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import torch | |
import torch.nn as nn | |
import torch.nn.functional as F | |
from comfy.ldm.modules.attention import optimized_attention | |
import comfy.ops | |
class AttentionPool(nn.Module): | |
def __init__(self, spacial_dim: int, embed_dim: int, num_heads: int, output_dim: int = None, dtype=None, device=None, operations=None): | |
super().__init__() | |
self.positional_embedding = nn.Parameter(torch.empty(spacial_dim + 1, embed_dim, dtype=dtype, device=device)) | |
self.k_proj = operations.Linear(embed_dim, embed_dim, dtype=dtype, device=device) | |
self.q_proj = operations.Linear(embed_dim, embed_dim, dtype=dtype, device=device) | |
self.v_proj = operations.Linear(embed_dim, embed_dim, dtype=dtype, device=device) | |
self.c_proj = operations.Linear(embed_dim, output_dim or embed_dim, dtype=dtype, device=device) | |
self.num_heads = num_heads | |
self.embed_dim = embed_dim | |
def forward(self, x): | |
x = x[:,:self.positional_embedding.shape[0] - 1] | |
x = x.permute(1, 0, 2) # NLC -> LNC | |
x = torch.cat([x.mean(dim=0, keepdim=True), x], dim=0) # (L+1)NC | |
x = x + comfy.ops.cast_to_input(self.positional_embedding[:, None, :], x) # (L+1)NC | |
q = self.q_proj(x[:1]) | |
k = self.k_proj(x) | |
v = self.v_proj(x) | |
batch_size = q.shape[1] | |
head_dim = self.embed_dim // self.num_heads | |
q = q.view(1, batch_size * self.num_heads, head_dim).transpose(0, 1).view(batch_size, self.num_heads, -1, head_dim) | |
k = k.view(k.shape[0], batch_size * self.num_heads, head_dim).transpose(0, 1).view(batch_size, self.num_heads, -1, head_dim) | |
v = v.view(v.shape[0], batch_size * self.num_heads, head_dim).transpose(0, 1).view(batch_size, self.num_heads, -1, head_dim) | |
attn_output = optimized_attention(q, k, v, self.num_heads, skip_reshape=True).transpose(0, 1) | |
attn_output = self.c_proj(attn_output) | |
return attn_output.squeeze(0) | |