fix ReID trainer bugs

ppcls/configs/Vehicle/ResNet50_ReID.yaml

@@ -17,6 +17,7 @@ Global:
   image_shape: [3, 224, 224]
   save_inference_dir: "./inference"
   num_split: 1
+  feature_normalize: True
 
 
 # model architecture

ppcls/data/__init__.py

@@ -27,8 +27,7 @@ from ppcls.data.dataloader.common_dataset import create_operators
 from ppcls.data.dataloader.vehicle_dataset import CompCars, VeriWild
 
 # sampler
-from ppcls.data.dataloader import DistributedRandomIdentitySampler
-
+from ppcls.data.dataloader.DistributedRandomIdentitySampler import DistributedRandomIdentitySampler
 from ppcls.data.preprocess import transform
 
 

ppcls/engine/trainer_reid.py

@@ -169,9 +169,11 @@ class TrainerReID(Trainer):
             batch_feas = out["features"]
 
             # do norm
-            feas_norm = paddle.sqrt(
-                paddle.sum(paddle.square(batch_feas), axis=1, keepdim=True))
-            batch_feas = paddle.divide(batch_feas, feas_norm)
+            if self.config["Global"].get("feature_normalize", True):
+                feas_norm = paddle.sqrt(
+                    paddle.sum(paddle.square(batch_feas), axis=1,
+                               keepdim=True))
+                batch_feas = paddle.divide(batch_feas, feas_norm)
 
             batch_feas = batch_feas
             batch_image_labels = batch[1]