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Web-based GUI for building and visualizing Nengo models.

Project description


HTML5 interactive visualizer for Nengo. This lets you see the structure of a Nengo model, plot spiking activity and decoded representations, and adjust the inputs while the model is running.


  • Python (tested with Python 2.7 and Python 3.4)
  • Nengo (which also requires NumPy)


The simplest way to install is with the standard Python installation system:

pip install nengo_gui

If you would like access the the development version of nengo_gui, you can download it from guthub:

git clone
cd nengo_gui
python develop --user

Running nengo_gui

There are two ways to run nengo_gui. First, you can use it from the command line by running the installed script:


If you specify a file to load, nengo_gui will do so:


Alternatively, you can start nengo_gui manually from within your code. To do so, add this to the bottom of your file that defines your Nengo model.

import nengo_gui

Basic usage

The graph of the Nengo network should appear. Rectangles are nengo.Nodes, ellipses are nengo.Ensembles, and rounded rectangles are nengo.Networks.

Items can be dragged to move them and resized by dragging their edge or via the scroll wheel.

To start (or continue) the simulation, click the play button in the lower right. A spinning gear icon indicates the model is in the process of being built (or re-built after new graphs are added).

Clicking on an item will show a menu of options, depending on what you have clicked on. Here are some of the standard options for network items:

  • value: show a graph of the decoded output value over time
  • xy-value: show a state-space plot of two decoded values against each other
  • spikes: show the spiking activity of the nengo.Ensemble
  • slider: show sliders that let you adjust the value in a nengo.Node
  • expand/collapse: reveal or hide the insides of a nengo.Network

Once you have graphs, you can also click on them to adjust their options. For example:

  • set range: adjust the limits of the graph
  • show label/hide label: whether to show the title at the top of the graph
  • remove: get rid of the graph

The graphs record their data from previous time steps. You can show this previous data by dragging the transparent area in the time axis at the bottom (beside the play button).

Release History

0.1.5 (November 3, 2015)

  • Added a set of tutorials to the built-in examples.
  • Added cross-hairs when hovering over plots.
  • Added several new types of plots, including a firing pattern plot, a similarity plot for SPA networks, and a plot for Compare networks.
  • Added the ability to implement custom HTML plots. See the built-in example basics/
  • Extended SPA override capabilities to all SPA networks.
  • nengo_gui.Viz has been renamed to nengo_gui.GUI.
  • Major refactoring of back-end code.
  • Many bug fixes and look-and-feel improvements.

0.1.4 (June 16, 2015)

  • Spike rasters are now much faster.
  • Added a reset button that restarts a simulation.
  • Code editor now has a border, making it easier to resize.
  • Can now search in the code editor (with Ctrl+f).
  • When an error occurs in a model, a console will display with error details. Printed values also show up in this console, for easier debugging.
  • Can now import from other files in the same directory as a Nengo model.
  • Readonly files are handled safely, instead of crashing.
  • Several minor aestheic improvements and bug fixes.

0.1.3 (June 10, 2015)

  • Fixed another Python 3 compatibility issue with autolayouts.
  • Fixed a bug that could cause a crash when reloading config files.

0.1.2 (June 9, 2015)

  • Fixed a Python 3 compatibility issue with semantic pointer graphs.

0.1.1 (June 8, 2015)

  • A large number of stability and user experience fixes. The first release was a bit buggy, but this should be pretty stable.
  • Includes many more examples out of the box.

0.1.0 (June 5, 2015)

Initial release of Nengo GUI! Thanks to all of the contributors for making this possible!

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