Add support for space delimited multi-label targets (#1076)

CHANGELOG.md

@@ -8,6 +8,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 ### Added
 
+- Added support for multi-label, space delimited, targets ([#1076](https://github.com/PyTorchLightning/lightning-flash/pull/1076))
+
 ### Changed
 
 ### Deprecated

flash/core/data/utilities/classification.py

@@ -36,12 +36,17 @@ def _as_list(x: Union[List, torch.Tensor, np.ndarray]) -> List:
     return x
 
 
+def _strip(x: str) -> str:
+    return x.strip(", ")
+
+
 class TargetMode(Enum):
     """The ``TargetMode`` Enum describes the different supported formats for targets in Flash."""
 
     MULTI_TOKEN = auto()
     MULTI_NUMERIC = auto()
     MUTLI_COMMA_DELIMITED = auto()
+    MUTLI_SPACE_DELIMITED = auto()
     MULTI_BINARY = auto()
 
     SINGLE_TOKEN = auto()
@@ -67,9 +72,12 @@ def from_target(cls, target: Any) -> "TargetMode":
             target: A target that is one of: a single target, a list of targets, a comma delimited string.
         """
         if isinstance(target, str):
-            # TODO: This could be a dangerous assumption if people happen to have a label that contains a comma
+            target = _strip(target)
+            # TODO: This could be a dangerous assumption if people happen to have a label that contains a comma or space
             if "," in target:
                 return TargetMode.MUTLI_COMMA_DELIMITED
+            elif " " in target:
+                return TargetMode.MUTLI_SPACE_DELIMITED
             else:
                 return TargetMode.SINGLE_TOKEN
         elif _is_list_like(target):
@@ -88,6 +96,7 @@ def multi_label(self) -> bool:
         return any(
             [
                 self is TargetMode.MUTLI_COMMA_DELIMITED,
+                self is TargetMode.MUTLI_SPACE_DELIMITED,
                 self is TargetMode.MULTI_NUMERIC,
                 self is TargetMode.MULTI_TOKEN,
                 self is TargetMode.MULTI_BINARY,
@@ -116,7 +125,7 @@ def binary(self) -> bool:
 _RESOLUTION_MAPPING = {
     TargetMode.MULTI_BINARY: [TargetMode.MULTI_NUMERIC],
     TargetMode.SINGLE_BINARY: [TargetMode.MULTI_BINARY, TargetMode.MULTI_NUMERIC],
-    TargetMode.SINGLE_TOKEN: [TargetMode.MUTLI_COMMA_DELIMITED],
+    TargetMode.SINGLE_TOKEN: [TargetMode.MUTLI_COMMA_DELIMITED, TargetMode.MUTLI_SPACE_DELIMITED],
     TargetMode.SINGLE_NUMERIC: [TargetMode.MULTI_NUMERIC],
 }
 
@@ -179,7 +188,7 @@ def __init__(self, labels: List[Any]):
         self.label_to_idx = {label: idx for idx, label in enumerate(labels)}
 
     def format(self, target: Any) -> Any:
-        return self.label_to_idx[(target[0] if not isinstance(target, str) else target).strip()]
+        return self.label_to_idx[_strip(target[0] if not isinstance(target, str) else target)]
 
 
 class MultiLabelTargetFormatter(SingleLabelTargetFormatter):
@@ -201,6 +210,11 @@ def format(self, target: Any) -> Any:
         return super().format(target.split(","))
 
 
+class SpaceDelimitedTargetFormatter(MultiLabelTargetFormatter):
+    def format(self, target: Any) -> Any:
+        return super().format(target.split(" "))
+
+
 class MultiNumericTargetFormatter(TargetFormatter):
     def __init__(self, num_classes: int):
         self.num_classes = num_classes
@@ -245,6 +259,8 @@ def get_target_formatter(
         return SingleLabelTargetFormatter(labels)
     elif target_mode is TargetMode.MUTLI_COMMA_DELIMITED:
         return CommaDelimitedTargetFormatter(labels)
+    elif target_mode is TargetMode.MUTLI_SPACE_DELIMITED:
+        return SpaceDelimitedTargetFormatter(labels)
     return MultiLabelTargetFormatter(labels)
 
 
@@ -289,13 +305,16 @@ def get_target_details(targets: List[Any], target_mode: TargetMode) -> Tuple[Opt
         if target_mode is TargetMode.MUTLI_COMMA_DELIMITED:
             for target in targets:
                 tokens.extend(target.split(","))
+        elif target_mode is TargetMode.MUTLI_SPACE_DELIMITED:
+            for target in targets:
+                tokens.extend(target.split(" "))
         elif target_mode is TargetMode.MULTI_TOKEN:
             for target in targets:
                 tokens.extend(target)
         else:
             tokens = targets
 
-        tokens = [token.strip() for token in tokens]
+        tokens = [_strip(token) for token in tokens]
         labels = list(sorted_alphanumeric(set(tokens)))
         num_classes = len(labels)
     return labels, num_classes

flash/image/detection/data.py

@@ -151,9 +151,10 @@ def from_voc(
         transform_kwargs: Optional[Dict] = None,
         **data_module_kwargs: Any,
     ) -> "ObjectDetectionData":
-        """Creates a :class:`~flash.image.detection.data.ObjectDetectionData` object from the given data folders
-        and annotation files in the `PASCAL VOC (Visual Obect Challenge)
-        <http://host.robots.ox.ac.uk/pascal/VOC/>`_ XML format.
+        """.. _PASCAL: http://host.robots.ox.ac.uk/pascal/VOC/
+
+        Creates a :class:`~flash.image.detection.data.ObjectDetectionData` object from the given data folders
+        and annotation files in the `PASCAL VOC (Visual Object Challenge) XML format <PASCAL>`_.
 
         Args:
             train_folder: The folder containing the train data.

tests/core/data/utilities/test_classification.py

@@ -50,6 +50,13 @@
         ["blue", "green", "red"],
         3,
     ),
+    Case(
+        ["blue green", "green red", "red blue"],
+        [[1, 1, 0], [0, 1, 1], [1, 0, 1]],
+        TargetMode.MUTLI_SPACE_DELIMITED,
+        ["blue", "green", "red"],
+        3,
+    ),
     # Ambiguous
     Case([[0], [1, 2], [2, 0]], [[1, 0, 0], [0, 1, 1], [1, 0, 1]], TargetMode.MULTI_NUMERIC, None, 3),
     Case([[1, 0, 0], [0, 1, 1], [1, 0, 1]], [[1, 0, 0], [0, 1, 1], [1, 0, 1]], TargetMode.MULTI_BINARY, None, 3),
@@ -67,6 +74,13 @@
         ["blue", "green", "red"],
         3,
     ),
+    Case(
+        ["blue", "green red", "red blue"],
+        [[1, 0, 0], [0, 1, 1], [1, 0, 1]],
+        TargetMode.MUTLI_SPACE_DELIMITED,
+        ["blue", "green", "red"],
+        3,
+    ),
     # Special cases
     Case(["blue ", " green", "red"], [0, 1, 2], TargetMode.SINGLE_TOKEN, ["blue", "green", "red"], 3),
     Case(
@@ -76,6 +90,13 @@
         ["blue", "green", "red"],
         3,
     ),
+    Case(
+        ["blue", "green ,red", "red ,blue"],
+        [[1, 0, 0], [0, 1, 1], [1, 0, 1]],
+        TargetMode.MUTLI_COMMA_DELIMITED,
+        ["blue", "green", "red"],
+        3,
+    ),
     Case(
         [f"class_{i}" for i in range(10000)],
         list(range(10000)),
@@ -115,16 +136,16 @@ def test_speed(case):
     else:
         targets = case.target * repeats
 
-    start = time.time()
+    start = time.perf_counter()
     target_mode = get_target_mode(targets)
     labels, num_classes = get_target_details(targets, target_mode)
     formatter = get_target_formatter(target_mode, labels, num_classes)
-    end = time.time()
+    end = time.perf_counter()
 
     assert (end - start) / len(targets) < 1e-5  # 0.01ms per target
 
-    start = time.time()
+    start = time.perf_counter()
     _ = [formatter(t) for t in targets]
-    end = time.time()
+    end = time.perf_counter()
 
     assert (end - start) / len(targets) < 1e-5  # 0.01ms per target