apex is not installed AttributeError: module 'torch.distributed' has no attribute '_reduce_scatter_base'

[QY1994-0919]

python tools/train.py --config configs/swin/mask_rcnn_swin_small_patch4_window7_mstrain_480-800_adamw_3x_coco.py --cfg-options model.pretrained=weights/swin_base_patch4_window7_224.pth
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 "/opt/data/private/Models_ours/Swin-Transformer-OD/mmdet/apis/init.py", line 1, in
from .inference import (async_inference_detector, inference_detector,
File "/opt/data/private/Models_ours/Swin-Transformer-OD/mmdet/apis/inference.py", line 11, in
from mmdet.datasets import replace_ImageToTensor
File "/opt/data/private/Models_ours/Swin-Transformer-OD/mmdet/datasets/init.py", line 10, in
from .utils import (NumClassCheckHook, get_loading_pipeline,
File "/opt/data/private/Models_ours/Swin-Transformer-OD/mmdet/datasets/utils.py", line 9, in
from mmdet.models.dense_heads import GARPNHead, RPNHead
File "/opt/data/private/Models_ours/Swin-Transformer-OD/mmdet/models/init.py", line 1, in
from .backbones import * # noqa: F401,F403
File "/opt/data/private/Models_ours/Swin-Transformer-OD/mmdet/models/backbones/init.py", line 13, in
from .swin_transformer import SwinTransformer
File "/opt/data/private/Models_ours/Swin-Transformer-OD/mmdet/models/backbones/swin_transformer.py", line 13, in
from timm.models.layers import DropPath, to_2tuple, trunc_normal_
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/timm/init.py", line 2, in
from .models import create_model, list_models, is_model, list_modules, model_entrypoint,
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/timm/models/init.py", line 1, in
from .beit import *
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/timm/models/beit.py", line 49, in
from timm.data import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/timm/data/init.py", line 5, in
from .dataset import ImageDataset, IterableImageDataset, AugMixDataset
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/timm/data/dataset.py", line 12, in
from .parsers import create_parser
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/timm/data/parsers/init.py", line 1, in
from .parser_factory import create_parser
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/timm/data/parsers/parser_factory.py", line 3, in
from .parser_image_folder import ParserImageFolder
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/timm/data/parsers/parser_image_folder.py", line 11, in
from timm.utils.misc import natural_key
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/timm/utils/init.py", line 4, in
from .cuda import ApexScaler, NativeScaler
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/timm/utils/cuda.py", line 8, in
from apex import amp
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/apex/init.py", line 27, in
from . import transformer
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/apex/transformer/init.py", line 4, in
from apex.transformer import pipeline_parallel
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/apex/transformer/pipeline_parallel/init.py", line 1, in
from apex.transformer.pipeline_parallel.schedules import get_forward_backward_func
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/apex/transformer/pipeline_parallel/schedules/init.py", line 3, in
from apex.transformer.pipeline_parallel.schedules.fwd_bwd_no_pipelining import (
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/apex/transformer/pipeline_parallel/schedules/fwd_bwd_no_pipelining.py", line 10, in
from apex.transformer.pipeline_parallel.schedules.common import Batch
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/apex/transformer/pipeline_parallel/schedules/common.py", line 14, in
from apex.transformer.tensor_parallel.layers import (
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/apex/transformer/tensor_parallel/init.py", line 21, in
from apex.transformer.tensor_parallel.layers import (
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/apex/transformer/tensor_parallel/layers.py", line 32, in
from apex.transformer.tensor_parallel.mappings import (
File "/root/anaconda3/envs/torch19/lib/python3.8/site-packages/apex/transformer/tensor_parallel/mappings.py", line 29, in
torch.distributed.reduce_scatter_tensor = torch.distributed._reduce_scatter_base
AttributeError: module 'torch.distributed' has no attribute '_reduce_scatter_base'