usps.py 文件源码

def __init__(self, root, train=True, transform=None, download=False):
        """Init USPS dataset."""
        # init params
        self.root = os.path.expanduser(root)
        self.filename = "usps_28x28.pkl"
        self.train = train
        # Num of Train = 7438, Num ot Test 1860
        self.transform = transform
        self.dataset_size = None

        # download dataset.
        if download:
            self.download()
        if not self._check_exists():
            raise RuntimeError("Dataset not found." +
                               " You can use download=True to download it")

        self.train_data, self.train_labels = self.load_samples()
        if self.train:
            total_num_samples = self.train_labels.shape[0]
            indices = np.arange(total_num_samples)
            np.random.shuffle(indices)
            self.train_data = self.train_data[indices[0:self.dataset_size], ::]
            self.train_labels = self.train_labels[indices[0:self.dataset_size]]
        self.train_data *= 255.0
        self.train_data = self.train_data.transpose(
            (0, 2, 3, 1))  # convert to HWC