikes = nengo.Probe(A.neurons) # Collect the spikes

Does anyone know how to fix this or has similar problems?

2

The error is being cause by this line:
model = nengo.Network(label=’Many Neurons’)
and can be fixed by replacing it with:
model = nengo.Network(label='Many Neurons')

Basically, you’re using a weird unicode character to mark the Python string instead of a single-quote and this is breaking our parser. This probably happened when you copied the code from somewhere.

Ideally, our parser should be throwing an error in response to this, but for some reason it isn’t. I’ll make a bug and the Nengo devs will investigate this further. Thanks for bringing this to our attention.