warning when YOLOv3Loss.batch_size setting (#1475)

* warning when YOLOv3Loss.batch_size setting

ppdet/modeling/losses/yolo_loss.py

@@ -23,6 +23,9 @@ try:
 except Exception:
     from collections import Sequence
 
+import logging
+logger = logging.getLogger(__name__)
+
 __all__ = ['YOLOv3Loss']
 
 
@@ -44,7 +47,7 @@ class YOLOv3Loss(object):
     def __init__(
             self,
             train_batch_size=8,
-            batch_size=8,  # stub for backward compatable
+            batch_size=-1,  # stub for backward compatable
             ignore_thresh=0.7,
             label_smooth=True,
             use_fine_grained_loss=False,
@@ -63,6 +66,11 @@ class YOLOv3Loss(object):
         self.scale_x_y = scale_x_y
         self.match_score = match_score
 
+        if batch_size != -1:
+            logger.warn(
+                "config YOLOv3Loss.batch_size is deprecated, "
+                "training batch size should be set by TrainReader.batch_size")
+
     def __call__(self, outputs, gt_box, gt_label, gt_score, targets, anchors,
                  anchor_masks, mask_anchors, num_classes, prefix_name):
         if self._use_fine_grained_loss: