sat/sgm/modules/diffusionmodules/wrappers.py

import torch
import torch.nn as nn
from packaging import version

OPENAIUNETWRAPPER = "sgm.modules.diffusionmodules.wrappers.OpenAIWrapper"


class IdentityWrapper(nn.Module):
    def __init__(self, diffusion_model, compile_model: bool = False, dtype: torch.dtype = torch.float32):
        super().__init__()
        compile = (
            torch.compile
            if (version.parse(torch.__version__) >= version.parse("2.0.0")) and compile_model
            else lambda x: x
        )
        self.diffusion_model = compile(diffusion_model)
        self.dtype = dtype

    def forward(self, *args, **kwargs):
        return self.diffusion_model(*args, **kwargs)


class OpenAIWrapper(IdentityWrapper):
    def forward(self, x: torch.Tensor, t: torch.Tensor, c: dict, **kwargs) -> torch.Tensor:
        for key in c:
            c[key] = c[key].to(self.dtype)

        if x.dim() == 4:
            x = torch.cat((x, c.get("concat", torch.Tensor([]).type_as(x))), dim=1)
        elif x.dim() == 5:
            x = torch.cat((x, c.get("concat", torch.Tensor([]).type_as(x))), dim=2)
        else:
            raise ValueError("Input tensor must be 4D or 5D")

        return self.diffusion_model(
            x,
            timesteps=t,
            context=c.get("crossattn", None),
            y=c.get("vector", None),
            **kwargs,
        )