MaxVit model

docs/source/models.rst

@@ -207,6 +207,7 @@ weights:
    models/efficientnetv2
    models/googlenet
    models/inception
+   models/maxvit
    models/mnasnet
    models/mobilenetv2
    models/mobilenetv3

docs/source/models/maxvit.rst

@@ -0,0 +1,23 @@
+MaxVit
+===============
+
+.. currentmodule:: torchvision.models
+
+The MaxVit transformer models are based on the `MaxViT: Multi-Axis Vision Transformer <https://arxiv.org/abs/2204.01697>`__
+paper.
+
+
+Model builders
+--------------
+
+The following model builders can be used to instantiate an MaxVit model with and without pre-trained weights.
+All the model builders internally rely on the ``torchvision.models.maxvit.MaxVit`` 
+base class. Please refer to the `source code
+<https://github.com/pytorch/vision/blob/main/torchvision/models/maxvit.py>`_ for
+more details about this class.
+
+.. autosummary::
+    :toctree: generated/
+    :template: function.rst
+
+    maxvit_t

references/classification/README.md

@@ -245,6 +245,14 @@ Here `$MODEL` is one of `swin_v2_t`, `swin_v2_s` or `swin_v2_b`.
 Note that `--val-resize-size` was optimized in a post-training step, see their `Weights` entry for the exact value.
 
 
+### MaxViT
+```
+torchrun --nproc_per_node=8 --n_nodes=4 train.py\
+--model $MODEL --epochs 400 --batch-size 128 --opt adamw --lr 3e-3 --weight-decay 0.05 --lr-scheduler cosineannealinglr --lr-min 1e-5 --lr-warmup-method linear  --lr-warmup-epochs 32  --label-smoothing 0.1 --mixup-alpha 0.8 --clip-grad-norm 1.0 --interpolation bicubic --auto-augment ta_wide --policy-magnitude 15  --train-center-crop --model-ema --val-resize-size 224
+--val-crop-size 224 --train-crop-size 224 --amp  --model-ema-steps 32 --transformer-embedding-decay 0 --sync-bn
+```
+Here `$MODEL` is `maxvit_t`.
+Note that `--val-resize-size` was not optimized in a post-training step.
 
 
 ### ShuffleNet V2

references/classification/presets.py

@@ -13,18 +13,25 @@ def __init__(
         interpolation=InterpolationMode.BILINEAR,
         hflip_prob=0.5,
         auto_augment_policy=None,
+        ra_magnitude=9,
+        augmix_severity=3,
         random_erase_prob=0.0,
+        center_crop=False,
     ):
-        trans = [transforms.RandomResizedCrop(crop_size, interpolation=interpolation)]
+        trans = (
+            [transforms.RandomResizedCrop(crop_size, interpolation=interpolation)]
+            if center_crop
+            else [transforms.CenterCrop(crop_size)]
+        )
         if hflip_prob > 0:
             trans.append(transforms.RandomHorizontalFlip(hflip_prob))
         if auto_augment_policy is not None:
             if auto_augment_policy == "ra":
-                trans.append(autoaugment.RandAugment(interpolation=interpolation))
+                trans.append(autoaugment.RandAugment(interpolation=interpolation, magnitude=ra_magnitude))
             elif auto_augment_policy == "ta_wide":
                 trans.append(autoaugment.TrivialAugmentWide(interpolation=interpolation))
             elif auto_augment_policy == "augmix":
-                trans.append(autoaugment.AugMix(interpolation=interpolation))
+                trans.append(autoaugment.AugMix(interpolation=interpolation, severity=augmix_severity))
             else:
                 aa_policy = autoaugment.AutoAugmentPolicy(auto_augment_policy)
                 trans.append(autoaugment.AutoAugment(policy=aa_policy, interpolation=interpolation))

references/classification/train.py

@@ -113,7 +113,12 @@ def _get_cache_path(filepath):
 def load_data(traindir, valdir, args):
     # Data loading code
     print("Loading data")
-    val_resize_size, val_crop_size, train_crop_size = args.val_resize_size, args.val_crop_size, args.train_crop_size
+    val_resize_size, val_crop_size, train_crop_size, center_crop = (
+        args.val_resize_size,
+        args.val_crop_size,
+        args.train_crop_size,
+        args.train_center_crop,
+    )
     interpolation = InterpolationMode(args.interpolation)
 
     print("Loading training data")
@@ -126,13 +131,18 @@ def load_data(traindir, valdir, args):
     else:
         auto_augment_policy = getattr(args, "auto_augment", None)
         random_erase_prob = getattr(args, "random_erase", 0.0)
+        ra_magnitude = args.ra_magnitude
+        augmix_severity = args.augmix_severity
         dataset = torchvision.datasets.ImageFolder(
             traindir,
             presets.ClassificationPresetTrain(
+                center_crop=center_crop,
                 crop_size=train_crop_size,
                 interpolation=interpolation,
                 auto_augment_policy=auto_augment_policy,
                 random_erase_prob=random_erase_prob,
+                ra_magnitude=ra_magnitude,
+                augmix_severity=augmix_severity,
             ),
         )
         if args.cache_dataset:
@@ -207,7 +217,10 @@ def main(args):
         mixup_transforms.append(transforms.RandomCutmix(num_classes, p=1.0, alpha=args.cutmix_alpha))
     if mixup_transforms:
         mixupcutmix = torchvision.transforms.RandomChoice(mixup_transforms)
-        collate_fn = lambda batch: mixupcutmix(*default_collate(batch))  # noqa: E731
+
+        def collate_fn(batch):
+            return mixupcutmix(*default_collate(batch))
+
     data_loader = torch.utils.data.DataLoader(
         dataset,
         batch_size=args.batch_size,
@@ -448,6 +461,8 @@ def get_args_parser(add_help=True):
         action="store_true",
     )
     parser.add_argument("--auto-augment", default=None, type=str, help="auto augment policy (default: None)")
+    parser.add_argument("--ra-magnitude", default=9, type=int, help="magnitude of auto augment policy")
+    parser.add_argument("--augmix-severity", default=3, type=int, help="severity of augmix policy")
     parser.add_argument("--random-erase", default=0.0, type=float, help="random erasing probability (default: 0.0)")
 
     # Mixed precision training parameters
@@ -486,13 +501,17 @@ def get_args_parser(add_help=True):
     parser.add_argument(
         "--train-crop-size", default=224, type=int, help="the random crop size used for training (default: 224)"
     )
+    parser.add_argument(
+        "--train-center-crop",
+        action="store_true",
+        help="use center crop instead of random crop for training (default: False)",
+    )
     parser.add_argument("--clip-grad-norm", default=None, type=float, help="the maximum gradient norm (default None)")
     parser.add_argument("--ra-sampler", action="store_true", help="whether to use Repeated Augmentation in training")
     parser.add_argument(
         "--ra-reps", default=3, type=int, help="number of repetitions for Repeated Augmentation (default: 3)"
     )
     parser.add_argument("--weights", default=None, type=str, help="the weights enum name to load")
-
     return parser
 
 

test/test_architecture_ops.py

@@ -0,0 +1,46 @@
+import unittest
+
+import pytest
+import torch
+
+from torchvision.models.maxvit import SwapAxes, WindowDepartition, WindowPartition
+
+
+class MaxvitTester(unittest.TestCase):
+    def test_maxvit_window_partition(self):
+        input_shape = (1, 3, 224, 224)
+        partition_size = 7
+        n_partitions = input_shape[3] // partition_size
+
+        x = torch.randn(input_shape)
+
+        partition = WindowPartition()
+        departition = WindowDepartition()
+
+        x_hat = partition(x, partition_size)
+        x_hat = departition(x_hat, partition_size, n_partitions, n_partitions)
+
+        assert torch.allclose(x, x_hat)
+
+    def test_maxvit_grid_partition(self):
+        input_shape = (1, 3, 224, 224)
+        partition_size = 7
+        n_partitions = input_shape[3] // partition_size
+
+        x = torch.randn(input_shape)
+        pre_swap = SwapAxes(-2, -3)
+        post_swap = SwapAxes(-2, -3)
+
+        partition = WindowPartition()
+        departition = WindowDepartition()
+
+        x_hat = partition(x, n_partitions)
+        x_hat = pre_swap(x_hat)
+        x_hat = post_swap(x_hat)
+        x_hat = departition(x_hat, n_partitions, partition_size, partition_size)
+
+        assert torch.allclose(x, x_hat)
+
+
+if __name__ == "__main__":
+    pytest.main([__file__])

torchvision/models/__init__.py

@@ -13,5 +13,6 @@
 from .vgg import *
 from .vision_transformer import *
 from .swin_transformer import *
+from .maxvit import *
 from . import detection, optical_flow, quantization, segmentation, video
 from ._api import get_model, get_model_builder, get_model_weights, get_weight, list_models