ImportError: cannot import name 'Correlation' from 'mmcv.ops'

[Z-XQ]

window10
cuda10.2
pytorch1.6
python3.7
mmcv1.1.5

my first try failed. is the version of mmcv too old?

error info:
ImportError: cannot import name 'Correlation' from 'mmcv.ops'

[MeowZheng]

Yes, it's too old. Please double-check prerequisites, and MMFlow needs MMCV 1.3.15+

[Z-XQ]

Thanks for your relpy! I just built MMCV from source, and the version is 1.3.17 (newest). But I get the error info as following.

error info:
Traceback (most recent call last):
File "D:/code/PycharmProjects/mmflow-master/verify_install.py", line 12, in
from mmflow.apis import inference_model, init_model
File "D:\code\PycharmProjects\mmflow-master\mmflow\apis_init_.py", line 2, in
from .inference import inference_model, init_model
File "D:\code\PycharmProjects\mmflow-master\mmflow\apis\inference.py", line 8, in
from mmcv.ops import Correlation
File "d:\code\pycharmprojects\mmcv-master\mmcv\ops_init_.py", line 2, in
from .assign_score_withk import assign_score_withk
File "d:\code\pycharmprojects\mmcv-master\mmcv\ops\assign_score_withk.py", line 6, in
'ext', ['assign_score_withk_forward', 'assign_score_withk_backward'])
File "d:\code\pycharmprojects\mmcv-master\mmcv\utils\ext_loader.py", line 13, in load_ext
ext = importlib.import_module('mmcv.' + name)
File "C:\Users\Administrator.conda\envs\mmflow\lib\importlib_init.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
ModuleNotFoundError: No module named 'mmcv._ext'

conda list:
cudatoolkit 10.2.89 h74a9793_1 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main
mmcv 1.3.17 dev_0
mmflow 0.1.0 dev_0
python 3.7.11 h6244533_0 defaults
pytorch 1.6.0 py3.7_cuda102_cudnn7_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/pytorch
torchvision 0.7.0 py37_cu102 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/pytorch
vc 14.2 h21ff451_1 defaults
vs2015_runtime 14.27.29016 h5e58377_2 defaults

[MeowZheng]

In this part, we have explained the cause of this problem.

In addition, please check out mmcv installation documents and make sure mmcv-full has been installed successfully.

[MeowZheng]

No further discussion

[Z-XQ]

In this part, we have explained the cause of this problem.

In addition, please check out mmcv installation documents and make sure mmcv-full has been installed successfully.

Thank you! I have solved this problem and wrote a blog to describe this.