Chainer

Chainer is an open source deep learning framework written purely in Python on top of Numpy and CuPy Python libraries.

The development is led by Japanese venture company Preferred Networks in partnership with IBM, Intel, Microsoft, and Nvidia.Chainer is notable for its early adoption of "define-by-run" scheme, as well as its performance on large scale systems.

The first version was released in June 2015 and has gained large popularity in Japan since then. Furthermore in 2017, it was listed by KDnuggets in top 10 open source machine learning Python projects.