Where do I get a CPU-only version of PyTorch?

Question

I'm trying to get a basic app running with Flask + PyTorch, and host it on Heroku. However, I run into the issue that the maximum slug size is 500mb on the free version, and PyTorch itself is ~500mb.

After some google searching, someone wrote about finding a cpu-only version of PyTorch, and using that, which is much smaller here.

However, I'm pretty lost as to how this is done, and the person didn't document this at all. Any advice is appreciated, thanks.

EDIT:

To be more specific about my problem, I tried installing torch by (as far as I understand), including a requirements.txt which listed torch as a dependency. Current I have: torch==0.4.1. However this doesn't work bc of size.

My question is, do you know what I could write in the requirements file to get the cpu-only version of torch that is smaller, or alternatively, if the requirements.txt doesn't work for this, what I would do instead, to get the cpu version.

Answer 1

Per the Pytorch website, you can install pytorch-cpu with

conda install pytorch-cpu torchvision-cpu -c pytorch 

You can see from the files on Anaconda cloud, that the size varies between 26 and 56MB depending on the OS where you want to install it.

You can get the wheel from http://download.pytorch.org/whl/cpu/. The wheel is 87MB.

You can setup the installation by putting the link to the wheel in the requirements.txt file. If you use Python 3.6 on Heroku:

http://download.pytorch.org/whl/cpu/torch-0.4.1-cp36-cp36m-linux_x86_64.whl 

otherwise, for Python 2.7:

http://download.pytorch.org/whl/cpu/torch-0.4.1-cp27-cp27mu-linux_x86_64.whl 

For example if your requirements are pytorch-cpu, numpy and scipy and you're using Python 3.6, the requirements.txt would look like:

http://download.pytorch.org/whl/cpu/torch-0.4.1-cp36-cp36m-linux_x86_64.whl numpy scipy 

Answer 2

As of PyTorch 1.3, PyTorch has changed its API. In order to install CPU version only, use

conda install pytorch torchvision cpuonly -c pytorch 

And, the corresponding wheel files can be downloaded from https://download.pytorch.org/whl/torch_stable.html and can be installed using pip or use the command similar to the following corresponding to your intended pytorch and torchvision versions

On Linux:

pip3 install torch==1.9.0+cpu torchvision==0.10.0+cpu -f https://download.pytorch.org/whl/torch_stable.html 

On Windows / Mac:

pip3 install torch torchvision 

Check the PyTorch's getting started guide.