AttributeError: module 'torch.distributed' has no attribute '_all_gather_base'

[xc012]

Problem: The error “apex is not installed” during training, but it has been tried to install in various ways, including direct "pip install apex" and download source code and compilation.

Command: python tools/train.py configs/swin/mask_rcnn_swin_tiny_patch4_window7_mstrain_480-800_adamw_3x_coco.py

Error：
apex is not installed
Traceback (most recent call last):
File "tools/train.py", line 15, in
from mmdet.apis import set_random_seed, train_detector
File "/root/Swin-Transformer-Object-Detection-master/Swin-Transformer-Object-Detection/mmdet/apis/init.py", line 1, in
from .inference import (async_inference_detector, inference_detector,
File "/root/Swin-Transformer-Object-Detection-master/Swin-Transformer-Object-Detection/mmdet/apis/inference.py", line 11, in
from mmdet.datasets import replace_ImageToTensor
File "/root/Swin-Transformer-Object-Detection-master/Swin-Transformer-Object-Detection/mmdet/datasets/init.py", line 10, in
from .utils import (NumClassCheckHook, get_loading_pipeline,
File "/root/Swin-Transformer-Object-Detection-master/Swin-Transformer-Object-Detection/mmdet/datasets/utils.py", line 9, in
from mmdet.models.dense_heads import GARPNHead, RPNHead
File "/root/Swin-Transformer-Object-Detection-master/Swin-Transformer-Object-Detection/mmdet/models/init.py", line 1, in
from .backbones import * # noqa: F401,F403
File "/root/Swin-Transformer-Object-Detection-master/Swin-Transformer-Object-Detection/mmdet/models/backbones/init.py", line 13, in
from .swin_transformer import SwinTransformer
File "/root/Swin-Transformer-Object-Detection-master/Swin-Transformer-Object-Detection/mmdet/models/backbones/swin_transformer.py", line 13, in
from timm.models.layers import DropPath, to_2tuple, trunc_normal_
File "/root/.local/lib/python3.7/site-packages/timm/init.py", line 2, in
from .models import create_model, list_models, is_model, list_modules, model_entrypoint,
File "/root/.local/lib/python3.7/site-packages/timm/models/init.py", line 1, in
from .beit import *
File "/root/.local/lib/python3.7/site-packages/timm/models/beit.py", line 49, in
from timm.data import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
File "/root/.local/lib/python3.7/site-packages/timm/data/init.py", line 5, in
from .dataset import ImageDataset, IterableImageDataset, AugMixDataset
File "/root/.local/lib/python3.7/site-packages/timm/data/dataset.py", line 12, in
from .parsers import create_parser
File "/root/.local/lib/python3.7/site-packages/timm/data/parsers/init.py", line 1, in
from .parser_factory import create_parser
File "/root/.local/lib/python3.7/site-packages/timm/data/parsers/parser_factory.py", line 3, in
from .parser_image_folder import ParserImageFolder
File "/root/.local/lib/python3.7/site-packages/timm/data/parsers/parser_image_folder.py", line 11, in
from timm.utils.misc import natural_key
File "/root/.local/lib/python3.7/site-packages/timm/utils/init.py", line 4, in
from .cuda import ApexScaler, NativeScaler
File "/root/.local/lib/python3.7/site-packages/timm/utils/cuda.py", line 8, in
from apex import amp
File "", line 983, in _find_and_load
File "", line 967, in _find_and_load_unlocked
File "", line 668, in _load_unlocked
File "", line 638, in _load_backward_compatible
File "/opt/conda/lib/python3.7/site-packages/apex-0.1-py3.7.egg/apex/init.py", line 27, in
File "", line 983, in _find_and_load
File "", line 967, in _find_and_load_unlocked
File "", line 668, in _load_unlocked
File "", line 638, in _load_backward_compatible
File "/opt/conda/lib/python3.7/site-packages/apex-0.1-py3.7.egg/apex/transformer/init.py", line 4, in
File "", line 983, in _find_and_load
File "", line 967, in _find_and_load_unlocked
File "", line 668, in _load_unlocked
File "", line 638, in _load_backward_compatible
File "/opt/conda/lib/python3.7/site-packages/apex-0.1-py3.7.egg/apex/transformer/pipeline_parallel/init.py", line 1, in
# -- coding: utf-8 --
File "", line 983, in _find_and_load
File "", line 967, in _find_and_load_unlocked
File "", line 668, in _load_unlocked
File "", line 638, in _load_backward_compatible
File "/opt/conda/lib/python3.7/site-packages/apex-0.1-py3.7.egg/apex/transformer/pipeline_parallel/schedules/init.py", line 3, in
File "", line 983, in _find_and_load
File "", line 967, in _find_and_load_unlocked
File "", line 668, in _load_unlocked
File "", line 638, in _load_backward_compatible
File "/opt/conda/lib/python3.7/site-packages/apex-0.1-py3.7.egg/apex/transformer/pipeline_parallel/schedules/fwd_bwd_no_pipelining.py", line 10, in
File "", line 983, in _find_and_load
File "", line 967, in _find_and_load_unlocked
File "", line 668, in _load_unlocked
File "", line 638, in _load_backward_compatible
File "/opt/conda/lib/python3.7/site-packages/apex-0.1-py3.7.egg/apex/transformer/pipeline_parallel/schedules/common.py", line 9, in
File "", line 983, in _find_and_load
File "", line 967, in _find_and_load_unlocked
File "", line 668, in _load_unlocked
File "", line 638, in _load_backward_compatible
File "/opt/conda/lib/python3.7/site-packages/apex-0.1-py3.7.egg/apex/transformer/pipeline_parallel/p2p_communication.py", line 25, in
File "", line 983, in _find_and_load
File "", line 967, in _find_and_load_unlocked
File "", line 668, in _load_unlocked
File "", line 638, in _load_backward_compatible
File "/opt/conda/lib/python3.7/site-packages/apex-0.1-py3.7.egg/apex/transformer/utils.py", line 11, in
AttributeError: module 'torch.distributed' has no attribute '_all_gather_base'

Environment：
Python 3.7.6
torch 1.7.1+cu110
torchaudio 0.7.2
torchvision 0.8.2+cu110
apex 0.1
mmcv-full 1.2.4
mmdet 2.11.0 /root/Swin-Transformer-Object-Detection-master/Swin-Transformer-Object-Detection

Installation method:
Apex Installation method:
git clone https://github.com/NVIDIA/apex
cd apex
pip install -v --disable-pip-version-check --no-cache-dir ./

MMCV Installation method:
pip install mmcv-full==1.2.4 -f https://download.openmmlab.com/mmcv/dist/cu110/torch1.7/index.html

mmdet Installation method:
git clone https://github.com/SwinTransformer/Swin-Transformer-Object-Detection.git
cd Swin-Transformer-Object-Detection
python setup.py develop

[f2367976412]

I also encountered the same problem, please tell me if you solved it

[JankinHou]

我也遇到了同样的问题，请问最终解决了吗？