TorchVision_DataLoad

DataLoader(dataset, batch_size=1, shuffle=False, sampler=None,
           batch_sampler=None, num_workers=0, collate_fn=None,
           pin_memory=False, drop_last=False, timeout=0,
           worker_init_fn=None, *, prefetch_factor=2,
           persistent_workers=False)

class Dataset(Generic[T_co]):
    r"""An abstract class representing a :class:`Dataset`.

    All datasets that represent a map from keys to data samples should subclass
    it. All subclasses should overwrite :meth:`__getitem__`, supporting fetching a
    data sample for a given key. Subclasses could also optionally overwrite
    :meth:`__len__`, which is expected to return the size of the dataset by many
    :class:`~torch.utils.data.Sampler` implementations and the default options
    of :class:`~torch.utils.data.DataLoader`.

    .. note::
      :class:`~torch.utils.data.DataLoader` by default constructs a index
      sampler that yields integral indices.  To make it work with a map-style
      dataset with non-integral indices/keys, a custom sampler must be provided.
    """

    def __getitem__(self, index) -> T_co:
        raise NotImplementedError

    def __add__(self, other: 'Dataset[T_co]') -> 'ConcatDataset[T_co]':
        return ConcatDataset([self, other])


    # No `def __len__(self)` default?
    # See NOTE [ Lack of Default `__len__` in Python Abstract Base Classes ]
    # in pytorch/torch/utils/data/sampler.py

from .vision import VisionDataset
import warnings
from PIL import Image
import os
import os.path
import numpy as np
import torch
import codecs
import string
from .utils import download_url, download_and_extract_archive, extract_archive, \
    verify_str_arg
[docs]class MNIST(VisionDataset):
    """`MNIST <http://yann.lecun.com/exdb/mnist/>`_ Dataset.
    Args:
        root (string): Root directory of dataset where ``MNIST/processed/training.pt``
            and  ``MNIST/processed/test.pt`` exist.
        train (bool, optional): If True, creates dataset from ``training.pt``,
            otherwise from ``test.pt``.
        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.
        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.
    """
    resources = [
        ("http://yann.lecun.com/exdb/mnist/train-images-idx3-ubyte.gz", "f68b3c2dcbeaaa9fbdd348bbdeb94873"),
        ("http://yann.lecun.com/exdb/mnist/train-labels-idx1-ubyte.gz", "d53e105ee54ea40749a09fcbcd1e9432"),
        ("http://yann.lecun.com/exdb/mnist/t10k-images-idx3-ubyte.gz", "9fb629c4189551a2d022fa330f9573f3"),
        ("http://yann.lecun.com/exdb/mnist/t10k-labels-idx1-ubyte.gz", "ec29112dd5afa0611ce80d1b7f02629c")
    ]
    training_file = 'training.pt'
    test_file = 'test.pt'
    classes = ['0 - zero', '1 - one', '2 - two', '3 - three', '4 - four',
               '5 - five', '6 - six', '7 - seven', '8 - eight', '9 - nine']
    @property
    def train_labels(self):
        warnings.warn("train_labels has been renamed targets")
        return self.targets
    @property
    def test_labels(self):
        warnings.warn("test_labels has been renamed targets")
        return self.targets
    @property
    def train_data(self):
        warnings.warn("train_data has been renamed data")
        return self.data
    @property
    def test_data(self):
        warnings.warn("test_data has been renamed data")
        return self.data
    def __init__(self, root, train=True, transform=None, target_transform=None,
                 download=False):
        super(MNIST, self).__init__(root, transform=transform,
                                    target_transform=target_transform)
        self.train = train  # training set or test set
        if download:
            self.download()
        if not self._check_exists():
            raise RuntimeError('Dataset not found.' +
                               ' You can use download=True to download it')
        if self.train:
            data_file = self.training_file
        else:
            data_file = self.test_file
        self.data, self.targets = torch.load(os.path.join(self.processed_folder, data_file))
    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.targets[index])
        # doing this so that it is consistent with all other datasets
        # to return a PIL Image
        img = Image.fromarray(img.numpy(), mode='L')
        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)
    @property
    def raw_folder(self):
        return os.path.join(self.root, self.__class__.__name__, 'raw')
    @property
    def processed_folder(self):
        return os.path.join(self.root, self.__class__.__name__, 'processed')
    @property
    def class_to_idx(self):
        return {_class: i for i, _class in enumerate(self.classes)}
    def _check_exists(self):
        return (os.path.exists(os.path.join(self.processed_folder,
                                            self.training_file)) and
                os.path.exists(os.path.join(self.processed_folder,
                                            self.test_file)))
    def download(self):
        """Download the MNIST data if it doesn't exist in processed_folder already."""
        if self._check_exists():
            return
        os.makedirs(self.raw_folder, exist_ok=True)
        os.makedirs(self.processed_folder, exist_ok=True)
        # download files
        for url, md5 in self.resources:
            filename = url.rpartition('/')[2]
            download_and_extract_archive(url, download_root=self.raw_folder, filename=filename, md5=md5)
        # process and save as torch files
        print('Processing...')
        training_set = (
            read_image_file(os.path.join(self.raw_folder, 'train-images-idx3-ubyte')),
            read_label_file(os.path.join(self.raw_folder, 'train-labels-idx1-ubyte'))
        )
        test_set = (
            read_image_file(os.path.join(self.raw_folder, 't10k-images-idx3-ubyte')),
            read_label_file(os.path.join(self.raw_folder, 't10k-labels-idx1-ubyte'))
        )
        with open(os.path.join(self.processed_folder, self.training_file), 'wb') as f:
            torch.save(training_set, f)
        with open(os.path.join(self.processed_folder, self.test_file), 'wb') as f:
            torch.save(test_set, f)
        print('Done!')
    def extra_repr(self):
        return "Split: {}".format("Train" if self.train is True else "Test")

def load_data(root_path, dir, batch_size, phase):
    transform_dict = {
        'src': transforms.Compose(
        [transforms.RandomResizedCrop(224),
         transforms.RandomHorizontalFlip(),
         transforms.ToTensor(),
         transforms.Normalize(mean=[0.485, 0.456, 0.406],
                              std=[0.229, 0.224, 0.225]),
         ]),
        'tar': transforms.Compose(
        [transforms.Resize(224),
         transforms.ToTensor(),
         transforms.Normalize(mean=[0.485, 0.456, 0.406],
                              std=[0.229, 0.224, 0.225]),
         ])}
    data = datasets.ImageFolder(root=root_path + dir, transform=transform_dict[phase])
    data_loader = torch.utils.data.DataLoader(data, batch_size=batch_size, shuffle=True, drop_last=False, num_workers=4)
    return data_loader 

from multiprocessing import freeze_support
import torch
from torch import nn
from torch.autograd import Variable
from torch.utils.data import DataLoader, Sampler
from torchvision import datasets
from torchvision.transforms import transforms
from torch.optim import Adam
import matplotlib.pyplot as plt
import numpy as np
from pathlib import Path
# Hyperparameters.
num_epochs = 20
num_classes = 5
batch_size = 100
learning_rate = 0.001
num_of_workers = 5
DATA_PATH_TRAIN = Path('C:/Users/Aeryes/PycharmProjects/simplecnn/images/train/')
DATA_PATH_TEST = Path('C:/Users/Aeryes/PycharmProjects/simplecnn/images/test/')
MODEL_STORE_PATH = Path('C:/Users/Aeryes/PycharmProjects/simplecnn/model')
trans = transforms.Compose([
    transforms.RandomHorizontalFlip(),
    transforms.Resize(32),
    transforms.CenterCrop(32),
    transforms.ToTensor(),
    transforms.Normalize((0.5, 0.5, 0.5),(0.5, 0.5, 0.5))
    ])
# Flowers dataset.
train_dataset = datasets.ImageFolder(root=DATA_PATH_TRAIN, transform=trans)
test_dataset = datasets.ImageFolder(root=DATA_PATH_TEST, transform=trans)
# Create custom random sampler class to iter over dataloader.
train_loader = DataLoader(dataset=train_dataset, batch_size=batch_size, shuffle=True, num_workers=num_of_workers)
test_loader = DataLoader(dataset=test_dataset, batch_size=batch_size, shuffle=False, num_workers=num_of_workers)
for i, (images, labels) in enumerate(train_loader):   
    # Move images and labels to gpu if available
    if cuda_avail:
    images = Variable(images.cuda())
    labels = Variable(labels.cuda())