diff --git a/modules/sd_samplers_kdiffusion.py b/modules/sd_samplers_kdiffusion.py index db7013f24..ed5e6c79b 100644 --- a/modules/sd_samplers_kdiffusion.py +++ b/modules/sd_samplers_kdiffusion.py @@ -38,20 +38,19 @@ samplers_k_diffusion = [ def restart_sampler(model, x, sigmas, extra_args=None, callback=None, disable=None, s_noise=1.): """Implements restart sampling in Restart Sampling for Improving Generative Processes (2023)""" '''Restart_list format: {min_sigma: [ restart_steps, restart_times, max_sigma]}''' - restart_list = {0.1: [10, 2, 2]} from tqdm.auto import trange extra_args = {} if extra_args is None else extra_args s_in = x.new_ones([x.shape[0]]) step_id = 0 from k_diffusion.sampling import to_d, append_zero - def heun_step(x, old_sigma, new_sigma): + def heun_step(x, old_sigma, new_sigma, second_order = True): nonlocal step_id denoised = model(x, old_sigma * s_in, **extra_args) d = to_d(x, old_sigma, denoised) if callback is not None: callback({'x': x, 'i': step_id, 'sigma': new_sigma, 'sigma_hat': old_sigma, 'denoised': denoised}) dt = new_sigma - old_sigma - if new_sigma == 0: + if new_sigma == 0 or not second_order: # Euler method x = x + d * dt else: @@ -63,11 +62,6 @@ def restart_sampler(model, x, sigmas, extra_args=None, callback=None, disable=No x = x + d_prime * dt step_id += 1 return x - # print(sigmas) - temp_list = dict() - for key, value in restart_list.items(): - temp_list[int(torch.argmin(abs(sigmas - key), dim=0))] = value - restart_list = temp_list def get_sigmas_karras(n, sigma_min, sigma_max, rho=7., device='cpu'): ramp = torch.linspace(0, 1, n).to(device) min_inv_rho = (sigma_min ** (1 / rho)) @@ -78,6 +72,18 @@ def restart_sampler(model, x, sigmas, extra_args=None, callback=None, disable=No max_inv_rho = max_inv_rho.to(device) sigmas = (max_inv_rho + ramp * (min_inv_rho - max_inv_rho)) ** rho return append_zero(sigmas).to(device) + steps = sigmas.shape[0] - 1 + if steps >= 20: + restart_steps = 9 + restart_times = 2 if steps >= 36 else 1 + sigmas = get_sigmas_karras(steps - restart_steps * restart_times, sigmas[-2], sigmas[0], device=sigmas.device) + restart_list = {0.1: [restart_steps + 1, restart_times, 2]} + else: + restart_list = dict() + temp_list = dict() + for key, value in restart_list.items(): + temp_list[int(torch.argmin(abs(sigmas - key), dim=0))] = value + restart_list = temp_list for i in trange(len(sigmas) - 1, disable=disable): x = heun_step(x, sigmas[i], sigmas[i+1]) if i + 1 in restart_list: