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on
Zero
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import torch
from einops import rearrange
def low_version_attention(query, key, value, attn_bias=None):
scale = 1 / query.shape[-1] ** 0.5
query = query * scale
attn = torch.matmul(query, key.transpose(-2, -1))
if attn_bias is not None:
attn = attn + attn_bias
attn = attn.softmax(-1)
return attn @ value
class Attention(torch.nn.Module):
def __init__(self, q_dim, num_heads, head_dim, kv_dim=None, bias_q=False, bias_kv=False, bias_out=False):
super().__init__()
dim_inner = head_dim * num_heads
kv_dim = kv_dim if kv_dim is not None else q_dim
self.num_heads = num_heads
self.head_dim = head_dim
self.to_q = torch.nn.Linear(q_dim, dim_inner, bias=bias_q)
self.to_k = torch.nn.Linear(kv_dim, dim_inner, bias=bias_kv)
self.to_v = torch.nn.Linear(kv_dim, dim_inner, bias=bias_kv)
self.to_out = torch.nn.Linear(dim_inner, q_dim, bias=bias_out)
def interact_with_ipadapter(self, hidden_states, q, ip_k, ip_v, scale=1.0):
batch_size = q.shape[0]
ip_k = ip_k.view(batch_size, -1, self.num_heads, self.head_dim).transpose(1, 2)
ip_v = ip_v.view(batch_size, -1, self.num_heads, self.head_dim).transpose(1, 2)
ip_hidden_states = torch.nn.functional.scaled_dot_product_attention(q, ip_k, ip_v)
hidden_states = hidden_states + scale * ip_hidden_states
return hidden_states
def torch_forward(self, hidden_states, encoder_hidden_states=None, attn_mask=None, ipadapter_kwargs=None, qkv_preprocessor=None):
if encoder_hidden_states is None:
encoder_hidden_states = hidden_states
batch_size = encoder_hidden_states.shape[0]
q = self.to_q(hidden_states)
k = self.to_k(encoder_hidden_states)
v = self.to_v(encoder_hidden_states)
q = q.view(batch_size, -1, self.num_heads, self.head_dim).transpose(1, 2)
k = k.view(batch_size, -1, self.num_heads, self.head_dim).transpose(1, 2)
v = v.view(batch_size, -1, self.num_heads, self.head_dim).transpose(1, 2)
if qkv_preprocessor is not None:
q, k, v = qkv_preprocessor(q, k, v)
hidden_states = torch.nn.functional.scaled_dot_product_attention(q, k, v, attn_mask=attn_mask)
if ipadapter_kwargs is not None:
hidden_states = self.interact_with_ipadapter(hidden_states, q, **ipadapter_kwargs)
hidden_states = hidden_states.transpose(1, 2).reshape(batch_size, -1, self.num_heads * self.head_dim)
hidden_states = hidden_states.to(q.dtype)
hidden_states = self.to_out(hidden_states)
return hidden_states
def xformers_forward(self, hidden_states, encoder_hidden_states=None, attn_mask=None):
if encoder_hidden_states is None:
encoder_hidden_states = hidden_states
q = self.to_q(hidden_states)
k = self.to_k(encoder_hidden_states)
v = self.to_v(encoder_hidden_states)
q = rearrange(q, "b f (n d) -> (b n) f d", n=self.num_heads)
k = rearrange(k, "b f (n d) -> (b n) f d", n=self.num_heads)
v = rearrange(v, "b f (n d) -> (b n) f d", n=self.num_heads)
if attn_mask is not None:
hidden_states = low_version_attention(q, k, v, attn_bias=attn_mask)
else:
import xformers.ops as xops
hidden_states = xops.memory_efficient_attention(q, k, v)
hidden_states = rearrange(hidden_states, "(b n) f d -> b f (n d)", n=self.num_heads)
hidden_states = hidden_states.to(q.dtype)
hidden_states = self.to_out(hidden_states)
return hidden_states
def forward(self, hidden_states, encoder_hidden_states=None, attn_mask=None, ipadapter_kwargs=None, qkv_preprocessor=None):
return self.torch_forward(hidden_states, encoder_hidden_states=encoder_hidden_states, attn_mask=attn_mask, ipadapter_kwargs=ipadapter_kwargs, qkv_preprocessor=qkv_preprocessor) |