Quantization Aware Training with NNCF, using PyTorch framework¶

%pip install -q "openvino>=2023.1.0" "torch" "torchvision"
%pip install -q "git+https://github.com/openvinotoolkit/nncf.git@release_v260"

# On Windows, add the directory that contains cl.exe to the PATH to enable PyTorch to find the
# required C++ tools. This code assumes that Visual Studio 2019 is installed in the default
# directory. If you have a different C++ compiler, add the correct path to os.environ["PATH"]
# directly. Note that the C++ Redistributable is not enough to run this notebook.

# Adding the path to os.environ["LIB"] is not always required - it depends on the system configuration

import sys

if sys.platform == "win32":
    import distutils.command.build_ext
    import os
    from pathlib import Path

    VS_INSTALL_DIR = r"C:/Program Files (x86)/Microsoft Visual Studio"
    cl_paths = sorted(list(Path(VS_INSTALL_DIR).glob("**/Hostx86/x64/cl.exe")))
    if len(cl_paths) == 0:
        raise ValueError(
            "Cannot find Visual Studio. This notebook requires a C++ compiler. If you installed "
            "a C++ compiler, please add the directory that contains cl.exe to `os.environ['PATH']`."
        )
    else:
        # If multiple versions of MSVC are installed, get the most recent one.
        cl_path = cl_paths[-1]
        vs_dir = str(cl_path.parent)
        os.environ["PATH"] += f"{os.pathsep}{vs_dir}"
        # The code for finding the library dirs is from:
        # https://stackoverflow.com/questions/47423246/get-pythons-lib-path
        d = distutils.core.Distribution()
        b = distutils.command.build_ext.build_ext(d)
        b.finalize_options()
        os.environ["LIB"] = os.pathsep.join(b.library_dirs)
        print(f"Added {vs_dir} to PATH")

def download_tiny_imagenet_200(
    data_dir: Path,
    url="http://cs231n.stanford.edu/tiny-imagenet-200.zip",
    tarname="tiny-imagenet-200.zip",
):
    archive_path = data_dir / tarname
    download_file(url, directory=data_dir, filename=tarname)
    zip_ref = zipfile.ZipFile(archive_path, "r")
    zip_ref.extractall(path=data_dir)
    zip_ref.close()

def prepare_tiny_imagenet_200(dataset_dir: Path):
    # Format validation set the same way as train set is formatted.
    val_data_dir = dataset_dir / 'val'
    val_annotations_file = val_data_dir / 'val_annotations.txt'
    with open(val_annotations_file, 'r') as f:
        val_annotation_data = map(lambda line: line.split('\t')[:2], f.readlines())
    val_images_dir = val_data_dir / 'images'
    for image_filename, image_label in val_annotation_data:
        from_image_filepath = val_images_dir / image_filename
        to_image_dir = val_data_dir / image_label
        if not to_image_dir.exists():
            to_image_dir.mkdir()
        to_image_filepath = to_image_dir / image_filename
        from_image_filepath.rename(to_image_filepath)
    val_annotations_file.unlink()
    val_images_dir.rmdir()
    

DATASET_DIR = DATA_DIR / "tiny-imagenet-200"
if not DATASET_DIR.exists():
    download_tiny_imagenet_200(DATA_DIR)
    prepare_tiny_imagenet_200(DATASET_DIR)
    print(f"Successfully downloaded and prepared dataset at: {DATASET_DIR}")

def train(train_loader, model, criterion, optimizer, epoch):
    batch_time = AverageMeter("Time", ":3.3f")
    losses = AverageMeter("Loss", ":2.3f")
    top1 = AverageMeter("Acc@1", ":2.2f")
    top5 = AverageMeter("Acc@5", ":2.2f")
    progress = ProgressMeter(
        len(train_loader), [batch_time, losses, top1, top5], prefix="Epoch:[{}]".format(epoch)
    )

    # Switch to train mode.
    model.train()

    end = time.time()
    for i, (images, target) in enumerate(train_loader):
        images = images.to(device)
        target = target.to(device)

        # Compute output.
        output = model(images)
        loss = criterion(output, target)

        # Measure accuracy and record loss.
        acc1, acc5 = accuracy(output, target, topk=(1, 5))
        losses.update(loss.item(), images.size(0))
        top1.update(acc1[0], images.size(0))
        top5.update(acc5[0], images.size(0))

        # Compute gradient and do opt step.
        optimizer.zero_grad()
        loss.backward()
        optimizer.step()

        # Measure elapsed time.
        batch_time.update(time.time() - end)
        end = time.time()

        print_frequency = 50
        if i % print_frequency == 0:
            progress.display(i)

def validate(val_loader, model, criterion):
    batch_time = AverageMeter("Time", ":3.3f")
    losses = AverageMeter("Loss", ":2.3f")
    top1 = AverageMeter("Acc@1", ":2.2f")
    top5 = AverageMeter("Acc@5", ":2.2f")
    progress = ProgressMeter(len(val_loader), [batch_time, losses, top1, top5], prefix="Test: ")

    # Switch to evaluate mode.
    model.eval()

    with torch.no_grad():
        end = time.time()
        for i, (images, target) in enumerate(val_loader):
            images = images.to(device)
            target = target.to(device)

            # Compute output.
            output = model(images)
            loss = criterion(output, target)

            # Measure accuracy and record loss.
            acc1, acc5 = accuracy(output, target, topk=(1, 5))
            losses.update(loss.item(), images.size(0))
            top1.update(acc1[0], images.size(0))
            top5.update(acc5[0], images.size(0))

            # Measure elapsed time.
            batch_time.update(time.time() - end)
            end = time.time()

            print_frequency = 10
            if i % print_frequency == 0:
                progress.display(i)

        print(" * Acc@1 {top1.avg:.3f} Acc@5 {top5.avg:.3f}".format(top1=top1, top5=top5))
    return top1.avg

class AverageMeter(object):
    """Computes and stores the average and current value"""

    def __init__(self, name, fmt=":f"):
        self.name = name
        self.fmt = fmt
        self.reset()

    def reset(self):
        self.val = 0
        self.avg = 0
        self.sum = 0
        self.count = 0

    def update(self, val, n=1):
        self.val = val
        self.sum += val * n
        self.count += n
        self.avg = self.sum / self.count

    def __str__(self):
        fmtstr = "{name} {val" + self.fmt + "} ({avg" + self.fmt + "})"
        return fmtstr.format(**self.__dict__)


class ProgressMeter(object):
    def __init__(self, num_batches, meters, prefix=""):
        self.batch_fmtstr = self._get_batch_fmtstr(num_batches)
        self.meters = meters
        self.prefix = prefix

    def display(self, batch):
        entries = [self.prefix + self.batch_fmtstr.format(batch)]
        entries += [str(meter) for meter in self.meters]
        print("\t".join(entries))

    def _get_batch_fmtstr(self, num_batches):
        num_digits = len(str(num_batches // 1))
        fmt = "{:" + str(num_digits) + "d}"
        return "[" + fmt + "/" + fmt.format(num_batches) + "]"


def accuracy(output, target, topk=(1,)):
    """Computes the accuracy over the k top predictions for the specified values of k"""
    with torch.no_grad():
        maxk = max(topk)
        batch_size = target.size(0)

        _, pred = output.topk(maxk, 1, True, True)
        pred = pred.t()
        correct = pred.eq(target.view(1, -1).expand_as(pred))

        res = []
        for k in topk:
            correct_k = correct[:k].reshape(-1).float().sum(0, keepdim=True)
            res.append(correct_k.mul_(100.0 / batch_size))
        return res

nncf_config_dict = {
    "input_info": {"sample_size": [1, 3, image_size, image_size]},
    "log_dir": str(OUTPUT_DIR),  # The log directory for NNCF-specific logging outputs.
    "compression": {
        "algorithm": "quantization",  # Specify the algorithm here.
    },
}
nncf_config = NNCFConfig.from_dict(nncf_config_dict)

nncf_config = register_default_init_args(nncf_config, train_loader)