Spaces:
Running
on
L40S
Running
on
L40S
File size: 6,224 Bytes
4450790 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 |
import torch
from torch import einsum
import torch.nn.functional as F
import math
from einops import rearrange, repeat
from comfy.ldm.modules.attention import optimized_attention
import comfy.samplers
# from comfy/ldm/modules/attention.py
# but modified to return attention scores as well as output
def attention_basic_with_sim(q, k, v, heads, mask=None, attn_precision=None):
b, _, dim_head = q.shape
dim_head //= heads
scale = dim_head ** -0.5
h = heads
q, k, v = map(
lambda t: t.unsqueeze(3)
.reshape(b, -1, heads, dim_head)
.permute(0, 2, 1, 3)
.reshape(b * heads, -1, dim_head)
.contiguous(),
(q, k, v),
)
# force cast to fp32 to avoid overflowing
if attn_precision == torch.float32:
sim = einsum('b i d, b j d -> b i j', q.float(), k.float()) * scale
else:
sim = einsum('b i d, b j d -> b i j', q, k) * scale
del q, k
if mask is not None:
mask = rearrange(mask, 'b ... -> b (...)')
max_neg_value = -torch.finfo(sim.dtype).max
mask = repeat(mask, 'b j -> (b h) () j', h=h)
sim.masked_fill_(~mask, max_neg_value)
# attention, what we cannot get enough of
sim = sim.softmax(dim=-1)
out = einsum('b i j, b j d -> b i d', sim.to(v.dtype), v)
out = (
out.unsqueeze(0)
.reshape(b, heads, -1, dim_head)
.permute(0, 2, 1, 3)
.reshape(b, -1, heads * dim_head)
)
return (out, sim)
def create_blur_map(x0, attn, sigma=3.0, threshold=1.0):
# reshape and GAP the attention map
_, hw1, hw2 = attn.shape
b, _, lh, lw = x0.shape
attn = attn.reshape(b, -1, hw1, hw2)
# Global Average Pool
mask = attn.mean(1, keepdim=False).sum(1, keepdim=False) > threshold
total = mask.shape[-1]
x = round(math.sqrt((lh / lw) * total))
xx = None
for i in range(0, math.floor(math.sqrt(total) / 2)):
for j in [(x + i), max(1, x - i)]:
if total % j == 0:
xx = j
break
if xx is not None:
break
x = xx
y = total // x
# Reshape
mask = (
mask.reshape(b, x, y)
.unsqueeze(1)
.type(attn.dtype)
)
# Upsample
mask = F.interpolate(mask, (lh, lw))
blurred = gaussian_blur_2d(x0, kernel_size=9, sigma=sigma)
blurred = blurred * mask + x0 * (1 - mask)
return blurred
def gaussian_blur_2d(img, kernel_size, sigma):
ksize_half = (kernel_size - 1) * 0.5
x = torch.linspace(-ksize_half, ksize_half, steps=kernel_size)
pdf = torch.exp(-0.5 * (x / sigma).pow(2))
x_kernel = pdf / pdf.sum()
x_kernel = x_kernel.to(device=img.device, dtype=img.dtype)
kernel2d = torch.mm(x_kernel[:, None], x_kernel[None, :])
kernel2d = kernel2d.expand(img.shape[-3], 1, kernel2d.shape[0], kernel2d.shape[1])
padding = [kernel_size // 2, kernel_size // 2, kernel_size // 2, kernel_size // 2]
img = F.pad(img, padding, mode="reflect")
img = F.conv2d(img, kernel2d, groups=img.shape[-3])
return img
class SelfAttentionGuidance:
@classmethod
def INPUT_TYPES(s):
return {"required": { "model": ("MODEL",),
"scale": ("FLOAT", {"default": 0.5, "min": -2.0, "max": 5.0, "step": 0.01}),
"blur_sigma": ("FLOAT", {"default": 2.0, "min": 0.0, "max": 10.0, "step": 0.1}),
}}
RETURN_TYPES = ("MODEL",)
FUNCTION = "patch"
CATEGORY = "_for_testing"
def patch(self, model, scale, blur_sigma):
m = model.clone()
attn_scores = None
# TODO: make this work properly with chunked batches
# currently, we can only save the attn from one UNet call
def attn_and_record(q, k, v, extra_options):
nonlocal attn_scores
# if uncond, save the attention scores
heads = extra_options["n_heads"]
cond_or_uncond = extra_options["cond_or_uncond"]
b = q.shape[0] // len(cond_or_uncond)
if 1 in cond_or_uncond:
uncond_index = cond_or_uncond.index(1)
# do the entire attention operation, but save the attention scores to attn_scores
(out, sim) = attention_basic_with_sim(q, k, v, heads=heads, attn_precision=extra_options["attn_precision"])
# when using a higher batch size, I BELIEVE the result batch dimension is [uc1, ... ucn, c1, ... cn]
n_slices = heads * b
attn_scores = sim[n_slices * uncond_index:n_slices * (uncond_index+1)]
return out
else:
return optimized_attention(q, k, v, heads=heads, attn_precision=extra_options["attn_precision"])
def post_cfg_function(args):
nonlocal attn_scores
uncond_attn = attn_scores
sag_scale = scale
sag_sigma = blur_sigma
sag_threshold = 1.0
model = args["model"]
uncond_pred = args["uncond_denoised"]
uncond = args["uncond"]
cfg_result = args["denoised"]
sigma = args["sigma"]
model_options = args["model_options"]
x = args["input"]
if min(cfg_result.shape[2:]) <= 4: #skip when too small to add padding
return cfg_result
# create the adversarially blurred image
degraded = create_blur_map(uncond_pred, uncond_attn, sag_sigma, sag_threshold)
degraded_noised = degraded + x - uncond_pred
# call into the UNet
(sag,) = comfy.samplers.calc_cond_batch(model, [uncond], degraded_noised, sigma, model_options)
return cfg_result + (degraded - sag) * sag_scale
m.set_model_sampler_post_cfg_function(post_cfg_function, disable_cfg1_optimization=True)
# from diffusers:
# unet.mid_block.attentions[0].transformer_blocks[0].attn1.patch
m.set_model_attn1_replace(attn_and_record, "middle", 0, 0)
return (m, )
NODE_CLASS_MAPPINGS = {
"SelfAttentionGuidance": SelfAttentionGuidance,
}
NODE_DISPLAY_NAME_MAPPINGS = {
"SelfAttentionGuidance": "Self-Attention Guidance",
}
|