enforce random sampling at first call in kornia parallell transforms

CHANGELOG.md

@@ -13,12 +13,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 ### Changed
 
 - Changed the installation command for extra features ([#346](https://github.com/PyTorchLightning/lightning-flash/pull/346))
-
-
 - Fixed a bug where the translation task wasn't decoding tokens properly ([#332](https://github.com/PyTorchLightning/lightning-flash/pull/332))
-
-
 - Fixed a bug where huggingface tokenizers were sometimes being pickled ([#332](https://github.com/PyTorchLightning/lightning-flash/pull/332))
+- Fixed issue with `KorniaParallelTransforms` to assure to share the random state between transforms ([#351](https://github.com/PyTorchLightning/lightning-flash/pull/351))
+- Change resize interpolation default mode to nearest ([#352](https://github.com/PyTorchLightning/lightning-flash/pull/352))
 
 
 ## [0.3.0] - 2021-05-20

flash/core/data/transforms.py

@@ -78,16 +78,21 @@ def forward(self, inputs: Any):
         result = list(inputs) if isinstance(inputs, Sequence) else [inputs]
         for transform in self.children():
             inputs = result
+
+            # we enforce the first time to sample random params
+            result[0] = transform(inputs[0])
+
             if hasattr(transform, "_params") and bool(transform._params):
                 params = transform._params
             else:
                 params = None
 
-            for i, input in enumerate(inputs):
+            # apply transforms from (1, n)
+            for i, input in enumerate(inputs[1:]):
                 if params is not None:
-                    result[i] = transform(input, params)
+                    result[i + 1] = transform(input, params)
                 else:  # case for non random transforms
-                    result[i] = transform(input)
+                    result[i + 1] = transform(input)
             if hasattr(transform, "_params") and bool(transform._params):
                 transform._params = None
         return result

flash/image/segmentation/transforms.py

@@ -38,7 +38,7 @@ def default_transforms(image_size: Tuple[int, int]) -> Dict[str, Callable]:
         "post_tensor_transform": nn.Sequential(
             ApplyToKeys(
                 [DefaultDataKeys.INPUT, DefaultDataKeys.TARGET],
-                KorniaParallelTransforms(K.geometry.Resize(image_size, interpolation='bilinear')),
+                KorniaParallelTransforms(K.geometry.Resize(image_size, interpolation='nearest')),
             ),
         ),
         "collate": Compose([kornia_collate, ApplyToKeys(DefaultDataKeys.TARGET, prepare_target)]),

tests/core/data/test_transforms.py

@@ -97,17 +97,18 @@ def test_kornia_parallel_transforms(with_params):
     transform_b = Mock(spec=torch.nn.Module)
 
     if with_params:
-        transform_a._params = "test"
+        transform_a._params = "test"  # initialize params with some value
 
     parallel_transforms = KorniaParallelTransforms(transform_a, transform_b)
-
     parallel_transforms(samples)
 
     assert transform_a.call_count == 2
     assert transform_b.call_count == 2
 
     if with_params:
-        assert transform_a.call_args_list[0][0][1] == transform_a.call_args_list[1][0][1] == "test"
+        assert transform_a.call_args_list[1][0][1] == "test"
+        # check that after the forward `_params` is set to None
+        assert transform_a._params == transform_a._params is None
 
     assert torch.allclose(transform_a.call_args_list[0][0][0], samples[0])
     assert torch.allclose(transform_a.call_args_list[1][0][0], samples[1])