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from functools import partial
from typing import Any, Optional
import torch
import torch.nn as nn
from ..transforms._presets import ImageClassification
from ..utils import _log_api_usage_once
from ._api import register_model, Weights, WeightsEnum
from ._meta import _IMAGENET_CATEGORIES
from ._utils import _ovewrite_named_param, handle_legacy_interface
__all__ = ["AlexNet", "AlexNet_Weights", "alexnet"]
class AlexNet(nn.Module):
def __init__(self, num_classes: int = 1000, dropout: float = 0.5) -> None:
super().__init__()
_log_api_usage_once(self)
self.features = nn.Sequential(
nn.Conv2d(3, 64, kernel_size=11, stride=4, padding=2),
nn.ReLU(inplace=True),
nn.MaxPool2d(kernel_size=3, stride=2),
nn.Conv2d(64, 192, kernel_size=5, padding=2),
nn.ReLU(inplace=True),
nn.MaxPool2d(kernel_size=3, stride=2),
nn.Conv2d(192, 384, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(384, 256, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(256, 256, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.MaxPool2d(kernel_size=3, stride=2),
)
self.avgpool = nn.AdaptiveAvgPool2d((6, 6))
self.classifier = nn.Sequential(
nn.Dropout(p=dropout),
nn.Linear(256 * 6 * 6, 4096),
nn.ReLU(inplace=True),
nn.Dropout(p=dropout),
nn.Linear(4096, 4096),
nn.ReLU(inplace=True),
nn.Linear(4096, num_classes),
)
def forward(self, x: torch.Tensor) -> torch.Tensor:
x = self.features(x)
x = self.avgpool(x)
x = torch.flatten(x, 1)
x = self.classifier(x)
return x
class AlexNet_Weights(WeightsEnum):
IMAGENET1K_V1 = Weights(
url="https://download.pytorch.org/models/alexnet-owt-7be5be79.pth",
transforms=partial(ImageClassification, crop_size=224),
meta={
"num_params": 61100840,
"min_size": (63, 63),
"categories": _IMAGENET_CATEGORIES,
"recipe": "https://github.com/pytorch/vision/tree/main/references/classification#alexnet-and-vgg",
"_metrics": {
"ImageNet-1K": {
"acc@1": 56.522,
"acc@5": 79.066,
}
},
"_ops": 0.714,
"_file_size": 233.087,
"_docs": """
These weights reproduce closely the results of the paper using a simplified training recipe.
""",
},
)
DEFAULT = IMAGENET1K_V1
@register_model()
@handle_legacy_interface(weights=("pretrained", AlexNet_Weights.IMAGENET1K_V1))
def alexnet(*, weights: Optional[AlexNet_Weights] = None, progress: bool = True, **kwargs: Any) -> AlexNet:
"""AlexNet model architecture from `One weird trick for parallelizing convolutional neural networks <https://arxiv.org/abs/1404.5997>`__.
.. note::
AlexNet was originally introduced in the `ImageNet Classification with
Deep Convolutional Neural Networks
<https://papers.nips.cc/paper/2012/hash/c399862d3b9d6b76c8436e924a68c45b-Abstract.html>`__
paper. Our implementation is based instead on the "One weird trick"
paper above.
Args:
weights (:class:`~torchvision.models.AlexNet_Weights`, optional): The
pretrained weights to use. See
:class:`~torchvision.models.AlexNet_Weights` below for
more details, and possible values. By default, no pre-trained
weights are used.
progress (bool, optional): If True, displays a progress bar of the
download to stderr. Default is True.
**kwargs: parameters passed to the ``torchvision.models.squeezenet.AlexNet``
base class. Please refer to the `source code
<https://github.com/pytorch/vision/blob/main/torchvision/models/alexnet.py>`_
for more details about this class.
.. autoclass:: torchvision.models.AlexNet_Weights
:members:
"""
weights = AlexNet_Weights.verify(weights)
if weights is not None:
_ovewrite_named_param(kwargs, "num_classes", len(weights.meta["categories"]))
model = AlexNet(**kwargs)
if weights is not None:
model.load_state_dict(weights.get_state_dict(progress=progress, check_hash=True))
return model