imaginAIry/imaginairy/modules/sgm/diffusionmodules/guiders.py
2023-11-22 17:20:08 -08:00

101 lines
3.0 KiB
Python

import logging
from abc import ABC, abstractmethod
from typing import Dict, List, Optional, Tuple, Union
import torch
from einops import rearrange, repeat
from imaginairy.utils import default
from imaginairy.vendored.k_diffusion.utils import append_dims
logpy = logging.getLogger(__name__)
class Guider(ABC):
@abstractmethod
def __call__(self, x: torch.Tensor, sigma: float) -> torch.Tensor:
pass
def prepare_inputs(
self, x: torch.Tensor, s: float, c: Dict, uc: Dict
) -> Tuple[torch.Tensor, float, Dict]:
pass
class VanillaCFG(Guider):
def __init__(self, scale: float):
self.scale = scale
def __call__(self, x: torch.Tensor, sigma: torch.Tensor) -> torch.Tensor:
x_u, x_c = x.chunk(2)
x_pred = x_u + self.scale * (x_c - x_u)
return x_pred
def prepare_inputs(self, x, s, c, uc):
c_out = {}
for k in c:
if k in ["vector", "crossattn", "concat"]:
c_out[k] = torch.cat((uc[k], c[k]), 0)
else:
assert c[k] == uc[k]
c_out[k] = c[k]
return torch.cat([x] * 2), torch.cat([s] * 2), c_out
class IdentityGuider(Guider):
def __call__(self, x: torch.Tensor, sigma: float) -> torch.Tensor:
return x
def prepare_inputs(
self, x: torch.Tensor, s: float, c: Dict, uc: Dict
) -> Tuple[torch.Tensor, float, Dict]:
c_out = {}
for k in c:
c_out[k] = c[k]
return x, s, c_out
class LinearPredictionGuider(Guider):
def __init__(
self,
max_scale: float,
num_frames: int,
min_scale: float = 1.0,
additional_cond_keys: Optional[Union[List[str], str]] = None,
):
self.min_scale = min_scale
self.max_scale = max_scale
self.num_frames = num_frames
self.scale = torch.linspace(min_scale, max_scale, num_frames).unsqueeze(0)
additional_cond_keys = default(additional_cond_keys, [])
if isinstance(additional_cond_keys, str):
additional_cond_keys = [additional_cond_keys]
self.additional_cond_keys = additional_cond_keys
def __call__(self, x: torch.Tensor, sigma: torch.Tensor) -> torch.Tensor:
x_u, x_c = x.chunk(2)
x_u = rearrange(x_u, "(b t) ... -> b t ...", t=self.num_frames)
x_c = rearrange(x_c, "(b t) ... -> b t ...", t=self.num_frames)
scale = repeat(self.scale, "1 t -> b t", b=x_u.shape[0])
scale = append_dims(scale, x_u.ndim).to(x_u.device)
return rearrange(x_u + scale * (x_c - x_u), "b t ... -> (b t) ...")
def prepare_inputs(
self, x: torch.Tensor, s: torch.Tensor, c: dict, uc: dict
) -> Tuple[torch.Tensor, torch.Tensor, dict]:
c_out = {}
for k in c:
if k in ["vector", "crossattn", "concat", *self.additional_cond_keys]:
c_out[k] = torch.cat((uc[k], c[k]), 0)
else:
assert c[k] == uc[k]
c_out[k] = c[k]
return torch.cat([x] * 2), torch.cat([s] * 2), c_out