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Temporary home for fastai v2 while it's being developed
Jupyter Notebook Python
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Welcome to fastai v2

NB: This is still in early development. Use v1 unless you want to contribute to the next version of fastai


You can get all the necessary dependencies by simply installing fastai v1: conda install -c fastai -c pytorch fastai. Or alternatively you can automatically install the dependencies into a new environment:

git clone
cd fastai2
conda env create -f environment.yml
source activate fastai2

Then, you can install fastai v2 with pip: pip install fastai2.

Or you can use an editable install (which is probably the best approach at the moment, since fastai v2 is under heavy development):

git clone
cd fastai2
pip install -e .[dev]

You should also use an editable install of fastcore to go with it.

To use fastai2.medical.imaging you'll also need to:

conda install pyarrow
pip install pydicom kornia opencv-python scikit-image


To run the tests in parallel, launch:



make test


After you clone this repository, please run nbdev_install_git_hooks in your terminal. This sets up git hooks, which clean up the notebooks to remove the extraneous stuff stored in the notebooks (e.g. which cells you ran) which causes unnecessary merge conflicts.

Before submitting a PR, check that the local library and notebooks match. The script nbdev_diff_nbs can let you know if there is a difference between the local library and the notebooks.

  • If you made a change to the notebooks in one of the exported cells, you can export it to the library with nbdev_build_lib or make fastai2.
  • If you made a change to the library, you can export it back to the notebooks with nbdev_update_lib.
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