[MXNET-664] Support integer type in ImageIter

python/mxnet/image/image.py

@@ -1057,16 +1057,19 @@ class ImageIter(io.DataIter):
         Data name for provided symbols.
     label_name : str
         Label name for provided symbols.
+    dtype : str
+        Label data type. Default: float32. Other options: int32, int64, float64
     kwargs : ...
         More arguments for creating augmenter. See mx.image.CreateAugmenter.
     """
 
     def __init__(self, batch_size, data_shape, label_width=1,
                  path_imgrec=None, path_imglist=None, path_root=None, path_imgidx=None,
                  shuffle=False, part_index=0, num_parts=1, aug_list=None, imglist=None,
-                 data_name='data', label_name='softmax_label', **kwargs):
+                 data_name='data', label_name='softmax_label', dtype='float32', **kwargs):
         super(ImageIter, self).__init__()
         assert path_imgrec or path_imglist or (isinstance(imglist, list))
+        assert dtype in ['int32', 'float32', 'int64', 'float64'], dtype + ' label not supported'
         num_threads = os.environ.get('MXNET_CPU_WORKER_NTHREADS', 1)
         logging.info('Using %s threads for decoding...', str(num_threads))
         logging.info('Set enviroment variable MXNET_CPU_WORKER_NTHREADS to a'
@@ -1091,7 +1094,7 @@ def __init__(self, batch_size, data_shape, label_width=1,
                 imgkeys = []
                 for line in iter(fin.readline, ''):
                     line = line.strip().split('\t')
-                    label = nd.array([float(i) for i in line[1:-1]])
+                    label = nd.array(line[1:-1], dtype=dtype)
                     key = int(line[0])
                     imglist[key] = (label, line[-1])
                     imgkeys.append(key)
@@ -1105,11 +1108,11 @@ def __init__(self, batch_size, data_shape, label_width=1,
                 key = str(index)  # pylint: disable=redefined-variable-type
                 index += 1
                 if len(img) > 2:
-                    label = nd.array(img[:-1])
+                    label = nd.array(img[:-1], dtype=dtype)
                 elif isinstance(img[0], numeric_types):
-                    label = nd.array([img[0]])
+                    label = nd.array([img[0]], dtype=dtype)
                 else:
-                    label = nd.array(img[0])
+                    label = nd.array(img[0], dtype=dtype)
                 result[key] = (label, img[-1])
                 imgkeys.append(str(key))
             self.imglist = result

tests/python/unittest/test_image.py

@@ -132,26 +132,33 @@ def test_color_normalize(self):
 
 
     def test_imageiter(self):
-        im_list = [[np.random.randint(0, 5), x] for x in TestImage.IMAGES]
-        test_iter = mx.image.ImageIter(2, (3, 224, 224), label_width=1, imglist=im_list,
-            path_root='')
-        for _ in range(3):
+        def check_imageiter(dtype='float32'):
+            im_list = [[np.random.randint(0, 5), x] for x in TestImage.IMAGES]
+            test_iter = mx.image.ImageIter(2, (3, 224, 224), label_width=1, imglist=im_list,
+                path_root='', dtype=dtype)
+            for _ in range(3):
+                for batch in test_iter:
+                    pass
+                test_iter.reset()
+
+            # test with list file
+            fname = './data/test_imageiter.lst'
+            file_list = ['\t'.join([str(k), str(np.random.randint(0, 5)), x]) \
+                for k, x in enumerate(TestImage.IMAGES)]
+            with open(fname, 'w') as f:
+                for line in file_list:
+                    f.write(line + '\n')
+
+            test_iter = mx.image.ImageIter(2, (3, 224, 224), label_width=1, path_imglist=fname,
+                path_root='', dtype=dtype)
             for batch in test_iter:
                 pass
-            test_iter.reset()
 
-        # test with list file
-        fname = './data/test_imageiter.lst'
-        file_list = ['\t'.join([str(k), str(np.random.randint(0, 5)), x]) \
-            for k, x in enumerate(TestImage.IMAGES)]
-        with open(fname, 'w') as f:
-            for line in file_list:
-                f.write(line + '\n')
+        for dtype in ['int32', 'float32', 'int64', 'float64']:
+            check_imageiter(dtype)
 
-        test_iter = mx.image.ImageIter(2, (3, 224, 224), label_width=1, path_imglist=fname,
-            path_root='')
-        for batch in test_iter:
-            pass
+        # test with default dtype
+        check_imageiter()
 
     @with_seed()
     def test_augmenters(self):