问题：Warning: Torch did not find available GPUs on this system.
If your intention is to cross-compile, this is not an error.
By default, Apex will cross-compile for Pascal (compute capabilities 6.0, 6.1, 6.2),
Volta (compute capability 7.0), Turing (compute capability 7.5),
and, if the CUDA version is >= 11.0, Ampere (compute capability 8.0).
If you wish to cross-compile for a single specific architecture,
export TORCH_CUDA_ARCH_LIST="compute capability" before running setup.py.
我的步骤：
1、github上下载完apex包并压缩后开始安装（地址：https://github.com/NVIDIA/apex）复制解压缩后的文件存放地址D:Conda3apex-master，如：
2、进入anaconda powershell，输入命令conda activate pytorch-cpu进入自己的虚拟环境，输入命令cd D:Conda3apex-master进入下载的aped包所在目录，如图：
输入命令：python setup.py install 安装apex，这时出现以下提示：
Warning: Torch did not find available GPUs on this system.
If your intention is to cross-compile, this is not an error.
By default, Apex will cross-compile for Pascal (compute capabilities 6.0, 6.1, 6.2),
Volta (compute capability 7.0), Turing (compute capability 7.5),
and, if the CUDA version is >= 11.0, Ampere (compute capability 8.0).
If you wish to cross-compile for a single specific architecture,
export TORCH_CUDA_ARCH_LIST="compute capability" before running setup.py.
原因：我是windows系统，没有NVDIA显卡，没有安装GPU版本的pytorch，我的是cpu版pytorch
解决：运行export TORCH_CUDA_ARCH_LIST="compute capability"，如果出现下面的错误：export : 无法将“export”项识别为 cmdlet、函数、脚本文件或可运行程序的名称。请检查名称的拼写，如果包括路径，请确保路径
正确，然后再试一次。
所在位置 行:1 字符: 1
+ export TORCH_CUDA_ARCH_LIST="compute capability"
+ ~~~~~~
+ CategoryInfo : ObjectNotFound: (export:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException
使用命令：$env:TORCH_CUDA_ARCH_LIST="compute capability"
再次输入：python setup.py install
应该没有什么问题了，输入命令：pip list| findstr apex查看是否有apex
返回pycharm，查看apex应该没有再爆红了，
至此！
