Go back to torch's DDP

Apex was having some weird crashing issues.

codes/models/ExtensibleTrainer.py

@@ -3,9 +3,9 @@ import os
 
 import torch
 from apex import amp
-from apex.parallel import DistributedDataParallel
 from torch.nn.parallel import DataParallel
 import torch.nn as nn
+from torch.nn.parallel.distributed import DistributedDataParallel
 
 import models.lr_scheduler as lr_scheduler
 import models.networks as networks
@@ -109,7 +109,9 @@ class ExtensibleTrainer(BaseModel):
         dnets = []
         for anet in amp_nets:
             if opt['dist']:
-                dnet = DistributedDataParallel(anet, delay_allreduce=True)
+                dnet = DistributedDataParallel(anet,
+                                               device_ids=[torch.cuda.current_device()],
+                                               find_unused_parameters=False)
             else:
                 dnet = DataParallel(anet)
             if self.is_train:

codes/models/base_model.py

@@ -2,7 +2,8 @@ import os
 from collections import OrderedDict
 import torch
 import torch.nn as nn
-from apex.parallel import DistributedDataParallel
+from torch.nn.parallel.distributed import DistributedDataParallel
+
 import utils.util
 from apex import amp