fix data_layer for 3D data

python/paddle/trainer_config_helpers/layers.py

@@ -929,11 +929,13 @@ def data_layer(name, size, depth=None, height=None, width=None,
         width=width,
         **ExtraLayerAttribute.to_kwargs(layer_attr))
 
+    if depth is None:
+        depth = 1
     num_filters = None
     if height is not None and width is not None:
-        num_filters = size / (width * height)
-        assert num_filters * width * height == size, \
-            "size=%s width=%s height=%s" % (size, width, height)
+        num_filters = size / (width * height * depth)
+        assert num_filters * width * height * depth == size, \
+                "size=%s width=%s height=%s depth=%s"  % (size, width, height, depth)
 
     return LayerOutput(name, LayerType.DATA, size=size, num_filters=num_filters)