The mmcv-full version problem. How can I install it properly?

[zhujilin1995]

Environment

1. It requires the mmcv-full version is mmcv-full>=1.3.15,<1.7.0, but when I install the mmcv-full==1.6.2 and run the code, it shows that _ImportError: DLL load failed while importing ext. I don't know what is wrong with it. Could you please help me? Thank you so much.
2. • How I installed PyTorch [conda]

Error traceback
File "E:\Ana\envs\optiFlow_1\lib\site-packages\mmcv\ops_init_.py", line 2, in
from .active_rotated_filter import active_rotated_filter
File "E:\Ana\envs\optiFlow_1\lib\site-packages\mmcv\ops\active_rotated_filter.py", line 10, in
ext_module = ext_loader.load_ext(
File "E:\Ana\envs\optiFlow_1\lib\site-packages\mmcv\utils\ext_loader.py", line 13, in load_ext
ext = importlib.import_module('mmcv.' + name)
File "E:\Ana\envs\optiFlow_1\lib\importlib_init_.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
ImportError: DLL load failed while importing _ext: