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StarPilot/tinygrad_repo/extra/models/unet.py
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firestar5683 22a8575199 Vendor dependencies and resources for standalone builds
Keep official openpilot ancestry and dependency licenses. Store resources directly in Git, remove LFS setup requirements, and leave the downloadable big model outside the source tree.
2026-10-03 21:01:18 +00:00

263 lines
9.9 KiB
Python

from tinygrad import Tensor, Device, dtypes, nn
from typing import Optional, Union, List, Any, Tuple, Callable
import math
# allow for monkeypatching
Linear, Conv2d, GroupNorm, LayerNorm = nn.Linear, nn.Conv2d, nn.GroupNorm, nn.LayerNorm
attention, gelu, mixed_precision_dtype = Tensor.scaled_dot_product_attention, Tensor.gelu, dtypes.float16
# https://github.com/Stability-AI/generative-models/blob/fbdc58cab9f4ee2be7a5e1f2e2787ecd9311942f/sgm/modules/diffusionmodules/util.py#L207
def timestep_embedding(timesteps:Tensor, dim:int, max_period=10000):
half = dim // 2
freqs = (-math.log(max_period) * Tensor.arange(half) / half).exp()
args = timesteps.unsqueeze(1) * freqs.unsqueeze(0)
out = Tensor.cat(args.cos(), args.sin(), dim=-1)
return out.cast(mixed_precision_dtype) if mixed_precision_dtype in Device[Device.DEFAULT].renderer.supported_dtypes() else out
class ResBlock:
def __init__(self, channels:int, emb_channels:int, out_channels:int, num_groups:int=32):
self.in_layers = [
GroupNorm(num_groups, channels),
Tensor.silu,
Conv2d(channels, out_channels, 3, padding=1),
]
self.emb_layers = [
Tensor.silu,
Linear(emb_channels, out_channels),
]
self.out_layers = [
GroupNorm(num_groups, out_channels),
Tensor.silu,
lambda x: x, # needed for weights loading code to work
Conv2d(out_channels, out_channels, 3, padding=1),
]
self.skip_connection = Conv2d(channels, out_channels, 1) if channels != out_channels else (lambda x: x)
def __call__(self, x:Tensor, emb:Tensor) -> Tensor:
h = x.sequential(self.in_layers)
emb_out = emb.sequential(self.emb_layers)
h = h + emb_out.reshape(*emb_out.shape, 1, 1)
h = h.sequential(self.out_layers)
return self.skip_connection(x) + h
class CrossAttention:
def __init__(self, query_dim:int, ctx_dim:int, n_heads:int, d_head:int):
self.to_q = Linear(query_dim, n_heads*d_head, bias=False)
self.to_k = Linear(ctx_dim, n_heads*d_head, bias=False)
self.to_v = Linear(ctx_dim, n_heads*d_head, bias=False)
self.num_heads = n_heads
self.head_size = d_head
self.attn = attention
self.to_out = [Linear(n_heads*d_head, query_dim)]
def __call__(self, x:Tensor, ctx:Optional[Tensor]=None) -> Tensor:
ctx = x if ctx is None else ctx
q,k,v = self.to_q(x), self.to_k(ctx), self.to_v(ctx)
q,k,v = [y.reshape(x.shape[0], -1, self.num_heads, self.head_size).transpose(1,2) for y in (q,k,v)]
attention = self.attn(q, k, v).transpose(1,2)
h_ = attention.reshape(x.shape[0], -1, self.num_heads * self.head_size)
return h_.sequential(self.to_out)
class GEGLU:
def __init__(self, dim_in:int, dim_out:int):
self.proj = Linear(dim_in, dim_out * 2)
self.gelu = gelu
self.dim_out = dim_out
def __call__(self, x:Tensor) -> Tensor:
x, gate = self.proj(x).chunk(2, dim=-1)
return x * self.gelu(gate)
class FeedForward:
def __init__(self, dim:int, mult:int=4):
self.net: tuple[GEGLU, Callable, nn.Linear] = (
GEGLU(dim, dim*mult),
lambda x: x, # needed for weights loading code to work
Linear(dim*mult, dim)
)
def __call__(self, x:Tensor) -> Tensor:
return x.sequential(list(self.net))
class BasicTransformerBlock:
def __init__(self, dim:int, ctx_dim:int, n_heads:int, d_head:int):
self.attn1 = CrossAttention(dim, dim, n_heads, d_head)
self.ff = FeedForward(dim)
self.attn2 = CrossAttention(dim, ctx_dim, n_heads, d_head)
self.norm1 = LayerNorm(dim)
self.norm2 = LayerNorm(dim)
self.norm3 = LayerNorm(dim)
def __call__(self, x:Tensor, ctx:Optional[Tensor]=None) -> Tensor:
x = x + self.attn1(self.norm1(x))
x = x + self.attn2(self.norm2(x), ctx=ctx)
x = x + self.ff(self.norm3(x))
return x
# https://github.com/Stability-AI/generative-models/blob/fbdc58cab9f4ee2be7a5e1f2e2787ecd9311942f/sgm/modules/attention.py#L619
class SpatialTransformer:
def __init__(self, channels:int, n_heads:int, d_head:int, ctx_dim:Union[int,List[int]], use_linear:bool, depth:int=1,
norm_eps:float=1e-5):
if isinstance(ctx_dim, int):
ctx_dim = [ctx_dim]*depth
else:
assert isinstance(ctx_dim, list) and depth == len(ctx_dim)
self.norm = GroupNorm(32, channels, eps=norm_eps)
assert channels == n_heads * d_head
self.proj_in = Linear(channels, channels) if use_linear else Conv2d(channels, channels, 1)
self.transformer_blocks = [BasicTransformerBlock(channels, ctx_dim[d], n_heads, d_head) for d in range(depth)]
self.proj_out = Linear(channels, channels) if use_linear else Conv2d(channels, channels, 1)
self.use_linear = use_linear
def __call__(self, x:Tensor, ctx:Optional[Tensor]=None) -> Tensor:
b, c, h, w = x.shape
x_in = x
x = self.norm(x)
ops = [ (lambda z: z.reshape(b, c, h*w).permute(0,2,1)), (lambda z: self.proj_in(z)) ]
x = x.sequential(ops if self.use_linear else ops[::-1])
for block in self.transformer_blocks:
x = block(x, ctx=ctx)
ops = [ (lambda z: self.proj_out(z)), (lambda z: z.permute(0,2,1).reshape(b, c, h, w)) ]
x = x.sequential(ops if self.use_linear else ops[::-1])
return x + x_in
class Downsample:
def __init__(self, channels:int):
self.op = Conv2d(channels, channels, 3, stride=2, padding=1)
def __call__(self, x:Tensor) -> Tensor:
return self.op(x)
class Upsample:
def __init__(self, channels:int):
self.conv = Conv2d(channels, channels, 3, padding=1)
def __call__(self, x:Tensor) -> Tensor:
bs,c,py,px = x.shape
z = x.reshape(bs, c, py, 1, px, 1).expand(bs, c, py, 2, px, 2).reshape(bs, c, py*2, px*2)
return self.conv(z)
# https://github.com/Stability-AI/generative-models/blob/fbdc58cab9f4ee2be7a5e1f2e2787ecd9311942f/sgm/modules/diffusionmodules/openaimodel.py#L472
class UNetModel:
def __init__(self, adm_in_ch:Optional[int], in_ch:int, out_ch:int, model_ch:int, attention_resolutions:List[int], num_res_blocks:int,
channel_mult:List[int], transformer_depth:List[int], ctx_dim:Union[int,List[int]], use_linear:bool=False, d_head:Optional[int]=None,
n_heads:Optional[int]=None, num_groups:int=32, st_norm_eps:float=1e-5):
self.model_ch = model_ch
self.num_res_blocks = [num_res_blocks] * len(channel_mult)
self.attention_resolutions = attention_resolutions
self.d_head = d_head
self.n_heads = n_heads
def get_d_and_n_heads(dims:int) -> Tuple[int,int]:
if self.d_head is None:
assert self.n_heads is not None, f"d_head and n_heads cannot both be None"
return dims // self.n_heads, self.n_heads
else:
assert self.n_heads is None, f"d_head and n_heads cannot both be non-None"
return self.d_head, dims // self.d_head
time_embed_dim = model_ch * 4
self.time_embed = [
Linear(model_ch, time_embed_dim),
Tensor.silu,
Linear(time_embed_dim, time_embed_dim),
]
if adm_in_ch is not None:
self.label_emb = [
[
Linear(adm_in_ch, time_embed_dim),
Tensor.silu,
Linear(time_embed_dim, time_embed_dim),
]
]
self.input_blocks: List[Any] = [
[Conv2d(in_ch, model_ch, 3, padding=1)]
]
input_block_channels = [model_ch]
ch = model_ch
ds = 1
for idx, mult in enumerate(channel_mult):
for _ in range(self.num_res_blocks[idx]):
layers: List[Any] = [
ResBlock(ch, time_embed_dim, model_ch*mult, num_groups),
]
ch = mult * model_ch
if ds in attention_resolutions:
d_head, n_heads = get_d_and_n_heads(ch)
layers.append(SpatialTransformer(ch, n_heads, d_head, ctx_dim, use_linear, depth=transformer_depth[idx], norm_eps=st_norm_eps))
self.input_blocks.append(layers)
input_block_channels.append(ch)
if idx != len(channel_mult) - 1:
self.input_blocks.append([
Downsample(ch),
])
input_block_channels.append(ch)
ds *= 2
d_head, n_heads = get_d_and_n_heads(ch)
self.middle_block: List = [
ResBlock(ch, time_embed_dim, ch, num_groups),
SpatialTransformer(ch, n_heads, d_head, ctx_dim, use_linear, depth=transformer_depth[-1], norm_eps=st_norm_eps),
ResBlock(ch, time_embed_dim, ch, num_groups),
]
self.output_blocks = []
for idx, mult in list(enumerate(channel_mult))[::-1]:
for i in range(self.num_res_blocks[idx] + 1):
ich = input_block_channels.pop()
layers = [
ResBlock(ch + ich, time_embed_dim, model_ch*mult, num_groups),
]
ch = model_ch * mult
if ds in attention_resolutions:
d_head, n_heads = get_d_and_n_heads(ch)
layers.append(SpatialTransformer(ch, n_heads, d_head, ctx_dim, use_linear, depth=transformer_depth[idx], norm_eps=st_norm_eps))
if idx > 0 and i == self.num_res_blocks[idx]:
layers.append(Upsample(ch))
ds //= 2
self.output_blocks.append(layers)
self.out = [
GroupNorm(num_groups, ch),
Tensor.silu,
Conv2d(model_ch, out_ch, 3, padding=1),
]
def __call__(self, x:Tensor, tms:Tensor, ctx:Tensor, y:Optional[Tensor]=None) -> Tensor:
t_emb = timestep_embedding(tms, self.model_ch)
emb = t_emb.sequential(self.time_embed)
if y is not None:
assert y.shape[0] == x.shape[0]
emb = emb + y.sequential(self.label_emb[0])
if mixed_precision_dtype in Device[Device.DEFAULT].renderer.supported_dtypes():
emb = emb.cast(mixed_precision_dtype)
ctx = ctx.cast(mixed_precision_dtype)
x = x .cast(mixed_precision_dtype)
def run(x:Tensor, bb) -> Tensor:
if isinstance(bb, ResBlock): x = bb(x, emb)
elif isinstance(bb, SpatialTransformer): x = bb(x, ctx)
else: x = bb(x)
return x
saved_inputs = []
for b in self.input_blocks:
for bb in b:
x = run(x, bb)
saved_inputs.append(x)
for bb in self.middle_block:
x = run(x, bb)
for b in self.output_blocks:
x = x.cat(saved_inputs.pop(), dim=1)
for bb in b:
x = run(x, bb)
return x.sequential(self.out)