Don't force datum.label=0 in array_to_datum

python/caffe/io.py

@@ -63,7 +63,7 @@ def blobprotovector_str_to_arraylist(str):
     return [blobproto_to_array(blob) for blob in vec.blobs]
 
 
-def array_to_datum(arr, label=0):
+def array_to_datum(arr, label=None):
     """Converts a 3-dimensional array to datum. If the array has dtype uint8,
     the output data will be encoded as a string. Otherwise, the output data
     will be stored in float format.
@@ -76,7 +76,8 @@ def array_to_datum(arr, label=0):
         datum.data = arr.tostring()
     else:
         datum.float_data.extend(arr.flat)
-    datum.label = label
+    if label is not None:
+        datum.label = label
     return datum
 
 

python/caffe/test/test_io.py

@@ -39,3 +39,18 @@ def test_scalar(self):
 
         arr = caffe.io.blobproto_to_array(blob)
         self.assertEqual(arr, 123)
+
+
+class TestArrayToDatum(unittest.TestCase):
+
+    def test_label_none_size(self):
+        # Set label
+        d1 = caffe.io.array_to_datum(
+            np.ones((10,10,3)), label=1)
+        # Don't set label
+        d2 = caffe.io.array_to_datum(
+            np.ones((10,10,3)))
+        # Not setting the label should result in a smaller object
+        self.assertGreater(
+            len(d1.SerializeToString()),
+            len(d2.SerializeToString()))