Pytorch with cuda11.1 could't be downloaded in CI.

[mszhanyi]

🐛 Describe the bug

@seemethere ,
the PR #4082 removed the -c conda-forge.

After the change, I found that torch with cu11.1 couldn't be downloaded via
conda install -y -c "pytorch-${UPLOAD_CHANNEL}" "pytorch-${UPLOAD_CHANNEL}"::pytorch "${cudatoolkit}" pytest.

Is it expected?

Versions

after #4082

[prabhat00155]

Are you trying to install pytorch on cuda 11.1? You can try: conda install pytorch cudatoolkit=11.1 -c pytorch-nightly -c nvidia

[mszhanyi]

The link is
https://app.circleci.com/pipelines/github/pytorch/vision/10705/workflows/25d6740c-6c8a-42fd-8cbf-7a54222ebb38/jobs/816118

Installing PyTorch with cudatoolkit=11.1
Collecting package metadata (current_repodata.json): ...working... done
Solving environment: ...working... failed with initial frozen solve. Retrying with flexible solve.
Collecting package metadata (repodata.json): ...working... done
Solving environment: ...working... failed with initial frozen solve. Retrying with flexible solve.

PackagesNotFoundError: The following packages are not available from current channels:

  - cudatoolkit=11.1

Current channels:

  - https://conda.anaconda.org/pytorch-nightly/win-64
  - https://conda.anaconda.org/pytorch-nightly/noarch
  - https://repo.anaconda.com/pkgs/main/win-64
  - https://repo.anaconda.com/pkgs/main/noarch
  - https://repo.anaconda.com/pkgs/r/win-64
  - https://repo.anaconda.com/pkgs/r/noarch
  - https://repo.anaconda.com/pkgs/msys2/win-64
  - https://repo.anaconda.com/pkgs/msys2/noarch

And it could be solved by add '-c conda-forge'

What I'm confused about is why there's a PR to remove '-c conda-forge'

[prabhat00155]

I see. Looks like you need conda-forge on windows.

[prabhat00155]

Closing this issue, PR merged: #4475.