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Source code for torchvision.datasets.fakedata

from typing import Any, Callable, Optional, Tuple

import torch

from .. import transforms
from .vision import VisionDataset


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

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