Including channels in a pip_requirements.txt file

Python Help
1

In a pip_requirements.txt file, is there a way to specify the channel to use for some specific packages to avoid having to call pip twice as below:

pip install -r env_requirements.txt
pip install torch torchvision torchaudio --index-url https://download.pytorch.org/whl/cu118

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2

To my understanding, each line of the file is literally just a listing of command-line arguments for an invocation of Pip; so you should be able to just write e.g. torch torchvision torchaudio --index-url https://download.pytorch.org/whl/cu118 on a line of the file.

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3

Unfortunately, it doesn’t work as expected in most cases (every computer i tried). He’s right about having to call pip twice in this scenario.

4

--index-url is a global option, it must be on its own line and is valid for the whole file: Requirements File Format - pip documentation v24.0

5

Yes, it’s nice to mention it too, beacause it’s the reason why he has to call pip twice in this scenario.

6

My solution for you to use only one pip command line is as follows:

Keep your original requiments.txt file as it is.

Create another requirements.txt file but with a different name, such as ‘requirements2.txt’.

So, you can call pip once using ‘pip install -r requirements1.txt -r requirements2.txt’

edit: Don’t forget to index the url in a single line in requirements2.txt, before you call the packages.