Update sampling.py

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yoinked 2024-06-25 22:22:09 -07:00 committed by GitHub
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@ -996,5 +996,45 @@ def sample_euler_ancestral_pp(model, x, sigmas, extra_args=None, callback=None,
dt = sigma_down - sigmas[i] dt = sigma_down - sigmas[i]
x = x + d * dt x = x + d * dt
if sigmas[i + 1] > 0: if sigmas[i + 1] > 0:
@torch.no_grad()
def sample_dpmpp_2s_ancestral_pp(model, x, sigmas, extra_args=None, callback=None, disable=None, eta=1., s_noise=1., noise_sampler=None):
"""Ancestral sampling with DPM-Solver++(2S) second-order steps."""
extra_args = {} if extra_args is None else extra_args
noise_sampler = default_noise_sampler(x) if noise_sampler is None else noise_sampler
temp = [0]
def post_cfg_function(args):
temp[0] = args["uncond_denoised"]
return args["denoised"]
model_options = extra_args.get("model_options", {}).copy()
extra_args["model_options"] = comfy.model_patcher.set_model_options_post_cfg_function(model_options, post_cfg_function, disable_cfg1_optimization=True)
s_in = x.new_ones([x.shape[0]])
sigma_fn = lambda t: t.neg().exp()
t_fn = lambda sigma: sigma.log().neg()
for i in trange(len(sigmas) - 1, disable=disable):
denoised = model(x, sigmas[i] * s_in, **extra_args)
sigma_down, sigma_up = get_ancestral_step(sigmas[i], sigmas[i + 1], eta=eta)
if callback is not None:
callback({'x': x, 'i': i, 'sigma': sigmas[i], 'sigma_hat': sigmas[i], 'denoised': denoised})
if sigma_down == 0:
# Euler method
d = to_d(x - denoised + temp[0], sigmas[i], denoised)
dt = sigma_down - sigmas[i]
x = x + d * dt
else:
# DPM-Solver++(2S)
t, t_next = t_fn(sigmas[i]), t_fn(sigma_down)
r = 1 / 2
h = t_next - t
s = t + r * h
x_2 = (sigma_fn(s) / sigma_fn(t)) * (x + (denoised - temp[0])) - (-h * r).expm1() * denoised
denoised_2 = model(x_2, sigma_fn(s) * s_in, **extra_args)
x = (sigma_fn(t_next) / sigma_fn(t)) * (x + (denoised - temp[0])) - (-h).expm1() * denoised_2
# Noise addition
if sigmas[i + 1] > 0:
x = x + noise_sampler(sigmas[i], sigmas[i + 1]) * s_noise * sigma_up x = x + noise_sampler(sigmas[i], sigmas[i + 1]) * s_noise * sigma_up
return x return x