fix no random bug (#2531)

* test=develop fix no random bug

PaddleCV/object_detection/ppdet/modeling/target_assigners.py

@@ -26,8 +26,7 @@ __all__ = ['BBoxAssigner', 'MaskAssigner', 'CascadeBBoxAssigner']
 
 @register
 class CascadeBBoxAssigner(object):
-    def __init__(
-            self,
+    def __init__(self,
                  batch_size_per_im=512,
                  fg_fraction=.25,
                  fg_thresh=[0.5, 0.6, 0.7],
@@ -35,7 +34,7 @@ class CascadeBBoxAssigner(object):
                  bg_thresh_lo=[0., 0., 0.],
                  bbox_reg_weights=[10, 20, 30],
                  num_classes=81,
-            shuffle_before_sample=True, ):
+                 shuffle_before_sample=True):
         super(CascadeBBoxAssigner, self).__init__()
         self.batch_size_per_im = batch_size_per_im
         self.fg_fraction = fg_fraction
@@ -65,8 +64,8 @@ class CascadeBBoxAssigner(object):
             bg_thresh_hi=self.bg_thresh_hi[curr_stage],
             bg_thresh_lo=self.bg_thresh_lo[curr_stage],
             bbox_reg_weights=curr_bbox_reg_w,
-            use_random=False,
+            use_random=self.use_random,
             class_nums=2,
             is_cls_agnostic=True,
-            is_cascade_rcnn=True if curr_stage > 0 else False, )
+            is_cascade_rcnn=True if curr_stage > 0 else False)
         return outs