DreamCraft3D/extern/ldm_zero123/models/diffusion/sampling_util.py
2023-12-15 17:44:44 +08:00

52 lines
1.6 KiB
Python
Executable File

import numpy as np
import torch
def append_dims(x, target_dims):
"""Appends dimensions to the end of a tensor until it has target_dims dimensions.
From https://github.com/crowsonkb/k-diffusion/blob/master/k_diffusion/utils.py"""
dims_to_append = target_dims - x.ndim
if dims_to_append < 0:
raise ValueError(
f"input has {x.ndim} dims but target_dims is {target_dims}, which is less"
)
return x[(...,) + (None,) * dims_to_append]
def renorm_thresholding(x0, value):
# renorm
pred_max = x0.max()
pred_min = x0.min()
pred_x0 = (x0 - pred_min) / (pred_max - pred_min) # 0 ... 1
pred_x0 = 2 * pred_x0 - 1.0 # -1 ... 1
s = torch.quantile(rearrange(pred_x0, "b ... -> b (...)").abs(), value, dim=-1)
s.clamp_(min=1.0)
s = s.view(-1, *((1,) * (pred_x0.ndim - 1)))
# clip by threshold
# pred_x0 = pred_x0.clamp(-s, s) / s # needs newer pytorch # TODO bring back to pure-gpu with min/max
# temporary hack: numpy on cpu
pred_x0 = (
np.clip(pred_x0.cpu().numpy(), -s.cpu().numpy(), s.cpu().numpy())
/ s.cpu().numpy()
)
pred_x0 = torch.tensor(pred_x0).to(self.model.device)
# re.renorm
pred_x0 = (pred_x0 + 1.0) / 2.0 # 0 ... 1
pred_x0 = (pred_max - pred_min) * pred_x0 + pred_min # orig range
return pred_x0
def norm_thresholding(x0, value):
s = append_dims(x0.pow(2).flatten(1).mean(1).sqrt().clamp(min=value), x0.ndim)
return x0 * (value / s)
def spatial_norm_thresholding(x0, value):
# b c h w
s = x0.pow(2).mean(1, keepdim=True).sqrt().clamp(min=value)
return x0 * (value / s)