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from ..diffusionmodules.upscaling import ImageConcatWithNoiseAugmentation
from ..diffusionmodules.openaimodel import Timestep
import torch
class CLIPEmbeddingNoiseAugmentation(ImageConcatWithNoiseAugmentation):
def __init__(self, *args, clip_stats_path=None, timestep_dim=256, **kwargs):
super().__init__(*args, **kwargs)
if clip_stats_path is None:
clip_mean, clip_std = torch.zeros(timestep_dim), torch.ones(timestep_dim)
else:
clip_mean, clip_std = torch.load(clip_stats_path, map_location="cpu")
self.register_buffer("data_mean", clip_mean[None, :], persistent=False)
self.register_buffer("data_std", clip_std[None, :], persistent=False)
self.time_embed = Timestep(timestep_dim)
def scale(self, x):
# re-normalize to centered mean and unit variance
x = (x - self.data_mean.to(x.device)) * 1. / self.data_std.to(x.device)
return x
def unscale(self, x):
# back to original data stats
x = (x * self.data_std.to(x.device)) + self.data_mean.to(x.device)
return x
def forward(self, x, noise_level=None, seed=None):
if noise_level is None:
noise_level = torch.randint(0, self.max_noise_level, (x.shape[0],), device=x.device).long()
else:
assert isinstance(noise_level, torch.Tensor)
x = self.scale(x)
z = self.q_sample(x, noise_level, seed=seed)
z = self.unscale(z)
noise_level = self.time_embed(noise_level)
return z, noise_level
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