when i used conda install torch :
 conda install pytorch torchvision torchaudio cudatoolkit=10.1
Collecting package metadata (current_repodata.json): done
Solving environment: failed with initial frozen solve. Retrying with flexible solve.
Collecting package metadata (repodata.json): done
Solving environment: failed with initial frozen solve. Retrying with flexible solve.

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

  - cudatoolkit=10.1
  - torchvision
  - pytorch
  - torchaudio

Current channels:

  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main/win-32
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main/noarch
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/r/win-32
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/r/noarch
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/msys2/win-32
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/msys2/noarch

To search for alternate channels that may provide the conda package you're
looking for, navigate to

    https://anaconda.org

and use the search bar at the top of the page.

when i used pip install pytorch :
 pip install torch==1.7.1+cu101 torchvision==0.8.2+cu101 torchaudio===0.7.2 -f https://download.pytorch.org/whl/torch_stable.html
Looking in links: https://download.pytorch.org/whl/torch_stable.html
ERROR: Could not find a version that satisfies the requirement torch==1.7.1+cu101
ERROR: No matching distribution found for torch==1.7.1+cu101