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Debugging machine learning models is difficult at the best of times.

Mathy integrates with great tools to help make debugging easier.

Visual Studio Code

Mathy works with Visual Studio code to allow interactive debugging of your models.

When combined with Tensorflow 2.0's eager-mode execution, you can not only debug, but also develop your models from inside the debugger.


First download Visual Studio Code if you don't have it.

It's a free code editor with great features.

Run Configurations

In order to launch Mathy in the debugger, we add a new "Run Configuration"

The JSON blob we want to add looks like this:

  "name": "Train Mathy Agent",
  "type": "python",
  "request": "launch",
  "justMyCode": false,
  "module": "mathy",
  "args": ["train", "poly", "training/dev_agent", "--workers=1"]

By opening up launch.json we can insert the new configuration.

How to edit launch.json

Click the "Debug and Run" tab on the left side of the application. It looks like a bug icon.

Near the top of the app it will say "Debug and Run" with a green arrow icon, and a cog icon next to it.

Click on the cog icon to open launch.json

After adding the run configuration, we can set a breakpoint and launch the training process.

Set a breakpoint and launch the debugger

In the image above there are three points to pay attention to:

  1. To left of any code line you can click and a dot will appear indicating that a breakpoint is set.
  2. The Debug and Run side bar element in the VSCode app shows the Run Bar
  3. The Run Bar element is a drop-down menu that now contains your launch item

Clicking on the green arrow next to the new launch configuration will start the training process.

By adding a breakpoint, when Mathy gets to the line of code we specify, it will stop executing and bring the code editor into view.

While the program is stopped in the debugger we can experiment and debug code to figure out why something is going wrong.


Mathy agents export a rich set of information to Tensorboard whenever you do agent training.

Tensorboard is a tool developed by Google to analyze Tensorflow models.


pip install tensorboard


Start a training loop:

mathy train a3c poly ./training/my_model

While the loop is running, execute tensorboard in a separate terminal:

tensorboard --logdir=./training/my_model

It will output a link to the webpage. This is usually http://localhost:6006


The mathy model graph is available in the "Graphs" tab of the Tensorboard UI:

View model graphs in Tensorboard

Here you can view the connections between layers in the model, and better understand the architecture your model implements.


The scalars tab tracks vital metrics like the average episode reward, and all the losses that are used to compute gradients.

View model scalars in Tensorboard


The histograms tab shows the change over time trainable weights. It can be useful for identifying if your model is not learning because of a bad architecture.

View model histograms in Tensorboard

Problem Texts

The "text" tab receives reports of which problems are solved properly and which are not.

It outputs the input/output texts as well as the problem complexity.

View model problem texts in Tensorboard



Which you can install if it's not already present:

pip install snakeviz


If you use the --profile flag when training from the CLI, Mathy will save performance profiles for each worker instance on exit.

mathy train a3c poly ./training/my_model --profile

The profiler output files can be loaded in Snakeviz

Then view the output from the previous run:

snakeviz ./training/my_model/worker_0.profile

Running the above command will launch a webpage on your local system.

View agent performance profile in Skakeviz

Last update: July 24, 2020