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Is there a way to specify the architecture/platform when creating a new conda environment? Alternatively, how does conda detect its current architecture/platform when its run?

What I'm aiming to do is this: I'm running on an Apple Silicon laptop. My pre-existing environments are running fine through Rosetta2, but I'd like to start experimenting with python running natively on Apple Silicon. miniforge provides a conda-forge repository with Apple Silicon builds, and I can tell conda to use the conda-forge channel when I create an environment. But I'm not seeing a way to specify that I'd like this to be an arm64 environment rather than an x86_64 environment, other than starting from miniforge's installer.

Thanks in advance.

Bob
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  • It should detect it from the OS. – James Dec 23 '20 at 11:16
  • I'm sure that's true, its detecting from the OS. But perhaps you could share precisely how its doing that, or where, or by what variable, or how that detection might be overridden? – Bob Dec 23 '20 at 17:50
  • You can try [setting subdir constraints](https://stackoverflow.com/a/58014896/570918) which is effectively how Conda segregates different platforms (win/osx/linux) and architectures (32/64). – merv Dec 23 '20 at 19:31
  • @merv Thanks! That looks like its on the right path to an answer. I think I'd have to combine it with the conda commands to specify a channel and not to use channel fallbacks. May work. If you want to take your comment and turn it into a complete answer, I'll try it and select it as correct. – Bob Dec 23 '20 at 22:59

1 Answers1

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CONDA_SUBDIR=osx-arm64 conda create -n native numpy -c conda-forge will get you a osx-arm64 native env.

To make it permanent, do,

conda activate numpy
conda config --env --set subdir osx-arm64
isuruf
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    Thanks! I got it to work with `CONDA_SUBDIR=osx-arm64 conda create -n py39_native python=3.9 -c conda-forge --override-channels` I'm pretty sure you need the last bit. If you want to add that to your answer I'll accept it as correct. – Bob Dec 24 '20 at 04:55
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    `--override-channels` is not strictly necessary. `-c conda-forge` is not needed if you have it already in your channels, but added it anyways. – isuruf Dec 24 '20 at 18:34
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    This should be run in the new environment after creation: `conda env config vars set CONDA_SUBDIR=osx-arm64` Otherwise future installs will revert to osx_64 – Bob Dec 24 '20 at 19:25
  • @isuruf the `--override-channels` can safeguard against situations where users have other subdirs set in their configuration settings. Without it, the default `channel_priority` setting of `"flexible"`, leaves users open to Conda solving for packages from outside the specified subdir. Alternatively, using `"strict"` priority for channels can also work. So yeah, not strictly necessary, but it is a good defensive suggestion. – merv Feb 16 '21 at 03:30
  • @Bob Thanks, this solved my problem. – Pedram Jan 15 '22 at 18:28