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1.6.4 ... xcit

Author SHA1 Message Date
lucidrains
91211ecbef actually add xcit image 2023-10-13 09:15:31 -07:00
lucidrains
fb37832f66 document 2023-10-13 09:15:00 -07:00
lucidrains
d9679d3e26 give cross correlation transformer a final norm at end 2023-10-12 19:51:07 -07:00
lucidrains
bcfb0f054a use Rearrange layers 2023-10-12 19:48:31 -07:00
lucidrains
3dfb1579f7 add xcit 2023-10-12 19:32:50 -07:00
6 changed files with 13 additions and 169 deletions

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@@ -93,7 +93,7 @@ preds = v(img) # (1, 1000)
- `image_size`: int.
Image size. If you have rectangular images, make sure your image size is the maximum of the width and height
- `patch_size`: int.
Size of patches. `image_size` must be divisible by `patch_size`.
Number of patches. `image_size` must be divisible by `patch_size`.
The number of patches is: ` n = (image_size // patch_size) ** 2` and `n` **must be greater than 16**.
- `num_classes`: int.
Number of classes to classify.
@@ -777,7 +777,7 @@ pred = mbvit_xs(img) # (1, 1000)
<img src="./images/xcit.png" width="400px"></img>
This <a href="https://arxiv.org/abs/2106.09681">paper</a> introduces the cross covariance attention (abbreviated XCA). One can think of it as doing attention across the features dimension rather than the spatial one (another perspective would be a dynamic 1x1 convolution, the kernel being attention map defined by spatial correlations).
This <a href="https://arxiv.org/abs/2106.09681">paper</a> introduces the cross correlation attention (abbreviated XCA). One can think of it as doing attention across the features dimension rather than the spatial one (another perspective would be a dynamic 1x1 convolution, the kernel being attention map defined by spatial correlations).
Technically, this amounts to simply transposing the query, key, values before executing cosine similarity attention with learned temperature.

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@@ -3,7 +3,7 @@ from setuptools import setup, find_packages
setup(
name = 'vit-pytorch',
packages = find_packages(exclude=['examples']),
version = '1.6.4',
version = '1.6.0',
license='MIT',
description = 'Vision Transformer (ViT) - Pytorch',
long_description_content_type = 'text/markdown',

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@@ -1,3 +1,10 @@
import torch
from packaging import version
if version.parse(torch.__version__) >= version.parse('2.0.0'):
from einops._torch_specific import allow_ops_in_compiled_graph
allow_ops_in_compiled_graph()
from vit_pytorch.vit import ViT
from vit_pytorch.simple_vit import SimpleViT

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@@ -140,13 +140,12 @@ class CvT(nn.Module):
s3_heads = 6,
s3_depth = 10,
s3_mlp_mult = 4,
dropout = 0.,
channels = 3
dropout = 0.
):
super().__init__()
kwargs = dict(locals())
dim = channels
dim = 3
layers = []
for prefix in ('s1', 's2', 's3'):

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@@ -1,162 +0,0 @@
import torch
from torch.fft import fft
from torch import nn
from einops import rearrange, reduce, pack, unpack
from einops.layers.torch import Rearrange
# helpers
def pair(t):
return t if isinstance(t, tuple) else (t, t)
def posemb_sincos_2d(h, w, dim, temperature: int = 10000, dtype = torch.float32):
y, x = torch.meshgrid(torch.arange(h), torch.arange(w), indexing="ij")
assert (dim % 4) == 0, "feature dimension must be multiple of 4 for sincos emb"
omega = torch.arange(dim // 4) / (dim // 4 - 1)
omega = 1.0 / (temperature ** omega)
y = y.flatten()[:, None] * omega[None, :]
x = x.flatten()[:, None] * omega[None, :]
pe = torch.cat((x.sin(), x.cos(), y.sin(), y.cos()), dim=1)
return pe.type(dtype)
# classes
class FeedForward(nn.Module):
def __init__(self, dim, hidden_dim):
super().__init__()
self.net = nn.Sequential(
nn.LayerNorm(dim),
nn.Linear(dim, hidden_dim),
nn.GELU(),
nn.Linear(hidden_dim, dim),
)
def forward(self, x):
return self.net(x)
class Attention(nn.Module):
def __init__(self, dim, heads = 8, dim_head = 64):
super().__init__()
inner_dim = dim_head * heads
self.heads = heads
self.scale = dim_head ** -0.5
self.norm = nn.LayerNorm(dim)
self.attend = nn.Softmax(dim = -1)
self.to_qkv = nn.Linear(dim, inner_dim * 3, bias = False)
self.to_out = nn.Linear(inner_dim, dim, bias = False)
def forward(self, x):
x = self.norm(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.scale
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):
super().__init__()
self.norm = nn.LayerNorm(dim)
self.layers = nn.ModuleList([])
for _ in range(depth):
self.layers.append(nn.ModuleList([
Attention(dim, heads = heads, dim_head = dim_head),
FeedForward(dim, mlp_dim)
]))
def forward(self, x):
for attn, ff in self.layers:
x = attn(x) + x
x = ff(x) + x
return self.norm(x)
class SimpleViT(nn.Module):
def __init__(self, *, image_size, patch_size, freq_patch_size, num_classes, dim, depth, heads, mlp_dim, channels = 3, dim_head = 64):
super().__init__()
image_height, image_width = pair(image_size)
patch_height, patch_width = pair(patch_size)
freq_patch_height, freq_patch_width = pair(freq_patch_size)
assert image_height % patch_height == 0 and image_width % patch_width == 0, 'Image dimensions must be divisible by the patch size.'
assert image_height % freq_patch_height == 0 and image_width % freq_patch_width == 0, 'Image dimensions must be divisible by the freq patch size.'
patch_dim = channels * patch_height * patch_width
freq_patch_dim = channels * 2 * freq_patch_height * freq_patch_width
self.to_patch_embedding = nn.Sequential(
Rearrange("b c (h p1) (w p2) -> b (h w) (p1 p2 c)", p1 = patch_height, p2 = patch_width),
nn.LayerNorm(patch_dim),
nn.Linear(patch_dim, dim),
nn.LayerNorm(dim),
)
self.to_freq_embedding = nn.Sequential(
Rearrange("b c (h p1) (w p2) ri -> b (h w) (p1 p2 ri c)", p1 = freq_patch_height, p2 = freq_patch_width),
nn.LayerNorm(freq_patch_dim),
nn.Linear(freq_patch_dim, dim),
nn.LayerNorm(dim)
)
self.pos_embedding = posemb_sincos_2d(
h = image_height // patch_height,
w = image_width // patch_width,
dim = dim,
)
self.freq_pos_embedding = posemb_sincos_2d(
h = image_height // freq_patch_height,
w = image_width // freq_patch_width,
dim = dim
)
self.transformer = Transformer(dim, depth, heads, dim_head, mlp_dim)
self.pool = "mean"
self.to_latent = nn.Identity()
self.linear_head = nn.Linear(dim, num_classes)
def forward(self, img):
device, dtype = img.device, img.dtype
x = self.to_patch_embedding(img)
freqs = torch.view_as_real(fft(img))
f = self.to_freq_embedding(freqs)
x += self.pos_embedding.to(device, dtype = dtype)
f += self.freq_pos_embedding.to(device, dtype = dtype)
x, ps = pack((f, x), 'b * d')
x = self.transformer(x)
_, x = unpack(x, ps, 'b * d')
x = reduce(x, 'b n d -> b d', 'mean')
x = self.to_latent(x)
return self.linear_head(x)
if __name__ == '__main__':
vit = SimpleViT(
num_classes = 1000,
image_size = 256,
patch_size = 8,
freq_patch_size = 8,
dim = 1024,
depth = 1,
heads = 8,
mlp_dim = 2048,
)
images = torch.randn(8, 3, 256, 256)
logits = vit(images)

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@@ -10,7 +10,7 @@ class FeedForward(nn.Module):
def __init__(self, dim, hidden_dim, dropout = 0.):
super().__init__()
self.net = nn.Sequential(
nn.LayerNorm(dim),
nn.Layernorm(dim),
nn.Linear(dim, hidden_dim),
nn.GELU(),
nn.Dropout(dropout),