from __future__ import print_function
import torch.utils.data as data
from PIL import Image
import os
import os.path
import numpy as np
from .utils import download_url, check_integrity
class SVHN(data.Dataset):
"""`SVHN <http://ufldl.stanford.edu/housenumbers/>`_ Dataset.
Note: The SVHN dataset assigns the label `10` to the digit `0`. However, in this Dataset,
we assign the label `0` to the digit `0` to be compatible with PyTorch loss functions which
expect the class labels to be in the range `[0, C-1]`
Args:
root (string): Root directory of dataset where directory
``SVHN`` exists.
split (string): One of {'train', 'test', 'extra'}.
Accordingly dataset is selected. 'extra' is Extra training set.
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.
download (bool, optional): If true, downloads the dataset from the internet and
puts it in root directory. If dataset is already downloaded, it is not
downloaded again.
"""
url = ""
filename = ""
file_md5 = ""
split_list = {
'train': ["http://ufldl.stanford.edu/housenumbers/train_32x32.mat",
"train_32x32.mat", "e26dedcc434d2e4c54c9b2d4a06d8373"],
'test': ["http://ufldl.stanford.edu/housenumbers/test_32x32.mat",
"test_32x32.mat", "eb5a983be6a315427106f1b164d9cef3"],
'extra': ["http://ufldl.stanford.edu/housenumbers/extra_32x32.mat",
"extra_32x32.mat", "a93ce644f1a588dc4d68dda5feec44a7"]}
def __init__(self, root, split='train',
transform=None, target_transform=None, download=False):
self.root = os.path.expanduser(root)
self.transform = transform
self.target_transform = target_transform
self.split = split # training set or test set or extra set
if self.split not in self.split_list:
raise ValueError('Wrong split entered! Please use split="train" '
'or split="extra" or split="test"')
self.url = self.split_list[split][0]
self.filename = self.split_list[split][1]
self.file_md5 = self.split_list[split][2]
if download:
self.download()
if not self._check_integrity():
raise RuntimeError('Dataset not found or corrupted.' +
' You can use download=True to download it')
# import here rather than at top of file because this is
# an optional dependency for torchvision
import scipy.io as sio
# reading(loading) mat file as array
loaded_mat = sio.loadmat(os.path.join(self.root, self.filename))
self.data = loaded_mat['X']
# loading from the .mat file gives an np array of type np.uint8
# converting to np.int64, so that we have a LongTensor after
# the conversion from the numpy array
# the squeeze is needed to obtain a 1D tensor
self.labels = loaded_mat['y'].astype(np.int64).squeeze()
# the svhn dataset assigns the class label "10" to the digit 0
# this makes it inconsistent with several loss functions
# which expect the class labels to be in the range [0, C-1]
np.place(self.labels, self.labels == 10, 0)
self.data = np.transpose(self.data, (3, 2, 0, 1))
def __getitem__(self, index):
"""
Args:
index (int): Index
Returns:
tuple: (image, target) where target is index of the target class.
"""
img, target = self.data[index], int(self.labels[index])
# doing this so that it is consistent with all other datasets
# to return a PIL Image
img = Image.fromarray(np.transpose(img, (1, 2, 0)))
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
def __len__(self):
return len(self.data)
def _check_integrity(self):
root = self.root
md5 = self.split_list[self.split][2]
fpath = os.path.join(root, self.filename)
return check_integrity(fpath, md5)
def download(self):
md5 = self.split_list[self.split][2]
download_url(self.url, self.root, self.filename, md5)
def __repr__(self):
fmt_str = 'Dataset ' + self.__class__.__name__ + '\n'
fmt_str += ' Number of datapoints: {}\n'.format(self.__len__())
fmt_str += ' Split: {}\n'.format(self.split)
fmt_str += ' Root Location: {}\n'.format(self.root)
tmp = ' Transforms (if any): '
fmt_str += '{0}{1}\n'.format(tmp, self.transform.__repr__().replace('\n', '\n' + ' ' * len(tmp)))
tmp = ' Target Transforms (if any): '
fmt_str += '{0}{1}'.format(tmp, self.target_transform.__repr__().replace('\n', '\n' + ' ' * len(tmp)))
return fmt_str
