Win11+Visual Studio 2022,install successfully.

Start with the Windows installation command and the reported CUDA detection error, then inspect apex/amp/_amp_state.py and apex/amp/_initialize.py for the torch._six imports. Check the fused_layer_norm_cuda import path and compare the documented environment setup with the failing configuration. Done should be a reproducible installation and successful import on the stated versions.

win11
Python 3.11.8
CUDA Ver: 11.8
torch Ver: 2.3.0+cu118
torchvision Ver: 0.18.0+cu118
torchaudio Ver: 2.3.0+cu118
cuDNN Ver: 8700
Visual Studio 2022 安装 使用 C++ 桌面开发

参考：https://github.com/NVIDIA/apex/issues/835#issuecomment-646112354

cd D:+AI\ComfyUI\ComfyUI_windows_portable\python_embeded
git clone https://github.com/NVIDIA/apex
cd apex
git checkout 2ec84eb
..\python -m pip install -v --no-cache-dir --global-option="--cpp_ext" --global-option="--cuda_ext" .
Successfully installed apex-0.1
Error:
raw_output = subprocess.check_output([cuda_dir + "/bin/nvcc", "-V"], universal_newlines=True)
FileNotFoundError: [WinError 2] 系统找不到指定的文件。
Solved:
这里需要注意的是，在安装pytorch时会自动装上CUDA和cuDNN包并且会劫持调用，我们仍要在系统中安装上相同版本的CUDA和cuDNN。
set | findstr CUDA
注意CUDA_DIR要大写：set当前窗生效，setx写入环境变量，重新开窗仍有效
set CUDA_DIR="C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v11.8"
setx /m CUDA_DIR "C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v11.8"
验证：
..\python.exe -m pip list | findstr apex
..\python -c "from apex import amp"
Error:
No module named 'torch._six'
Solved:
cmd运行：（只能在同盘符中运行）（windows下如果安装了git是有sed这个命令的，把 C:\Program Files\Git\usr\bin 添加到系统变量Path中）
sed -i 's/from torch._six import container_abcs/import collections.abc as container_abcs/' "D:+AI\ComfyUI\ComfyUI_windows_portable\python_embeded\Lib\site-packages\apex\amp_amp_state.py"
sed -i 's/from torch._six import string_classes/string_classes = str/' "D:+AI\ComfyUI\ComfyUI_windows_portable\python_embeded\Lib\site-packages\apex\amp_initialize.py"
再次验证：
..\python -c "import apex;import importlib;global fused_layer_norm_cuda;fused_layer_norm_cuda = importlib.import_module('fused_layer_norm_cuda')"
这是从comfyUI中的apex提炼出来的测试代码，没有错误提示则是成功。
Error:No module named 'fused_layer_norm_cuda'
Solved: 原因是安装apex时没有安装cuda版本，--cuda_ext 安装时必须带上。
经测试 comfyUI 运行正常。