What is PyTorch and how does it work?

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PyTorch is a Python-based scientific computing package that uses the power of graphics processing units. It is also one of the preferred deep learning research platforms built to provide maximum flexibility and speed. It is known for providing two of the most high-level features; namely, tensor computations with strong GPU acceleration support and building deep neural networks on a tape-based autograd systems.

There are many existing Python libraries which have the potential to change how deep learning and artificial intelligence are performed, and this is one such library. One of the key reasons behind PyTorch’s success is it is completely Pythonic and one can build neural network models effortlessly. It is still a young player when compared to its other competitors, however, it is gaining momentum fast.

A brief history of PyTorch

Since its release in January 2016, many researchers have continued to increasingly adopt PyTorch. It has quickly become a go-to library because of its ease in building extremely complex neural networks. It is giving a tough competition to TensorFlow especially when used for research work. However, there is still some time before it is adopted by the masses due to its still “new” and “under construction” tags.

PyTorch creators envisioned this library to be highly imperative which can allow them to run all the numerical computations quickly. This is an ideal methodology which fits perfectly with the Python programming style. It has allowed deep learning scientists, machine learning developers, and neural network debuggers to run and test part of the code in real time. Thus they don’t have to wait for the entire code to be executed to check whether it works or not.

You can always use your favorite Python packages such as NumPy, SciPy, and Cython to extend PyTorch functionalities and services when required. Now you might ask, why PyTorch? What’ so special in using it to build deep learning models?

The answer is quite simple, PyTorch is a dynamic library (very flexible and you can use as per your requirements and changes) which is currently adopted by many of the researchers, students, and artificial intelligence developers. In the recent Kaggle competition, PyTorch library was used by nearly all of the top 10 finishers.

Some of the key highlights of PyTorch includes:

  • Simple Interface: It offers easy to use API, thus it is very simple to operate and run like Python.
  • Pythonic in nature: This library, being Pythonic, smoothly integrates with the Python data science stack. Thus it can leverage all the services and functionalities offered by the Python environment.
  • Computational graphs: In addition to this, PyTorch provides an excellent platform which offers dynamic computational graphs, thus you can change them during runtime. This is highly useful when you have no idea how much memory will be required for creating a neural network model.

PyTorch Community

PyTorch community is growing in numbers on a daily basis. In the just short year and a half, it has shown some great amount of developments that have led to its citations in many research papers and groups. More and more people are bringing PyTorch within their artificial intelligence research labs to provide quality driven deep learning models.

The interesting fact is, PyTorch is still in early-release beta, but the way everyone is adopting this deep learning framework at a brisk pace shows its real potential and power in the community. Even though it is in the beta release, there are 741 contributors on the official GitHub repository working on enhancing and providing improvements to the existing PyTorch functionalities.

PyTorch doesn’t limit to specific applications because of its flexibility and modular design. It has seen heavy use by leading tech giants such as Facebook, Twitter, NVIDIA, Uber and more in multiple research domains such as NLP, machine translation, image recognition, neural networks, and other key areas.

Why use PyTorch in research?

Anyone who is working in the field of deep learning and artificial intelligence has likely worked with TensorFlow before, Google’s most popular open source library. However, the latest deep learning framework – PyTorch solves major problems in terms of research work. Arguably PyTorch is TensorFlow’s biggest competitor to date, and it is currently a much favored deep learning and artificial intelligence library in the research community.

Dynamic Computational graphs

It avoids static graphs that are used in frameworks such as TensorFlow, thus allowing the developers and researchers to change how the network behaves on the fly. The early adopters are preferring PyTorch because it is more intuitive to learn when compared to TensorFlow.

Different back-end support

PyTorch uses different backends for CPU, GPU and for various functional features rather than using a single back-end. It uses tensor backend TH for CPU and THC for GPU. While neural network backends such as THNN and THCUNN for CPU and GPU respectively. Using separate backends makes it very easy to deploy PyTorch on constrained systems.

Imperative style

PyTorch library is specially designed to be intuitive and easy to use. When you execute a line of code, it gets executed thus allowing you to perform real-time tracking of how your neural network models are built. Because of its excellent imperative architecture and fast and lean approach it has increased overall PyTorch adoption in the community.

Highly extensible

PyTorch is deeply integrated with the C++ code, and it shares some C++ backend with the deep learning framework, Torch. Thus allowing users to program in C/ C++ by using an extension API based on cFFI for Python and compiled for CPU for GPU operation. This feature has extended the PyTorch usage for new and experimental use cases thus making them a preferable choice for research use.


PyTorch is a native Python package by design. Its functionalities are built as Python classes, hence all its code can seamlessly integrate with Python packages and modules. Similar to NumPy, this Python-based library enables GPU-accelerated tensor computations plus provides rich options of APIs for neural network applications. PyTorch provides a complete end-to-end research framework which comes with the most common building blocks for carrying out everyday deep learning research. It allows chaining of high-level neural network modules because it supports Keras-like API in its torch.nn package.

PyTorch 1.0: The path from research to production

We have been discussing all the strengths PyTorch offers, and how these make it a go-to library for research work. However, one of the biggest downsides is, it has been its poor production support. But this is expected to change soon.

PyTorch 1.0 is expected to be a major release which will overcome the challenges developers face in production. This new iteration of the framework will merge Python-based PyTorch with Caffe2 allowing machine learning developers and deep learning researchers to move from research to production in a hassle-free way without the need to deal with any migration challenges. The new version 1.0 will unify research and production capabilities in one framework thus providing the required flexibility and performance optimization for research and production.

This new version promises to handle tasks one has to deal with while running the deep learning models efficiently on a massive scale. Along with the production support, PyTorch 1.0 will have more usability and optimization improvements. With PyTorch 1.0, your existing code will continue to work as-is, there won’t be any changes to the existing API. If you want to stay updated with all the progress to PyTorch library, you can visit the Pull Requests page.

The beta release of this long-awaited version is expected later this year. Major vendors like Microsoft and Amazon are expected to provide complete support to the framework across their cloud products.

Summing up, PyTorch is a compelling player in the field of deep learning and artificial intelligence libraries, exploiting its unique niche of being a research-first library. It overcomes all the challenges and provides the necessary performance to get the job done. If you’re a mathematician, researcher, student who is inclined to learn how deep learning is performed, PyTorch is an excellent choice as your first deep learning framework to learn.

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Sunith Shetty
Data Science fanatic. Cricket fan. Series Binge watcher. You can find me hooked to my PC updating myself constantly if I am not cracking lame jokes with my team.

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