Update loss.py

nets/loss.py

@@ -7,7 +7,7 @@ from nets.ious import box_ciou
 #   平滑标签
 #---------------------------------------------------#
 def _smooth_labels(y_true, label_smoothing):
-    num_classes = K.shape(y_true)[-1]
+    num_classes = tf.cast(K.shape(y_true)[-1], dtype=K.floatx())
     label_smoothing = K.constant(label_smoothing, dtype=K.floatx())
     return y_true * (1.0 - label_smoothing) + label_smoothing / num_classes
 #---------------------------------------------------#