imaginAIry/imaginairy/modules/attention.py
2023-02-15 14:22:00 -08:00

496 lines
16 KiB
Python

import math
from functools import lru_cache
import psutil
import torch
import torch.nn.functional as F
from einops import rearrange
from torch import einsum, nn
from imaginairy.modules.diffusion.util import checkpoint as checkpoint_eval
from imaginairy.utils import get_device
XFORMERS_IS_AVAILABLE = False
try:
if get_device() == "cuda":
import xformers # noqa
import xformers.ops # noqa
XFORMERS_IS_AVAILABLE = True
except ImportError:
pass
ALLOW_SPLITMEM = True
ATTENTION_PRECISION_OVERRIDE = "default"
class GEGLU(nn.Module):
def __init__(self, dim_in, dim_out):
super().__init__()
self.proj = nn.Linear(dim_in, dim_out * 2)
def forward(self, x):
x, gate = self.proj(x).chunk(2, dim=-1)
return x * F.gelu(gate)
class FeedForward(nn.Module):
def __init__(self, dim, dim_out=None, mult=4, glu=False, dropout=0.0):
super().__init__()
inner_dim = int(dim * mult)
dim_out = dim_out if dim_out is not None else dim
project_in = (
nn.Sequential(nn.Linear(dim, inner_dim), nn.GELU())
if not glu
else GEGLU(dim, inner_dim)
)
self.net = nn.Sequential(
project_in, nn.Dropout(dropout), nn.Linear(inner_dim, dim_out)
)
def forward(self, x):
return self.net(x)
def zero_module(module):
"""
Zero out the parameters of a module and return it.
"""
for p in module.parameters():
p.detach().zero_()
return module
def Normalize(in_channels):
return torch.nn.GroupNorm(
num_groups=32, num_channels=in_channels, eps=1e-6, affine=True
)
class LinearAttention(nn.Module):
def __init__(self, dim, heads=4, dim_head=32):
super().__init__()
self.heads = heads
hidden_dim = dim_head * heads
self.to_qkv = nn.Conv2d(dim, hidden_dim * 3, 1, bias=False)
self.to_out = nn.Conv2d(hidden_dim, dim, 1)
def forward(self, x):
b, c, h, w = x.shape # noqa
qkv = self.to_qkv(x)
q, k, v = rearrange(
qkv, "b (qkv heads c) h w -> qkv b heads c (h w)", heads=self.heads, qkv=3
)
k = k.softmax(dim=-1)
context = torch.einsum("bhdn,bhen->bhde", k, v)
out = torch.einsum("bhde,bhdn->bhen", context, q)
out = rearrange(
out, "b heads c (h w) -> b (heads c) h w", heads=self.heads, h=h, w=w
)
return self.to_out(out)
class SpatialSelfAttention(nn.Module):
def __init__(self, in_channels):
super().__init__()
self.in_channels = in_channels
self.norm = Normalize(in_channels)
self.q = torch.nn.Conv2d(
in_channels, in_channels, kernel_size=1, stride=1, padding=0
)
self.k = torch.nn.Conv2d(
in_channels, in_channels, kernel_size=1, stride=1, padding=0
)
self.v = torch.nn.Conv2d(
in_channels, in_channels, kernel_size=1, stride=1, padding=0
)
self.proj_out = torch.nn.Conv2d(
in_channels, in_channels, kernel_size=1, stride=1, padding=0
)
def forward(self, x):
h_ = x
h_ = self.norm(h_)
q = self.q(h_)
k = self.k(h_)
v = self.v(h_)
# compute attention
b, c, h, w = q.shape # noqa
q = rearrange(q, "b c h w -> b (h w) c")
k = rearrange(k, "b c h w -> b c (h w)")
w_ = torch.einsum("bij,bjk->bik", q, k)
w_ = w_ * (int(c) ** (-0.5))
w_ = torch.nn.functional.softmax(w_, dim=2)
# attend to values
v = rearrange(v, "b c h w -> b c (h w)")
w_ = rearrange(w_, "b i j -> b j i")
h_ = torch.einsum("bij,bjk->bik", v, w_)
h_ = rearrange(h_, "b c (h w) -> b c h w", h=h)
h_ = self.proj_out(h_)
return x + h_
def get_mem_free_total(device):
device_type = "mps" if device.type == "mps" else "cuda"
if device_type == "cuda":
stats = torch.cuda.memory_stats(device)
mem_active = stats["active_bytes.all.current"]
mem_reserved = stats["reserved_bytes.all.current"]
mem_free_cuda, _ = torch.cuda.mem_get_info(torch.cuda.current_device())
mem_free_torch = mem_reserved - mem_active
mem_free_total = mem_free_cuda + mem_free_torch
mem_free_total *= 0.9
else:
# if we don't add a buffer, larger images come out as noise
mem_free_total = psutil.virtual_memory().available * 0.6
return mem_free_total
@lru_cache(maxsize=1)
def get_mps_gb_ram():
return psutil.virtual_memory().total / (1024**3)
class CrossAttention(nn.Module):
def __init__(self, query_dim, context_dim=None, heads=8, dim_head=64, dropout=0.0):
super().__init__()
inner_dim = dim_head * heads
context_dim = context_dim if context_dim is not None else query_dim
self.scale = dim_head**-0.5
self.heads = heads
self.to_q = nn.Linear(query_dim, inner_dim, bias=False)
self.to_k = nn.Linear(context_dim, inner_dim, bias=False)
self.to_v = nn.Linear(context_dim, inner_dim, bias=False)
self.to_out = nn.Sequential(
nn.Linear(inner_dim, query_dim), nn.Dropout(dropout)
)
def forward(self, x, context=None, mask=None):
# from imaginairy.api import _global_mask_hack
#
# if mask is None and _global_mask_hack is not None:
# mask = _global_mask_hack.to(torch.bool)
if get_device() == "cuda" or "mps" in get_device():
if not XFORMERS_IS_AVAILABLE and ALLOW_SPLITMEM:
return self.forward_splitmem(x, context=context, mask=mask)
h = self.heads
# print(x.shape)
q = self.to_q(x)
context = context if context is not None else x
k = self.to_k(context) * self.scale
v = self.to_v(context)
q, k, v = (rearrange(t, "b n (h d) -> (b h) n d", h=h) for t in (q, k, v))
# force cast to fp32 to avoid overflowing
if ATTENTION_PRECISION_OVERRIDE == "fp32":
with torch.autocast(enabled=False, device_type=get_device()):
q, k = q.float(), k.float()
sim = einsum("b i d, b j d -> b i j", q, k)
else:
sim = einsum("b i d, b j d -> b i j", q, k)
# print(sim.shape)
# print("*" * 100)
del q, k
# if mask is not None:
# if sim.shape[2] == 320 and False:
# mask = [mask] * 2
# 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
attn = sim.softmax(dim=-1)
out = einsum("b i j, b j d -> b i d", attn, v)
out = rearrange(out, "(b h) n d -> b n (h d)", h=h)
return self.to_out(out)
def forward_splitmem(self, x, context=None, mask=None): # noqa
h = self.heads
q_in = self.to_q(x)
context = context if context is not None else x
k_in = self.to_k(context) * self.scale
v_in = self.to_v(context)
del context, x
q, k, v = (
rearrange(t, "b n (h d) -> (b h) n d", h=h) for t in (q_in, k_in, v_in)
)
del q_in, k_in, v_in
r1 = torch.zeros(q.shape[0], q.shape[1], v.shape[2], device=q.device)
mem_free_total = get_mem_free_total(q.device)
gb = 1024**3
tensor_size = q.shape[0] * q.shape[1] * k.shape[1] * q.element_size()
modifier = 3 if q.element_size() == 2 else 2.5
mem_required = tensor_size * modifier
steps = 1
if "mps" in get_device():
# https://github.com/brycedrennan/imaginAIry/issues/175
# https://github.com/invoke-ai/InvokeAI/issues/1244
mps_gb = get_mps_gb_ram()
factor = 32 / mps_gb
slice_size = math.floor(2**30 / (q.shape[0] * q.shape[1] * 16 * factor))
else:
if mem_required > mem_free_total:
steps = 2 ** (math.ceil(math.log(mem_required / mem_free_total, 2)))
if steps > 64:
max_res = (
math.floor(math.sqrt(math.sqrt(mem_free_total / 2.5)) / 8) * 64
)
raise RuntimeError(
f"Not enough memory, use lower resolution (max approx. {max_res}x{max_res}). "
f"Need: {mem_required / 64 / gb:0.1f}GB free, Have:{mem_free_total / gb:0.1f}GB free"
)
slice_size = (
q.shape[1] // steps if (q.shape[1] % steps) == 0 else q.shape[1]
)
# steps = len(range(0, q.shape[1], slice_size))
# print(f"Splitting attention into {steps} steps of {slice_size} slices")
for i in range(0, q.shape[1], slice_size):
end = i + slice_size
# force cast to fp32 to avoid overflowing
if ATTENTION_PRECISION_OVERRIDE == "fp32":
with torch.autocast(enabled=False, device_type=get_device()):
q, k = q.float(), k.float()
s1 = einsum("b i d, b j d -> b i j", q[:, i:end], k)
else:
s1 = einsum("b i d, b j d -> b i j", q[:, i:end], k)
s2 = s1.softmax(dim=-1, dtype=q.dtype)
del s1
r1[:, i:end] = einsum("b i j, b j d -> b i d", s2, v)
del s2
del q, k, v
r2 = rearrange(r1, "(b h) n d -> b n (h d)", h=h)
del r1
return self.to_out(r2)
class MemoryEfficientCrossAttention(nn.Module):
# https://github.com/MatthieuTPHR/diffusers/blob/d80b531ff8060ec1ea982b65a1b8df70f73aa67c/src/diffusers/models/attention.py#L223
def __init__(self, query_dim, context_dim=None, heads=8, dim_head=64, dropout=0.0):
super().__init__()
# print(
# f"Setting up {self.__class__.__name__}. Query dim is {query_dim}, context_dim is {context_dim} and using "
# f"{heads} heads."
# )
inner_dim = dim_head * heads
context_dim = context_dim if context_dim is not None else query_dim
self.heads = heads
self.dim_head = dim_head
self.to_q = nn.Linear(query_dim, inner_dim, bias=False)
self.to_k = nn.Linear(context_dim, inner_dim, bias=False)
self.to_v = nn.Linear(context_dim, inner_dim, bias=False)
self.to_out = nn.Sequential(
nn.Linear(inner_dim, query_dim), nn.Dropout(dropout)
)
self.attention_op = None
def forward(self, x, context=None, mask=None):
q = self.to_q(x)
context = context if context is not None else x
k = self.to_k(context)
v = self.to_v(context)
b, _, _ = q.shape
q, k, v = (
t.unsqueeze(3)
.reshape(b, t.shape[1], self.heads, self.dim_head)
.permute(0, 2, 1, 3)
.reshape(b * self.heads, t.shape[1], self.dim_head)
.contiguous()
for t in (q, k, v)
)
# actually compute the attention, what we cannot get enough of
out = xformers.ops.memory_efficient_attention(
q, k, v, attn_bias=None, op=self.attention_op
)
if mask is not None:
raise NotImplementedError
out = (
out.unsqueeze(0)
.reshape(b, self.heads, out.shape[1], self.dim_head)
.permute(0, 2, 1, 3)
.reshape(b, out.shape[1], self.heads * self.dim_head)
)
return self.to_out(out)
class BasicTransformerBlock(nn.Module):
ATTENTION_MODES = {
"softmax": CrossAttention, # vanilla attention
"softmax-xformers": MemoryEfficientCrossAttention,
}
def __init__(
self,
dim,
n_heads,
d_head,
dropout=0.0,
context_dim=None,
gated_ff=True,
checkpoint=True,
disable_self_attn=False,
):
super().__init__()
attn_mode = "softmax-xformers" if XFORMERS_IS_AVAILABLE else "softmax"
assert attn_mode in self.ATTENTION_MODES
attn_cls = self.ATTENTION_MODES[attn_mode]
self.disable_self_attn = disable_self_attn
self.attn1 = attn_cls(
query_dim=dim,
heads=n_heads,
dim_head=d_head,
dropout=dropout,
context_dim=context_dim if self.disable_self_attn else None,
) # is a self-attention if not self.disable_self_attn
self.ff = FeedForward(dim, dropout=dropout, glu=gated_ff)
self.attn2 = attn_cls(
query_dim=dim,
context_dim=context_dim,
heads=n_heads,
dim_head=d_head,
dropout=dropout,
) # is self-attn if context is none
self.norm1 = nn.LayerNorm(dim)
self.norm2 = nn.LayerNorm(dim)
self.norm3 = nn.LayerNorm(dim)
self.checkpoint = checkpoint
def forward(self, x, context=None):
return checkpoint_eval(
self._forward, (x, context), self.parameters(), self.checkpoint
)
def _forward(self, x, context=None):
x = x.contiguous() if x.device.type == "mps" else x
x = (
self.attn1(
self.norm1(x), context=context if self.disable_self_attn else None
)
+ x
)
x = self.attn2(self.norm2(x), context=context) + x
x = self.ff(self.norm3(x)) + x
return x
class SpatialTransformer(nn.Module):
"""
Transformer block for image-like data.
First, project the input (aka embedding)
and reshape to b, t, d.
Then apply standard transformer action.
Finally, reshape to image
NEW: use_linear for more efficiency instead of the 1x1 convs.
"""
def __init__(
self,
in_channels,
n_heads,
d_head,
depth=1,
dropout=0.0,
context_dim=None,
disable_self_attn=False,
use_linear=False,
use_checkpoint=True,
):
super().__init__()
if context_dim is not None and not isinstance(context_dim, list):
context_dim = [context_dim]
self.in_channels = in_channels
inner_dim = n_heads * d_head
self.norm = Normalize(in_channels)
if not use_linear:
self.proj_in = nn.Conv2d(
in_channels, inner_dim, kernel_size=1, stride=1, padding=0
)
else:
self.proj_in = nn.Linear(in_channels, inner_dim)
self.transformer_blocks = nn.ModuleList(
[
BasicTransformerBlock(
inner_dim,
n_heads,
d_head,
dropout=dropout,
context_dim=context_dim[d],
disable_self_attn=disable_self_attn,
checkpoint=use_checkpoint,
)
for d in range(depth)
]
)
if not use_linear:
self.proj_out = zero_module(
nn.Conv2d(inner_dim, in_channels, kernel_size=1, stride=1, padding=0)
)
else:
self.proj_out = zero_module(nn.Linear(in_channels, inner_dim))
self.use_linear = use_linear
def forward(self, x, context=None):
# note: if no context is given, cross-attention defaults to self-attention
if not isinstance(context, list):
context = [context]
b, c, h, w = x.shape # noqa
x_in = x
x = self.norm(x)
if self.use_linear:
x = rearrange(x, "b c h w -> b (h w) c").contiguous()
x = self.proj_in(x)
for i, block in enumerate(self.transformer_blocks):
x = block(x, context=context[i])
x = self.proj_out(x)
x = rearrange(x, "b (h w) c -> b c h w", h=h, w=w).contiguous()
else:
x = self.proj_in(x)
x = rearrange(x, "b c h w -> b (h w) c")
for i, block in enumerate(self.transformer_blocks):
x = block(x, context=context[i])
x = rearrange(x, "b (h w) c -> b c h w", h=h, w=w)
x = self.proj_out(x)
return x + x_in