diff --git a/comfy/k_diffusion/sampling.py b/comfy/k_diffusion/sampling.py index c809d39f..94d7a576 100644 --- a/comfy/k_diffusion/sampling.py +++ b/comfy/k_diffusion/sampling.py @@ -605,3 +605,46 @@ def sample_dpmpp_2m(model, x, sigmas, extra_args=None, callback=None, disable=No x = (sigma_fn(t_next) / sigma_fn(t)) * x - (-h).expm1() * denoised_d old_denoised = denoised return x + +@torch.no_grad() +def sample_dpmpp_2m_sde(model, x, sigmas, extra_args=None, callback=None, disable=None, eta=1., s_noise=1., noise_sampler=None, solver_type='midpoint'): + """DPM-Solver++(2M) SDE.""" + + if solver_type not in {'heun', 'midpoint'}: + raise ValueError('solver_type must be \'heun\' or \'midpoint\'') + + sigma_min, sigma_max = sigmas[sigmas > 0].min(), sigmas.max() + noise_sampler = BrownianTreeNoiseSampler(x, sigma_min, sigma_max) if noise_sampler is None else noise_sampler + extra_args = {} if extra_args is None else extra_args + s_in = x.new_ones([x.shape[0]]) + + old_denoised = None + h_last = None + + for i in trange(len(sigmas) - 1, disable=disable): + denoised = model(x, sigmas[i] * s_in, **extra_args) + if callback is not None: + callback({'x': x, 'i': i, 'sigma': sigmas[i], 'sigma_hat': sigmas[i], 'denoised': denoised}) + if sigmas[i + 1] == 0: + # Denoising step + x = denoised + else: + # DPM-Solver++(2M) SDE + t, s = -sigmas[i].log(), -sigmas[i + 1].log() + h = s - t + eta_h = eta * h + + x = sigmas[i + 1] / sigmas[i] * (-eta_h).exp() * x + (-h - eta_h).expm1().neg() * denoised + + if old_denoised is not None: + r = h_last / h + if solver_type == 'heun': + x = x + ((-h - eta_h).expm1().neg() / (-h - eta_h) + 1) * (1 / r) * (denoised - old_denoised) + elif solver_type == 'midpoint': + x = x + 0.5 * (-h - eta_h).expm1().neg() * (1 / r) * (denoised - old_denoised) + + x = x + noise_sampler(sigmas[i], sigmas[i + 1]) * sigmas[i + 1] * (-2 * eta_h).expm1().neg().sqrt() * s_noise + + old_denoised = denoised + h_last = h + return x diff --git a/comfy/samplers.py b/comfy/samplers.py index fccf254e..1fb928f8 100644 --- a/comfy/samplers.py +++ b/comfy/samplers.py @@ -495,10 +495,10 @@ def encode_adm(noise_augmentor, conds, batch_size, device): class KSampler: - SCHEDULERS = ["normal", "karras", "simple", "ddim_uniform"] + SCHEDULERS = ["normal", "karras", "exponential", "simple", "ddim_uniform"] SAMPLERS = ["euler", "euler_ancestral", "heun", "dpm_2", "dpm_2_ancestral", "lms", "dpm_fast", "dpm_adaptive", "dpmpp_2s_ancestral", "dpmpp_sde", - "dpmpp_2m", "ddim", "uni_pc", "uni_pc_bh2"] + "dpmpp_2m", "dpmpp_2m_sde", "ddim", "uni_pc", "uni_pc_bh2"] def __init__(self, model, steps, device, sampler=None, scheduler=None, denoise=None, model_options={}): self.model = model @@ -532,6 +532,8 @@ class KSampler: if self.scheduler == "karras": sigmas = k_diffusion_sampling.get_sigmas_karras(n=steps, sigma_min=self.sigma_min, sigma_max=self.sigma_max) + elif self.scheduler == "exponential": + sigmas = k_diffusion_sampling.get_sigmas_exponential(n=steps, sigma_min=self.sigma_min, sigma_max=self.sigma_max) elif self.scheduler == "normal": sigmas = self.model_wrap.get_sigmas(steps) elif self.scheduler == "simple":