Chainer is a powerful, flexible and intuitive deep learning framework.
* Chainer supports CUDA computation. It only requires a few lines of code to
  leverage a GPU. It also runs on multiple GPUs with little effort.
* Chainer supports various network architectures including feed-forward nets,
  convnets, recurrent nets and recursive nets. It also supports per-batch
  architectures.
* Forward computation can include any control flow statements of Python without
  lacking the ability of backpropagation. It makes code intuitive and easy to
  debug.

WWW: https://chainer.org/