diff --git a/README.md b/README.md
index 87de09d..d98f999 100644
--- a/README.md
+++ b/README.md
@@ -24,6 +24,7 @@
- [Simple Masked Image Modeling](#simple-masked-image-modeling)
- [Masked Patch Prediction](#masked-patch-prediction)
- [Adaptive Token Sampling](#adaptive-token-sampling)
+- [Vision Transformer for Small Datasets](#vision-transformer-for-small-datasets)
- [Dino](#dino)
- [Accessing Attention](#accessing-attention)
- [Research Ideas](#research-ideas)
@@ -739,6 +740,52 @@ preds = v(img) # (1, 1000)
preds, token_ids = v(img, return_sampled_token_ids = True) # (1, 1000), (1, <=8)
```
+## Vision Transformer for Small Datasets
+
+
+
+This paper proposes a new image to patch function that incorporates shifts of the image, before normalizing and dividing the image into patches. I have found shifting to be extremely helpful in some other transformers work, so decided to include this for further explorations. It also includes the `LRA` with the learned temperature and masking out of token attention to itself.
+
+You can use as follows:
+
+```python
+import torch
+from vit_pytorch.vit_for_small_dataset import ViT
+
+v = ViT(
+ image_size = 256,
+ patch_size = 16,
+ num_classes = 1000,
+ dim = 1024,
+ depth = 6,
+ heads = 16,
+ mlp_dim = 2048,
+ dropout = 0.1,
+ emb_dropout = 0.1
+)
+
+img = torch.randn(4, 3, 256, 256)
+
+preds = v(img) # (1, 1000)
+```
+
+You can also use the `SPT` from this paper as a standalone module
+
+```python
+import torch
+from vit_pytorch.vit_for_small_dataset import SPT
+
+spt = SPT(
+ dim = 1024,
+ patch_size = 16,
+ channels = 3
+)
+
+img = torch.randn(4, 3, 256, 256)
+
+tokens = spt(img) # (4, 256, 1024)
+```
+
## Dino
@@ -1236,6 +1283,17 @@ Coming from computer vision and new to transformers? Here are some resources tha
}
```
+```bibtex
+@misc{lee2021vision,
+ title = {Vision Transformer for Small-Size Datasets},
+ author = {Seung Hoon Lee and Seunghyun Lee and Byung Cheol Song},
+ year = {2021},
+ eprint = {2112.13492},
+ archivePrefix = {arXiv},
+ primaryClass = {cs.CV}
+}
+```
+
```bibtex
@misc{vaswani2017attention,
title = {Attention Is All You Need},
diff --git a/images/vit_for_small_datasets.png b/images/vit_for_small_datasets.png
new file mode 100644
index 0000000..c52b83d
Binary files /dev/null and b/images/vit_for_small_datasets.png differ
diff --git a/setup.py b/setup.py
index ae59572..d9583ae 100644
--- a/setup.py
+++ b/setup.py
@@ -3,7 +3,7 @@ from setuptools import setup, find_packages
setup(
name = 'vit-pytorch',
packages = find_packages(exclude=['examples']),
- version = '0.25.6',
+ version = '0.26.0',
license='MIT',
description = 'Vision Transformer (ViT) - Pytorch',
author = 'Phil Wang',
diff --git a/vit_pytorch/extractor.py b/vit_pytorch/extractor.py
index 54fc05e..297c577 100644
--- a/vit_pytorch/extractor.py
+++ b/vit_pytorch/extractor.py
@@ -10,6 +10,7 @@ class Extractor(nn.Module):
vit,
device = None,
layer_name = 'transformer',
+ layer_save_input = False,
return_embeddings_only = False
):
super().__init__()
@@ -23,10 +24,12 @@ class Extractor(nn.Module):
self.device = device
self.layer_name = layer_name
+ self.layer_save_input = layer_save_input # whether to save input or output of layer
self.return_embeddings_only = return_embeddings_only
- def _hook(self, _, input, output):
- self.latents = output.clone().detach()
+ def _hook(self, _, inputs, output):
+ tensor_to_save = inputs if self.layer_save_input else output
+ self.latents = tensor_to_save.clone().detach()
def _register_hook(self):
assert hasattr(self.vit, self.layer_name), 'layer whose output to take as embedding not found in vision transformer'
diff --git a/vit_pytorch/vit_for_small_dataset.py b/vit_pytorch/vit_for_small_dataset.py
new file mode 100644
index 0000000..0e223ce
--- /dev/null
+++ b/vit_pytorch/vit_for_small_dataset.py
@@ -0,0 +1,142 @@
+from math import sqrt
+import torch
+import torch.nn.functional as F
+from torch import nn
+
+from einops import rearrange, repeat
+from einops.layers.torch import Rearrange
+
+# helpers
+
+def pair(t):
+ return t if isinstance(t, tuple) else (t, t)
+
+# classes
+
+class PreNorm(nn.Module):
+ def __init__(self, dim, fn):
+ super().__init__()
+ self.norm = nn.LayerNorm(dim)
+ self.fn = fn
+ def forward(self, x, **kwargs):
+ return self.fn(self.norm(x), **kwargs)
+
+class FeedForward(nn.Module):
+ def __init__(self, dim, hidden_dim, dropout = 0.):
+ super().__init__()
+ self.net = nn.Sequential(
+ nn.Linear(dim, hidden_dim),
+ nn.GELU(),
+ nn.Dropout(dropout),
+ nn.Linear(hidden_dim, dim),
+ nn.Dropout(dropout)
+ )
+ def forward(self, x):
+ return self.net(x)
+
+class LSA(nn.Module):
+ def __init__(self, dim, heads = 8, dim_head = 64, dropout = 0.):
+ super().__init__()
+ inner_dim = dim_head * heads
+ self.heads = heads
+ self.temperature = nn.Parameter(torch.log(torch.tensor(dim_head ** -0.5)))
+
+ self.attend = nn.Softmax(dim = -1)
+ self.to_qkv = nn.Linear(dim, inner_dim * 3, bias = False)
+
+ self.to_out = nn.Sequential(
+ nn.Linear(inner_dim, dim),
+ nn.Dropout(dropout)
+ )
+
+ def forward(self, x):
+ qkv = self.to_qkv(x).chunk(3, dim = -1)
+ q, k, v = map(lambda t: rearrange(t, 'b n (h d) -> b h n d', h = self.heads), qkv)
+
+ dots = torch.matmul(q, k.transpose(-1, -2)) * self.temperature.exp()
+
+ mask = torch.eye(dots.shape[-1], device = dots.device, dtype = torch.bool)
+ mask_value = -torch.finfo(dots.dtype).max
+ dots = dots.masked_fill(mask, mask_value)
+
+ attn = self.attend(dots)
+
+ out = torch.matmul(attn, v)
+ out = rearrange(out, 'b h n d -> b n (h d)')
+ return self.to_out(out)
+
+class Transformer(nn.Module):
+ def __init__(self, dim, depth, heads, dim_head, mlp_dim, dropout = 0.):
+ super().__init__()
+ self.layers = nn.ModuleList([])
+ for _ in range(depth):
+ self.layers.append(nn.ModuleList([
+ PreNorm(dim, LSA(dim, heads = heads, dim_head = dim_head, dropout = dropout)),
+ PreNorm(dim, FeedForward(dim, mlp_dim, dropout = dropout))
+ ]))
+ def forward(self, x):
+ for attn, ff in self.layers:
+ x = attn(x) + x
+ x = ff(x) + x
+ return x
+
+class SPT(nn.Module):
+ def __init__(self, *, dim, patch_size, channels = 3):
+ super().__init__()
+ patch_dim = patch_size * patch_size * 5 * channels
+
+ self.to_patch_tokens = nn.Sequential(
+ Rearrange('b c (h p1) (w p2) -> b (h w) (p1 p2 c)', p1 = patch_size, p2 = patch_size),
+ nn.LayerNorm(patch_dim),
+ nn.Linear(patch_dim, dim)
+ )
+
+ def forward(self, x):
+ shifts = ((1, -1, 0, 0), (-1, 1, 0, 0), (0, 0, 1, -1), (0, 0, -1, 1))
+ shifted_x = list(map(lambda shift: F.pad(x, shift), shifts))
+ x_with_shifts = torch.cat((x, *shifted_x), dim = 1)
+ return self.to_patch_tokens(x_with_shifts)
+
+class ViT(nn.Module):
+ def __init__(self, *, image_size, patch_size, num_classes, dim, depth, heads, mlp_dim, pool = 'cls', channels = 3, dim_head = 64, dropout = 0., emb_dropout = 0.):
+ super().__init__()
+ image_height, image_width = pair(image_size)
+ patch_height, patch_width = pair(patch_size)
+
+ assert image_height % patch_height == 0 and image_width % patch_width == 0, 'Image dimensions must be divisible by the patch size.'
+
+ num_patches = (image_height // patch_height) * (image_width // patch_width)
+ patch_dim = channels * patch_height * patch_width
+ assert pool in {'cls', 'mean'}, 'pool type must be either cls (cls token) or mean (mean pooling)'
+
+ self.to_patch_embedding = SPT(dim = dim, patch_size = patch_size, channels = channels)
+
+ self.pos_embedding = nn.Parameter(torch.randn(1, num_patches + 1, dim))
+ self.cls_token = nn.Parameter(torch.randn(1, 1, dim))
+ self.dropout = nn.Dropout(emb_dropout)
+
+ self.transformer = Transformer(dim, depth, heads, dim_head, mlp_dim, dropout)
+
+ self.pool = pool
+ self.to_latent = nn.Identity()
+
+ self.mlp_head = nn.Sequential(
+ nn.LayerNorm(dim),
+ nn.Linear(dim, num_classes)
+ )
+
+ def forward(self, img):
+ x = self.to_patch_embedding(img)
+ b, n, _ = x.shape
+
+ cls_tokens = repeat(self.cls_token, '() n d -> b n d', b = b)
+ x = torch.cat((cls_tokens, x), dim=1)
+ x += self.pos_embedding[:, :(n + 1)]
+ x = self.dropout(x)
+
+ x = self.transformer(x)
+
+ x = x.mean(dim = 1) if self.pool == 'mean' else x[:, 0]
+
+ x = self.to_latent(x)
+ return self.mlp_head(x)