Add GTSRB dataset to prototypes

test/builtin_dataset_mocks.py

@@ -1017,6 +1017,76 @@ def fer2013(info, root, config):
     return num_samples
 
 
+@DATASET_MOCKS.set_from_named_callable
+def gtsrb(info, root, config):
+    num_examples_per_class = 5 if config.split == "train" else 3
+    classes = ("00000", "00042", "00012")
+    num_examples = num_examples_per_class * len(classes)
+
+    csv_columns = ["Filename", "Width", "Height", "Roi.X1", "Roi.Y1", "Roi.X2", "Roi.Y2", "ClassId"]
+
+    def _make_ann_file(path, num_examples, class_idx):
+        if class_idx == "random":
+            class_idx = torch.randint(1, len(classes) + 1, size=(1,)).item()
+
+        with open(path, "w") as csv_file:
+            writer = csv.DictWriter(csv_file, fieldnames=csv_columns, delimiter=";")
+            writer.writeheader()
+            for image_idx in range(num_examples):
+                writer.writerow(
+                    {
+                        "Filename": f"{image_idx:05d}.ppm",
+                        "Width": torch.randint(1, 100, size=()).item(),
+                        "Height": torch.randint(1, 100, size=()).item(),
+                        "Roi.X1": torch.randint(1, 100, size=()).item(),
+                        "Roi.Y1": torch.randint(1, 100, size=()).item(),
+                        "Roi.X2": torch.randint(1, 100, size=()).item(),
+                        "Roi.Y2": torch.randint(1, 100, size=()).item(),
+                        "ClassId": class_idx,
+                    }
+                )
+
+    if config["split"] == "train":
+        train_folder = root / "GTSRB" / "Training"
+        train_folder.mkdir(parents=True)
+
+        for class_idx in classes:
+            create_image_folder(
+                train_folder,
+                name=class_idx,
+                file_name_fn=lambda image_idx: f"{class_idx}_{image_idx:05d}.ppm",
+                num_examples=num_examples_per_class,
+            )
+            _make_ann_file(
+                path=train_folder / class_idx / f"GT-{class_idx}.csv",
+                num_examples=num_examples_per_class,
+                class_idx=int(class_idx),
+            )
+        make_zip(root, "GTSRB-Training_fixed.zip", train_folder)
+    else:
+        test_folder = root / "GTSRB" / "Final_Test"
+        test_folder.mkdir(parents=True)
+
+        create_image_folder(
+            test_folder,
+            name="Images",
+            file_name_fn=lambda image_idx: f"{image_idx:05d}.ppm",
+            num_examples=num_examples,
+        )
+
+        make_zip(root, "GTSRB_Final_Test_Images.zip", test_folder)
+
+        _make_ann_file(
+            path=root / "GT-final_test.csv",
+            num_examples=num_examples,
+            class_idx="random",
+        )
+
+        make_zip(root, "GTSRB_Final_Test_GT.zip", "GT-final_test.csv")
+
+    return num_examples
+
+
 @DATASET_MOCKS.set_from_named_callable
 def clevr(info, root, config):
     data_folder = root / "CLEVR_v1.0"

test/test_prototype_builtin_datasets.py

@@ -123,7 +123,7 @@ def scan(graph):
             if type(dp) is annotation_dp_type:
                 break
         else:
-            raise AssertionError(f"The dataset doesn't comprise a {annotation_dp_type.__name__}() datapipe.")
+            raise AssertionError(f"The dataset doesn't contain a {annotation_dp_type.__name__}() datapipe.")
 
 
 @parametrize_dataset_mocks(DATASET_MOCKS["qmnist"])

torchvision/prototype/datasets/_builtin/README.md

@@ -1,14 +1,22 @@
 # How to add new built-in prototype datasets
 
-As the name implies, the datasets are still in a prototype state and thus subject to rapid change. This in turn means that this document will also change a lot.
+As the name implies, the datasets are still in a prototype state and thus
+subject to rapid change. This in turn means that this document will also change
+a lot.
 
-If you hit a blocker while adding a dataset, please have a look at another similar dataset to see how it is implemented there. If you can't resolve it yourself, feel free to send a draft PR in order for us to help you out. 
+If you hit a blocker while adding a dataset, please have a look at another
+similar dataset to see how it is implemented there. If you can't resolve it
+yourself, feel free to send a draft PR in order for us to help you out.
 
 Finally, `from torchvision.prototype import datasets` is implied below.
 
 ## Implementation
 
-Before we start with the actual implementation, you should create a module in `torchvision/prototype/datasets/_builtin` that hints at the dataset you are going to add. For example `caltech.py` for `caltech101` and `caltech256`. In that module create a class that inherits from `datasets.utils.Dataset` and overwrites at minimum three methods that will be discussed in detail below:
+Before we start with the actual implementation, you should create a module in
+`torchvision/prototype/datasets/_builtin` that hints at the dataset you are
+going to add. For example `caltech.py` for `caltech101` and `caltech256`. In
+that module create a class that inherits from `datasets.utils.Dataset` and
+overwrites at minimum three methods that will be discussed in detail below:
 
 ```python
 import io
@@ -37,27 +45,54 @@ class MyDataset(Dataset):
 
 ### `_make_info(self)`
 
-The `DatasetInfo` carries static information about the dataset. There are two required fields:
-- `name`: Name of the dataset. This will be used to load the dataset with `datasets.load(name)`. Should only contain lower characters.
-- `type`: Field of the `datasets.utils.DatasetType` enum. This is used to select the default decoder in case the user doesn't pass one. There are currently only two options: `IMAGE` and `RAW` ([see below](what-is-the-datasettyperaw-and-when-do-i-use-it) for details).
+The `DatasetInfo` carries static information about the dataset. There are two
+required fields:
+- `name`: Name of the dataset. This will be used to load the dataset with
+  `datasets.load(name)`. Should only contain lowercase characters.
+- `type`: Field of the `datasets.utils.DatasetType` enum. This is used to select
+   the default decoder in case the user doesn't pass one. There are currently
+   only two options: `IMAGE` and `RAW` ([see
+   below](what-is-the-datasettyperaw-and-when-do-i-use-it) for details).
 
 There are more optional parameters that can be passed:
 
-- `dependencies`: Collection of third-party dependencies that are needed to load the dataset, e.g. `("scipy",)`. Their availability will be automatically checked if a user tries to load the dataset. Within the implementation, import these packages lazily to avoid missing dependencies at import time.
-- `categories`: Sequence of human-readable category names for each label. The index of each category has to match the corresponding label returned in the dataset samples. [See below](#how-do-i-handle-a-dataset-that-defines-many-categories) how to handle cases with many categories.
-- `valid_options`: Configures valid options that can be passed to the dataset. It should be `Dict[str, Sequence[str]]`. The options are accessible through the `config` namespace in the other two functions. First value of the sequence is taken as default if the user passes no option to `torchvision.prototype.datasets.load()`.
+- `dependencies`: Collection of third-party dependencies that are needed to load
+  the dataset, e.g. `("scipy",)`. Their availability will be automatically
+  checked if a user tries to load the dataset. Within the implementation, import
+  these packages lazily to avoid missing dependencies at import time.
+- `categories`: Sequence of human-readable category names for each label. The
+  index of each category has to match the corresponding label returned in the
+  dataset samples. [See
+  below](#how-do-i-handle-a-dataset-that-defines-many-categories) how to handle
+  cases with many categories.
+- `valid_options`: Configures valid options that can be passed to the dataset.
+  It should be `Dict[str, Sequence[Any]]`. The options are accessible through
+  the `config` namespace in the other two functions. First value of the sequence
+  is taken as default if the user passes no option to
+  `torchvision.prototype.datasets.load()`.
 
 ## `resources(self, config)`
 
-Returns `List[datasets.utils.OnlineResource]` of all the files that need to be present locally before the dataset with a specific `config` can be build. The download will happen automatically. 
+Returns `List[datasets.utils.OnlineResource]` of all the files that need to be
+present locally before the dataset with a specific `config` can be build. The
+download will happen automatically. 
 
 Currently, the following `OnlineResource`'s are supported:
 
-- `HttpResource`: Used for files that are directly exposed through HTTP(s) and only requires the URL.
-- `GDriveResource`: Used for files that are hosted on GDrive and requires the GDrive ID as well as the `file_name`.
-- `ManualDownloadResource`: Used files are not publicly accessible and requires instructions how to download them manually. If the file does not exist, an error will be raised with the supplied instructions.
-
-Although optional in general, all resources used in the built-in datasets should comprise [SHA256](https://en.wikipedia.org/wiki/SHA-2) checksum for security. It will be automatically checked after the download. You can compute the checksum with system utilities or this snippet:
+- `HttpResource`: Used for files that are directly exposed through HTTP(s) and
+  only requires the URL.
+- `GDriveResource`: Used for files that are hosted on GDrive and requires the
+  GDrive ID as well as the `file_name`.
+- `ManualDownloadResource`: Used files are not publicly accessible and requires
+  instructions how to download them manually. If the file does not exist, an
+  error will be raised with the supplied instructions.
+- `KaggleDownloadResource`: Used for files that are available on Kaggle. This
+  inherits from `ManualDownloadResource`.
+
+Although optional in general, all resources used in the built-in datasets should
+comprise [SHA256](https://en.wikipedia.org/wiki/SHA-2) checksum for security. It
+will be automatically checked after the download. You can compute the checksum
+with system utilities e.g `sha256-sum`, or this snippet:
 
 ```python
 import hashlib
@@ -72,35 +107,84 @@ def sha256sum(path, chunk_size=1024 * 1024):
 
 ### `_make_datapipe(resource_dps, *, config, decoder)`
 
-This method is the heart of the dataset that need to transform the raw data into a usable form. A major difference compared to the current stable datasets is that everything is performed through `IterDataPipe`'s. From the perspective of someone that is working with them rather than on them, `IterDataPipe`'s behave just as generators, i.e. you can't do anything with them besides iterating. 
+This method is the heart of the dataset, where we transform the raw data into
+a usable form. A major difference compared to the current stable datasets is
+that everything is performed through `IterDataPipe`'s. From the perspective of
+someone that is working with them rather than on them, `IterDataPipe`'s behave
+just as generators, i.e. you can't do anything with them besides iterating.
 
-Of course, there are some common building blocks that should suffice in 95% of the cases. The most used 
+Of course, there are some common building blocks that should suffice in 95% of
+the cases. The most used are:
 
 - `Mapper`: Apply a callable to every item in the datapipe. 
 - `Filter`: Keep only items that satisfy a condition.
 - `Demultiplexer`: Split a datapipe into multiple ones.
 - `IterKeyZipper`: Merge two datapipes into one.
 
-All of them can be imported `from torchdata.datapipes.iter`. In addition, use `functools.partial` in case a callable needs extra arguments.  If the provided `IterDataPipe`'s are not sufficient for the use case, it is also not complicated to add one. See the MNIST or CelebA datasets for example.
+All of them can be imported `from torchdata.datapipes.iter`. In addition, use
+`functools.partial` in case a callable needs extra arguments.  If the provided
+`IterDataPipe`'s are not sufficient for the use case, it is also not complicated
+to add one. See the MNIST or CelebA datasets for example.
+
+`make_datapipe()` receives `resource_dps`, which is a list of datapipes that has
+a 1-to-1 correspondence with the return value of `resources()`. In case of
+archives with regular suffixes (`.tar`, `.zip`, ...), the datapipe will contain
+tuples comprised of the path and the handle for every file in the archive.
+Otherwise the datapipe will only contain one of such tuples for the file
+specified by the resource.
+
+Since the datapipes are iterable in nature, some datapipes feature an in-memory
+buffer, e.g. `IterKeyZipper` and `Grouper`. There are two issues with that: 1.
+If not used carefully, this can easily overflow the host memory, since most
+datasets will not fit in completely. 2. This can lead to unnecessarily long
+warm-up times when data is buffered that is only needed at runtime.
+
+Thus, all buffered datapipes should be used as early as possible, e.g. zipping
+two datapipes of file handles rather than trying to zip already loaded images.
+
+There are two special datapipes that are not used through their class, but
+through the functions `hint_sharding` and `hint_shuffling`. As the name implies
+they only hint part in the datapipe graph where sharding and shuffling should
+take place, but are no-ops by default. They can be imported from
+`torchvision.prototype.datasets.utils._internal` and are required in each
+dataset.
+
+Finally, each item in the final datapipe should be a dictionary with `str` keys.
+There is no standardization of the names (yet!).
 
-`make_datapipe()` receives `resource_dps`, which is a list of datapipes that has a 1-to-1 correspondence with the return value of `resources()`. In case of archives with regular suffixes (`.tar`, `.zip`, ...), the datapipe will contain tuples comprised of the path and the handle for every file in the archive. Otherwise the datapipe will only contain one of such tuples for the file specified by the resource.
+## FAQ
 
-Since the datapipes are iterable in nature, some datapipes feature an in-memory buffer, e.g. `IterKeyZipper` and `Grouper`. There are two issues with that:
-1. If not used carefully, this can easily overflow the host memory, since most datasets will not fit in completely.
-2. This can lead to unnecessarily long warm-up times when data is buffered that is only needed at runtime.
+### How do I start?
 
-Thus, all buffered datapipes should be used as early as possible, e.g. zipping two datapipes of file handles rather than trying to zip already loaded images.
+Get the skeleton of your dataset class ready with all 3 methods. For
+`_make_datapipe()`, you can just do `return resources_dp[0]` to get started.
+Then import the dataset class in
+`torchvision/prototype/datasets/_builtin/__init__.py`: this will automatically
+register the dataset and it will be instantiable via
+`datasets.load("mydataset")`. On a separate script, try something like
 
-There are two special datapipes that are not used through their class, but through the functions `hint_sharding` and `hint_shuffling`. As the name implies they only hint part in the datapipe graph where sharding and shuffling should take place, but are no-ops by default. They can be imported from `torchvision.prototype.datasets.utils._internal` and are required in each dataset.
+```py
+from torchvision.prototype import datasets
 
-Finally, each item in the final datapipe should be a dictionary with `str` keys. There is no standardization of the names (yet!).
+dataset = datasets.load("mydataset")
+for sample in dataset:
+    print(sample)  # this is the content of an item in datapipe returned by _make_datapipe()
+    break
+# Or you can also inspect the sample in a debugger
+```
 
-## FAQ
+This will give you an idea of what the first datapipe in `resources_dp`
+contains. You can also do that with `resources_dp[1]` or `resources_dp[2]`
+(etc.) if they exist. Then follow the instructions above to manipulate these
+datapipes and return the appropriate dictionary format.
 
 ### What is the `DatasetType.RAW` and when do I use it?
 
-`DatasetType.RAW` marks dataset that provides decoded, i.e. raw pixel values, rather than encoded image files such as 
-`.jpg` or `.png`. This is usually only the case for small datasets, since it requires a lot more disk space. The default decoder `datasets.decoder.raw` is only a sentinel and should not be called directly. The decoding should look something like 
+`DatasetType.RAW` marks dataset that provides decoded, i.e. raw pixel values,
+rather than encoded image files such as `.jpg` or `.png`. This is usually only
+the case for small datasets, since it requires a lot more disk space. The
+default decoder `datasets.decoder.raw` is only a sentinel and should not be
+called directly. The decoding should look something like
 
 ```python
 from torchvision.prototype.datasets.decoder import raw
@@ -118,10 +202,28 @@ For examples, have a look at the MNIST, CIFAR, or SEMEION datasets.
 
 ### How do I handle a dataset that defines many categories?
 
-As a rule of thumb, `datasets.utils.DatasetInfo(..., categories=)` should only be set directly for ten categories or fewer. If more categories are needed, you can add a `$NAME.categories` file to the `_builtin` folder in which each line specifies a category. If `$NAME` matches the name of the dataset (which it definitively should!) it will be automatically loaded if `categories=` is not set.
-
-In case the categories can be generated from the dataset files, e.g. the dataset follow an image folder approach where each folder denotes the name of the category, the dataset can overwrite the `_generate_categories` method. It gets passed the `root` path to the resources, but they have to be manually loaded, e.g. `self.resources(config)[0].load(root)`. The method should return a sequence of strings representing the category names. To generate the `$NAME.categories` file, run `python -m torchvision.prototype.datasets.generate_category_files $NAME`.
+As a rule of thumb, `datasets.utils.DatasetInfo(..., categories=)` should only
+be set directly for ten categories or fewer. If more categories are needed, you
+can add a `$NAME.categories` file to the `_builtin` folder in which each line
+specifies a category. If `$NAME` matches the name of the dataset (which it
+definitively should!) it will be automatically loaded if `categories=` is not
+set.
+
+In case the categories can be generated from the dataset files, e.g. the dataset
+follows an image folder approach where each folder denotes the name of the
+category, the dataset can overwrite the `_generate_categories` method. It gets
+passed the `root` path to the resources, but they have to be manually loaded,
+e.g. `self.resources(config)[0].load(root)`. The method should return a sequence
+of strings representing the category names. To generate the `$NAME.categories`
+file, run `python -m torchvision.prototype.datasets.generate_category_files
+$NAME`.
 
 ### What if a resource file forms an I/O bottleneck?
 
-In general, we are ok with small performance hits of iterating archives rather than their extracted content. However, if the performance hit becomes significant, the archives can still be decompressed or extracted. To do this, the `decompress: bool` and `extract: bool` flags can be used for every `OnlineResource` individually. For more complex cases, each resource also accepts a `preprocess` callable that gets passed a `pathlib.Path` of the raw file and should return `pathlib.Path` of the preprocessed file or folder.
+In general, we are ok with small performance hits of iterating archives rather
+than their extracted content. However, if the performance hit becomes
+significant, the archives can still be decompressed or extracted. To do this,
+the `decompress: bool` and `extract: bool` flags can be used for every
+`OnlineResource` individually. For more complex cases, each resource also
+accepts a `preprocess` callable that gets passed a `pathlib.Path` of the raw
+file and should return `pathlib.Path` of the preprocessed file or folder.

torchvision/prototype/datasets/_builtin/__init__.py

@@ -6,6 +6,7 @@
 from .cub200 import CUB200
 from .dtd import DTD
 from .fer2013 import FER2013
+from .gtsrb import GTSRB
 from .imagenet import ImageNet
 from .mnist import MNIST, FashionMNIST, KMNIST, EMNIST, QMNIST
 from .oxford_iiit_pet import OxfordIITPet