There was a recent Reddit AMA with Yann LeCun's [1] where he comments on Torch7[slightly edited]: Torch is a numerical/scientific computing extension of LuaJIT

There was a recent Reddit AMA with Yann LeCun's [1] where he comments on Torch7[slightly edited]: Torch is a numerical/scientific computing extension of LuaJIT with an ML/neural net library on top. Torch7 is what is being used for deep learning R&D at NYU, at Facebook AI Research, at Deep Mind, and at Google Brain. (At Facebook) We are using Torch7 for many projects (as does Deep Mind and several groups at Google) and will be contributing to the public version. We are using Torch for most of our research projects (and some of our development projects) at Facebook. Deep Mind is also using Torch in a big way (largely because my former student and Torch-co-maintainer Koray Kavukcuoglu sold them on it). Since the Deep Mind acquisition, folks in the Google Brain group in Mountain View have also started to use it. Facebook, NYU, and Google/Deep Mind all have custom CUDA back-ends for fast/parallel convolutional network training. Some of this code is not (yet) part of the public distribution. The huge advantage of LuaJIT over Python is that it way, way faster, leaner, simpler, and that interfacing C/C++/CUDA code to it is incredibly easy and fast. Torch is maintained by Ronan Collobert (IDIAP), Koray Kavukcuoglu (Deep Mind. former s=PhD student of mine) and Clément Farabet (running his own startup. Also a former PhD student of mine). We have used Torch as the main research platform in my NYU lab for quite a while. You could say that Torch is the direct heir of Lush, though the maintainers are different. Lush was mostly maintained by Leon Bottou and me. Ralf Juengling took over the development of Lush2 a few years ago. [1] http://fastml.com/yann-lecuns-answers-from-the-reddit-ama/ http://fastml.com/yann-lecuns-answers-from-the-reddit-ama/