fix: only fp16 evaluation is supported when ampO2 is enabled

ppcls/configs/ImageNet/ResNet/ResNet50_amp_O2_ultra.yaml

@@ -24,6 +24,8 @@ AMP:
   use_dynamic_loss_scaling: True
   # O2: pure fp16
   level: O2
+  # only FP16 evaluation is supported when AMP O2 is enabled
+  use_fp16_test: True
 
 # model architecture
 Arch:

ppcls/configs/ImageNet/SENet/SE_ResNeXt101_32x4d_amp_O2_ultra.yaml

@@ -38,6 +38,8 @@ AMP:
     use_dynamic_loss_scaling: True
     # O2: pure fp16
     level: O2
+    # only FP16 evaluation is supported when AMP O2 is enabled
+    use_fp16_test: True
 
 Optimizer:
   name: Momentum

ppcls/engine/evaluation/classification.py

@@ -53,7 +53,7 @@ def classification_eval(engine, epoch_id=0):
             ]
         time_info["reader_cost"].update(time.time() - tic)
         batch_size = batch[0].shape[0]
-        batch[0] = paddle.to_tensor(batch[0]).astype("float32")
+        batch[0] = paddle.to_tensor(batch[0])
         if not engine.config["Global"].get("use_multilabel", False):
             batch[1] = batch[1].reshape([-1, 1]).astype("int64")