Chainer is another neural network API that was developed by Seiya Tokui, who is currently a PhD student at the University of Tokyo in Japan. While it is less mainstream than Tensorflow, it is very well-respected due to its incredible speed and efficiency. Moreover, readers may find Chainer of particular interest, since this was originally developed using PyCUDA. (This was later switched to CuPy, which is a PyCUDA branch that was developed to provide an interface that is more similar to NumPy.)
Information on Chainer is available here: https://chainer.org/.
