align schedulers

This commit is contained in:
Artiprocher
2024-05-06 23:16:30 +08:00
parent 0965477750
commit 32991d8e3e
2 changed files with 10 additions and 20 deletions

View File

@@ -1,4 +1,4 @@
import torch, math
import torch
class ContinuousODEScheduler():
@@ -7,12 +7,11 @@ class ContinuousODEScheduler():
self.sigma_max = sigma_max
self.sigma_min = sigma_min
self.rho = rho
self.init_noise_sigma = math.sqrt(sigma_max*sigma_max + 1)
self.set_timesteps(num_inference_steps)
def set_timesteps(self, num_inference_steps=100, denoising_strength=1.0):
ramp = torch.linspace(0, denoising_strength, num_inference_steps)
ramp = torch.linspace(1-denoising_strength, 1, num_inference_steps)
min_inv_rho = torch.pow(torch.tensor((self.sigma_min,)), (1 / self.rho))
max_inv_rho = torch.pow(torch.tensor((self.sigma_max,)), (1 / self.rho))
self.sigmas = torch.pow(max_inv_rho + ramp * (min_inv_rho - max_inv_rho), self.rho)
@@ -22,22 +21,17 @@ class ContinuousODEScheduler():
def step(self, model_output, timestep, sample, to_final=False):
timestep_id = torch.argmin((self.timesteps - timestep).abs())
sigma = self.sigmas[timestep_id]
sample *= (sigma*sigma + 1).sqrt()
estimated_sample = -sigma / (sigma*sigma + 1).sqrt() * model_output + 1 / (sigma*sigma + 1) * sample
if to_final or timestep_id + 1 >= len(self.timesteps):
prev_sample = estimated_sample
else:
dt = self.sigmas[timestep_id + 1] - sigma
sigma_ = self.sigmas[timestep_id + 1]
derivative = 1 / sigma * (sample - estimated_sample)
prev_sample = sample + derivative * dt
prev_sample = sample + derivative * (sigma_ - sigma)
prev_sample /= (sigma_*sigma_ + 1).sqrt()
return prev_sample
def scale_model_input(self, sample, timestep):
timestep_id = torch.argmin((self.timesteps - timestep).abs())
sigma = self.sigmas[timestep_id]
sample = sample / (sigma*sigma + 1).sqrt()
return sample
def return_to_timestep(self, timestep, sample, sample_stablized):
# This scheduler doesn't support this function.
@@ -47,6 +41,5 @@ class ContinuousODEScheduler():
def add_noise(self, original_samples, noise, timestep):
timestep_id = torch.argmin((self.timesteps - timestep).abs())
sigma = self.sigmas[timestep_id]
sample = original_samples + noise * sigma
sample = (original_samples + noise * sigma) / (sigma*sigma + 1).sqrt()
return sample