mirror of
https://github.com/invoke-ai/InvokeAI
synced 2024-08-30 20:32:17 +00:00
135 lines
3.6 KiB
Python
135 lines
3.6 KiB
Python
import math
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from typing import Callable
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import torch
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from einops import rearrange, repeat
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from torch import Tensor
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from .model import Flux
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from .modules.conditioner import HFEncoder
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def get_noise(
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num_samples: int,
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height: int,
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width: int,
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device: torch.device,
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dtype: torch.dtype,
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seed: int,
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):
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return torch.randn(
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num_samples,
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16,
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# allow for packing
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2 * math.ceil(height / 16),
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2 * math.ceil(width / 16),
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device=device,
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dtype=dtype,
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generator=torch.Generator(device=device).manual_seed(seed),
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)
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def prepare(t5: HFEncoder, clip: HFEncoder, img: Tensor, prompt: str | list[str]) -> dict[str, Tensor]:
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bs, c, h, w = img.shape
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if bs == 1 and not isinstance(prompt, str):
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bs = len(prompt)
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img = rearrange(img, "b c (h ph) (w pw) -> b (h w) (c ph pw)", ph=2, pw=2)
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if img.shape[0] == 1 and bs > 1:
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img = repeat(img, "1 ... -> bs ...", bs=bs)
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img_ids = torch.zeros(h // 2, w // 2, 3)
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img_ids[..., 1] = img_ids[..., 1] + torch.arange(h // 2)[:, None]
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img_ids[..., 2] = img_ids[..., 2] + torch.arange(w // 2)[None, :]
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img_ids = repeat(img_ids, "h w c -> b (h w) c", b=bs)
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if isinstance(prompt, str):
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prompt = [prompt]
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txt = t5(prompt)
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if txt.shape[0] == 1 and bs > 1:
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txt = repeat(txt, "1 ... -> bs ...", bs=bs)
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txt_ids = torch.zeros(bs, txt.shape[1], 3)
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vec = clip(prompt)
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if vec.shape[0] == 1 and bs > 1:
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vec = repeat(vec, "1 ... -> bs ...", bs=bs)
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return {
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"img": img,
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"img_ids": img_ids.to(img.device),
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"txt": txt.to(img.device),
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"txt_ids": txt_ids.to(img.device),
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"vec": vec.to(img.device),
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}
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def time_shift(mu: float, sigma: float, t: Tensor):
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return math.exp(mu) / (math.exp(mu) + (1 / t - 1) ** sigma)
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def get_lin_function(x1: float = 256, y1: float = 0.5, x2: float = 4096, y2: float = 1.15) -> Callable[[float], float]:
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m = (y2 - y1) / (x2 - x1)
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b = y1 - m * x1
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return lambda x: m * x + b
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def get_schedule(
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num_steps: int,
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image_seq_len: int,
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base_shift: float = 0.5,
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max_shift: float = 1.15,
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shift: bool = True,
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) -> list[float]:
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# extra step for zero
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timesteps = torch.linspace(1, 0, num_steps + 1)
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# shifting the schedule to favor high timesteps for higher signal images
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if shift:
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# eastimate mu based on linear estimation between two points
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mu = get_lin_function(y1=base_shift, y2=max_shift)(image_seq_len)
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timesteps = time_shift(mu, 1.0, timesteps)
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return timesteps.tolist()
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def denoise(
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model: Flux,
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# model input
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img: Tensor,
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img_ids: Tensor,
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txt: Tensor,
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txt_ids: Tensor,
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vec: Tensor,
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# sampling parameters
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timesteps: list[float],
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guidance: float = 4.0,
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):
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# this is ignored for schnell
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guidance_vec = torch.full((img.shape[0],), guidance, device=img.device, dtype=img.dtype)
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for t_curr, t_prev in zip(timesteps[:-1], timesteps[1:], strict=False):
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t_vec = torch.full((img.shape[0],), t_curr, dtype=img.dtype, device=img.device)
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pred = model(
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img=img,
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img_ids=img_ids,
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txt=txt,
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txt_ids=txt_ids,
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y=vec,
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timesteps=t_vec,
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guidance=guidance_vec,
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)
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img = img + (t_prev - t_curr) * pred
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return img
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def unpack(x: Tensor, height: int, width: int) -> Tensor:
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return rearrange(
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x,
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"b (h w) (c ph pw) -> b c (h ph) (w pw)",
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h=math.ceil(height / 16),
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w=math.ceil(width / 16),
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ph=2,
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pw=2,
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)
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