The story behind Yann¶
I am Ragav Venkatesan, the creator of Yann. I started building convolutional neural networks in early 2015. I began with theano and started following and implementing their tutorials. As I started reading new papers and coding new technologies, I slowly integrated them into what was soon developing into a toolbox. My lab mates at Visual Representaiton and Processing Group also started getting into CNN research and started using my toolbox so I formalized it and hosted it on GitHub. Originally it was a completely unstructured and completely demodularized toolbox and went with the name ‘samosa’. The original codebase still exists in older commits on the git. This toolbox still at its core is still the theano tutorials from which it was built.
After considerable effort being put in to make this toolbox modular, and testing it out and after using the toolbox on some of my own research. This toolbox, which began as a pet project is something that I am now proud to share with the rest of DL community with.
This toolbox is also used with the course CSE 591 at ASU in Spring of 2017. With more features being added into the toolbox, I figured I would clean it up, formalize it and write some good documentation so that interested people could use it after. Thus after being rechristened as Yann, this toolbox was born.
This is a personal toolbox that I wrote as a project for myself. I promise nothing. Although I try to make sure everything is perfectly working. I encourage anyone to use it, contribute to it and write on top of it with that caveat. I still have a lot of code to be written - unittests, optimizers, pre-trained models, dataset ports and for all of these I would really appreciate contributors and help.
I am working on tutorials and quickstart guides for this toolbox. As such, I try to go in detail in these tutorials, but I am assuming a pre-requisite training and knowledge on CNNs and Neural Neworks. If you are here looking for a tutorial for those and are disappointed with the material here, please read Prof. Yoshua Bengio’s book on Deep Learning, or read the examples from theano tutorials. Theano tutorials also will help understand theano which is the backend I used for this toolbox. As the course begins, I will add more tutorials with notes that will make this more useful and interactive.
What is in the toolbox ?¶
This toolbox started with the beautiful theano tutorials. The code that is here in yann has the following popular features that all deep net toolboxes seem to have. Among many others there are:
CNNs with easy architecture management: Because layers can take origins as inputs, pretty much any architecture that can be drawn on a blackboard can be constructed using this toolbox.
Dataset handling capabilities: Features to setup data as simple matlab files that can be loaded in python and run in batches for training. Alternatively, there is also a wrapper to skdata’s dataset interface and future plans for adding the Fuel interface also. As of now, directt ports through
skdatato cifar10, mnist, extended mnists for Hugo Larochelle , caltech101, caltech256. More to be added soon.
Data visualization capabilities: Visualize the activities of select images (or random) from the train set on each layer after select number of epochs of training. Also view filters after select number of epochs. I find this very effective for my understanding.
Techniques from recent publications: This is where things change a lot and for someone who is getting into deep learning fresh without much theoretical machine learning it would be really helpful. With only a few flags and parameters, one could switch entire optimization methods, including gradient descent, adaGrad, rmsProp add momentums like Polyak Momentum, Nesterov’s accelerated gradients etc. One switch converts the whole networks into a max-margin formulation from a softmax formulation. All of these options are plug and play or more like add and cook. Most new methods that are recently published and are added including but not limited to:
- Polyak Momentum
- Nesterov’s Accelerated Gradients 
- rmsProp 
- *Adam 
- Maxout and Mixed out Networks 
- *FitNets and MentorNets[9,15]
- VGG-19 
- *Inception Module 
- Batch Normalization 
- ReLU / ELU and other activations supported through theano [13,14]
- Generative Adversarial Networks 
Those marked * are not fully tested yet.
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|||Polyak, Boris Teodorovich. “Some methods of speeding up the convergence of iteration methods.” USSR Computational Mathematics and Mathematical Physics 4.5 (1964): 1-17. Implementation was adapted from Sutskever, Ilya, et al. “On the importance of initialization and momentum in deep learning.” Proceedings of the 30th international conference on machine learning (ICML-13). 2013.|
|||Nesterov, Yurii. “A method of solving a convex programming problem with convergence rate O (1/k2).” Soviet Mathematics Doklady. Vol. 27. No. 2. 1983. Adapted from Sebastien Bubeck’s blog.|
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|||Ioffe, Sergey, and Christian Szegedy. “Batch normalization: Accelerating deep network training by reducing internal covariate shift.” arXiv preprint arXiv:1502.03167 (2015).|
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|||Clevert, Djork-Arné, Thomas Unterthiner, and Sepp Hochreiter. “Fast and accurate deep network learning by exponential linear units (elus).” arXiv preprint arXiv:1511.07289 (2015).|
|||Venkatesan, Ragav, and Baoxin Li. “Diving deeper into mentee networks.” arXiv preprint arXiv:1604.08220 (2016).|
|||Goodfellow, Ian, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. “Generative adversarial nets.” In Advances in Neural Information Processing Systems, pp. 2672-2680. 2014.|