Migrate Fer2013 prototype dataset (#5759)

* Migrate Fer2013 prototype dataset

* Update torchvision/prototype/datasets/_builtin/fer2013.py

Co-authored-by: Philip Meier <github.pmeier@posteo.de>

Co-authored-by: Philip Meier <github.pmeier@posteo.de>

test/builtin_dataset_mocks.py

@@ -1019,13 +1019,14 @@ def dtd(root, config):
     return num_samples_map[config["split"], config["fold"]]
 
 
-# @register_mock
-def fer2013(info, root, config):
-    num_samples = 5 if config.split == "train" else 3
+@register_mock(configs=combinations_grid(split=("train", "test")))
+def fer2013(root, config):
+    split = config["split"]
+    num_samples = 5 if split == "train" else 3
 
-    path = root / f"{config.split}.csv"
+    path = root / f"{split}.csv"
     with open(path, "w", newline="") as file:
-        field_names = ["emotion"] if config.split == "train" else []
+        field_names = ["emotion"] if split == "train" else []
         field_names.append("pixels")
 
         file.write(",".join(field_names) + "\n")
@@ -1035,7 +1036,7 @@ def fer2013(info, root, config):
             rowdict = {
                 "pixels": " ".join([str(int(pixel)) for pixel in torch.randint(256, (48 * 48,), dtype=torch.uint8)])
             }
-            if config.split == "train":
+            if split == "train":
                 rowdict["emotion"] = int(torch.randint(7, ()))
             writer.writerow(rowdict)
 

torchvision/prototype/datasets/_builtin/fer2013.py

@@ -1,11 +1,10 @@
-from typing import Any, Dict, List, cast
+import pathlib
+from typing import Any, Dict, List, cast, Union
 
 import torch
 from torchdata.datapipes.iter import IterDataPipe, Mapper, CSVDictParser
 from torchvision.prototype.datasets.utils import (
-    Dataset,
-    DatasetConfig,
-    DatasetInfo,
+    Dataset2,
     OnlineResource,
     KaggleDownloadResource,
 )
@@ -15,26 +14,40 @@
 )
 from torchvision.prototype.features import Label, Image
 
+from .._api import register_dataset, register_info
+
+NAME = "fer2013"
+
+
+@register_info(NAME)
+def _info() -> Dict[str, Any]:
+    return dict(categories=("angry", "disgust", "fear", "happy", "sad", "surprise", "neutral"))
 
-class FER2013(Dataset):
-    def _make_info(self) -> DatasetInfo:
-        return DatasetInfo(
-            "fer2013",
-            homepage="https://www.kaggle.com/c/challenges-in-representation-learning-facial-expression-recognition-challenge",
-            categories=("angry", "disgust", "fear", "happy", "sad", "surprise", "neutral"),
-            valid_options=dict(split=("train", "test")),
-        )
+
+@register_dataset(NAME)
+class FER2013(Dataset2):
+    """FER 2013 Dataset
+    homepage="https://www.kaggle.com/c/challenges-in-representation-learning-facial-expression-recognition-challenge"
+    """
+
+    def __init__(
+        self, root: Union[str, pathlib.Path], *, split: str = "train", skip_integrity_check: bool = False
+    ) -> None:
+        self._split = self._verify_str_arg(split, "split", {"train", "test"})
+        self._categories = _info()["categories"]
+
+        super().__init__(root, skip_integrity_check=skip_integrity_check)
 
     _CHECKSUMS = {
         "train": "a2b7c9360cc0b38d21187e5eece01c2799fce5426cdeecf746889cc96cda2d10",
         "test": "dec8dfe8021e30cd6704b85ec813042b4a5d99d81cb55e023291a94104f575c3",
     }
 
-    def resources(self, config: DatasetConfig) -> List[OnlineResource]:
+    def _resources(self) -> List[OnlineResource]:
         archive = KaggleDownloadResource(
-            cast(str, self.info.homepage),
-            file_name=f"{config.split}.csv.zip",
-            sha256=self._CHECKSUMS[config.split],
+            "https://www.kaggle.com/c/challenges-in-representation-learning-facial-expression-recognition-challenge",
+            file_name=f"{self._split}.csv.zip",
+            sha256=self._CHECKSUMS[self._split],
         )
         return [archive]
 
@@ -43,17 +56,15 @@ def _prepare_sample(self, data: Dict[str, Any]) -> Dict[str, Any]:
 
         return dict(
             image=Image(torch.tensor([int(idx) for idx in data["pixels"].split()], dtype=torch.uint8).reshape(48, 48)),
-            label=Label(int(label_id), categories=self.categories) if label_id is not None else None,
+            label=Label(int(label_id), categories=self._categories) if label_id is not None else None,
         )
 
-    def _make_datapipe(
-        self,
-        resource_dps: List[IterDataPipe],
-        *,
-        config: DatasetConfig,
-    ) -> IterDataPipe[Dict[str, Any]]:
+    def _datapipe(self, resource_dps: List[IterDataPipe]) -> IterDataPipe[Dict[str, Any]]:
         dp = resource_dps[0]
         dp = CSVDictParser(dp)
         dp = hint_shuffling(dp)
         dp = hint_sharding(dp)
         return Mapper(dp, self._prepare_sample)
+
+    def __len__(self) -> int:
+        return 28_709 if self._split == "train" else 3_589