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from typing import Any, Callable, Optional, Tuple |
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import torch |
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from .. import transforms |
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from .vision import VisionDataset |
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class FakeData(VisionDataset): |
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"""A fake dataset that returns randomly generated images and returns them as PIL images |
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Args: |
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size (int, optional): Size of the dataset. Default: 1000 images |
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image_size(tuple, optional): Size if the returned images. Default: (3, 224, 224) |
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num_classes(int, optional): Number of classes in the dataset. Default: 10 |
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transform (callable, optional): A function/transform that takes in a PIL image |
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and returns a transformed version. E.g, ``transforms.RandomCrop`` |
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target_transform (callable, optional): A function/transform that takes in the |
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target and transforms it. |
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random_offset (int): Offsets the index-based random seed used to |
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generate each image. Default: 0 |
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""" |
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def __init__( |
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self, |
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size: int = 1000, |
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image_size: Tuple[int, int, int] = (3, 224, 224), |
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num_classes: int = 10, |
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transform: Optional[Callable] = None, |
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target_transform: Optional[Callable] = None, |
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random_offset: int = 0, |
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) -> None: |
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super().__init__(transform=transform, target_transform=target_transform) |
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self.size = size |
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self.num_classes = num_classes |
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self.image_size = image_size |
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self.random_offset = random_offset |
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def __getitem__(self, index: int) -> Tuple[Any, Any]: |
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""" |
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Args: |
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index (int): Index |
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Returns: |
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tuple: (image, target) where target is class_index of the target class. |
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""" |
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if index >= len(self): |
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raise IndexError(f"{self.__class__.__name__} index out of range") |
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rng_state = torch.get_rng_state() |
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torch.manual_seed(index + self.random_offset) |
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img = torch.randn(*self.image_size) |
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target = torch.randint(0, self.num_classes, size=(1,), dtype=torch.long)[0] |
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torch.set_rng_state(rng_state) |
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img = transforms.ToPILImage()(img) |
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if self.transform is not None: |
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img = self.transform(img) |
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if self.target_transform is not None: |
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target = self.target_transform(target) |
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return img, target.item() |
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def __len__(self) -> int: |
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return self.size |
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