From 8e74efad01af41c08edd0f57067ae1a14b915d54 Mon Sep 17 00:00:00 2001 From: Cheng Lu Date: Wed, 7 Dec 2022 22:03:58 +0800 Subject: [PATCH] Add Singlestep DPM-Solver (singlestep high-order schedulers) (#1442) * add singlestep dpmsolver * fix a style typo * fix a style typo * add docs * finish Co-authored-by: Patrick von Platen --- docs/source/api/schedulers.mdx | 6 + src/diffusers/__init__.py | 1 + src/diffusers/schedulers/__init__.py | 1 + .../scheduling_dpmsolver_singlestep.py | 599 ++++++++++++++++++ src/diffusers/utils/__init__.py | 1 + src/diffusers/utils/dummy_pt_objects.py | 15 + tests/test_scheduler.py | 177 ++++++ 7 files changed, 800 insertions(+) create mode 100644 src/diffusers/schedulers/scheduling_dpmsolver_singlestep.py diff --git a/docs/source/api/schedulers.mdx b/docs/source/api/schedulers.mdx index 82c4641cd791..0e702f2069a3 100644 --- a/docs/source/api/schedulers.mdx +++ b/docs/source/api/schedulers.mdx @@ -70,6 +70,12 @@ Original paper can be found [here](https://arxiv.org/abs/2010.02502). [[autodoc]] DDPMScheduler +#### Singlestep DPM-Solver + +Original paper can be found [here](https://arxiv.org/abs/2206.00927) and the [improved version](https://arxiv.org/abs/2211.01095). The original implementation can be found [here](https://github.com/LuChengTHU/dpm-solver). + +[[autodoc]] DPMSolverSinglestepScheduler + #### Multistep DPM-Solver Original paper can be found [here](https://arxiv.org/abs/2206.00927) and the [improved version](https://arxiv.org/abs/2211.01095). The original implementation can be found [here](https://github.com/LuChengTHU/dpm-solver). diff --git a/src/diffusers/__init__.py b/src/diffusers/__init__.py index c4dc3e50e424..6b743e8f7031 100644 --- a/src/diffusers/__init__.py +++ b/src/diffusers/__init__.py @@ -44,6 +44,7 @@ DDIMScheduler, DDPMScheduler, DPMSolverMultistepScheduler, + DPMSolverSinglestepScheduler, EulerAncestralDiscreteScheduler, EulerDiscreteScheduler, HeunDiscreteScheduler, diff --git a/src/diffusers/schedulers/__init__.py b/src/diffusers/schedulers/__init__.py index e3069f1eed28..424c93bbf331 100644 --- a/src/diffusers/schedulers/__init__.py +++ b/src/diffusers/schedulers/__init__.py @@ -20,6 +20,7 @@ from .scheduling_ddim import DDIMScheduler from .scheduling_ddpm import DDPMScheduler from .scheduling_dpmsolver_multistep import DPMSolverMultistepScheduler + from .scheduling_dpmsolver_singlestep import DPMSolverSinglestepScheduler from .scheduling_euler_ancestral_discrete import EulerAncestralDiscreteScheduler from .scheduling_euler_discrete import EulerDiscreteScheduler from .scheduling_heun_discrete import HeunDiscreteScheduler diff --git a/src/diffusers/schedulers/scheduling_dpmsolver_singlestep.py b/src/diffusers/schedulers/scheduling_dpmsolver_singlestep.py new file mode 100644 index 000000000000..771a34b20357 --- /dev/null +++ b/src/diffusers/schedulers/scheduling_dpmsolver_singlestep.py @@ -0,0 +1,599 @@ +# Copyright 2022 TSAIL Team and The HuggingFace Team. All rights reserved. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +# DISCLAIMER: This file is strongly influenced by https://github.com/LuChengTHU/dpm-solver + +import math +from typing import List, Optional, Tuple, Union + +import numpy as np +import torch + +from ..configuration_utils import ConfigMixin, register_to_config +from ..utils import _COMPATIBLE_STABLE_DIFFUSION_SCHEDULERS +from .scheduling_utils import SchedulerMixin, SchedulerOutput + + +def betas_for_alpha_bar(num_diffusion_timesteps, max_beta=0.999): + """ + Create a beta schedule that discretizes the given alpha_t_bar function, which defines the cumulative product of + (1-beta) over time from t = [0,1]. + + Contains a function alpha_bar that takes an argument t and transforms it to the cumulative product of (1-beta) up + to that part of the diffusion process. + + + Args: + num_diffusion_timesteps (`int`): the number of betas to produce. + max_beta (`float`): the maximum beta to use; use values lower than 1 to + prevent singularities. + + Returns: + betas (`np.ndarray`): the betas used by the scheduler to step the model outputs + """ + + def alpha_bar(time_step): + return math.cos((time_step + 0.008) / 1.008 * math.pi / 2) ** 2 + + betas = [] + for i in range(num_diffusion_timesteps): + t1 = i / num_diffusion_timesteps + t2 = (i + 1) / num_diffusion_timesteps + betas.append(min(1 - alpha_bar(t2) / alpha_bar(t1), max_beta)) + return torch.tensor(betas, dtype=torch.float32) + + +class DPMSolverSinglestepScheduler(SchedulerMixin, ConfigMixin): + """ + DPM-Solver (and the improved version DPM-Solver++) is a fast dedicated high-order solver for diffusion ODEs with + the convergence order guarantee. Empirically, sampling by DPM-Solver with only 20 steps can generate high-quality + samples, and it can generate quite good samples even in only 10 steps. + + For more details, see the original paper: https://arxiv.org/abs/2206.00927 and https://arxiv.org/abs/2211.01095 + + Currently, we support the singlestep DPM-Solver for both noise prediction models and data prediction models. We + recommend to use `solver_order=2` for guided sampling, and `solver_order=3` for unconditional sampling. + + We also support the "dynamic thresholding" method in Imagen (https://arxiv.org/abs/2205.11487). For pixel-space + diffusion models, you can set both `algorithm_type="dpmsolver++"` and `thresholding=True` to use the dynamic + thresholding. Note that the thresholding method is unsuitable for latent-space diffusion models (such as + stable-diffusion). + + [`~ConfigMixin`] takes care of storing all config attributes that are passed in the scheduler's `__init__` + function, such as `num_train_timesteps`. They can be accessed via `scheduler.config.num_train_timesteps`. + [`SchedulerMixin`] provides general loading and saving functionality via the [`SchedulerMixin.save_pretrained`] and + [`~SchedulerMixin.from_pretrained`] functions. + + Args: + num_train_timesteps (`int`): number of diffusion steps used to train the model. + beta_start (`float`): the starting `beta` value of inference. + beta_end (`float`): the final `beta` value. + beta_schedule (`str`): + the beta schedule, a mapping from a beta range to a sequence of betas for stepping the model. Choose from + `linear`, `scaled_linear`, or `squaredcos_cap_v2`. + trained_betas (`np.ndarray`, optional): + option to pass an array of betas directly to the constructor to bypass `beta_start`, `beta_end` etc. + solver_order (`int`, default `2`): + the order of DPM-Solver; can be `1` or `2` or `3`. We recommend to use `solver_order=2` for guided + sampling, and `solver_order=3` for unconditional sampling. + prediction_type (`str`, default `epsilon`): + indicates whether the model predicts the noise (epsilon), or the data / `x0`. One of `epsilon`, `sample`, + or `v-prediction`. + thresholding (`bool`, default `False`): + whether to use the "dynamic thresholding" method (introduced by Imagen, https://arxiv.org/abs/2205.11487). + For pixel-space diffusion models, you can set both `algorithm_type=dpmsolver++` and `thresholding=True` to + use the dynamic thresholding. Note that the thresholding method is unsuitable for latent-space diffusion + models (such as stable-diffusion). + dynamic_thresholding_ratio (`float`, default `0.995`): + the ratio for the dynamic thresholding method. Default is `0.995`, the same as Imagen + (https://arxiv.org/abs/2205.11487). + sample_max_value (`float`, default `1.0`): + the threshold value for dynamic thresholding. Valid only when `thresholding=True` and + `algorithm_type="dpmsolver++`. + algorithm_type (`str`, default `dpmsolver++`): + the algorithm type for the solver. Either `dpmsolver` or `dpmsolver++`. The `dpmsolver` type implements the + algorithms in https://arxiv.org/abs/2206.00927, and the `dpmsolver++` type implements the algorithms in + https://arxiv.org/abs/2211.01095. We recommend to use `dpmsolver++` with `solver_order=2` for guided + sampling (e.g. stable-diffusion). + solver_type (`str`, default `midpoint`): + the solver type for the second-order solver. Either `midpoint` or `heun`. The solver type slightly affects + the sample quality, especially for small number of steps. We empirically find that `midpoint` solvers are + slightly better, so we recommend to use the `midpoint` type. + lower_order_final (`bool`, default `True`): + whether to use lower-order solvers in the final steps. For singlestep schedulers, we recommend to enable + this to use up all the function evaluations. + + """ + + _compatibles = _COMPATIBLE_STABLE_DIFFUSION_SCHEDULERS.copy() + order = 1 + + @register_to_config + def __init__( + self, + num_train_timesteps: int = 1000, + beta_start: float = 0.0001, + beta_end: float = 0.02, + beta_schedule: str = "linear", + trained_betas: Optional[np.ndarray] = None, + solver_order: int = 2, + prediction_type: str = "epsilon", + thresholding: bool = False, + dynamic_thresholding_ratio: float = 0.995, + sample_max_value: float = 1.0, + algorithm_type: str = "dpmsolver++", + solver_type: str = "midpoint", + lower_order_final: bool = True, + ): + if trained_betas is not None: + self.betas = torch.tensor(trained_betas, dtype=torch.float32) + elif beta_schedule == "linear": + self.betas = torch.linspace(beta_start, beta_end, num_train_timesteps, dtype=torch.float32) + elif beta_schedule == "scaled_linear": + # this schedule is very specific to the latent diffusion model. + self.betas = ( + torch.linspace(beta_start**0.5, beta_end**0.5, num_train_timesteps, dtype=torch.float32) ** 2 + ) + elif beta_schedule == "squaredcos_cap_v2": + # Glide cosine schedule + self.betas = betas_for_alpha_bar(num_train_timesteps) + else: + raise NotImplementedError(f"{beta_schedule} does is not implemented for {self.__class__}") + + self.alphas = 1.0 - self.betas + self.alphas_cumprod = torch.cumprod(self.alphas, dim=0) + # Currently we only support VP-type noise schedule + self.alpha_t = torch.sqrt(self.alphas_cumprod) + self.sigma_t = torch.sqrt(1 - self.alphas_cumprod) + self.lambda_t = torch.log(self.alpha_t) - torch.log(self.sigma_t) + + # standard deviation of the initial noise distribution + self.init_noise_sigma = 1.0 + + # settings for DPM-Solver + if algorithm_type not in ["dpmsolver", "dpmsolver++"]: + raise NotImplementedError(f"{algorithm_type} does is not implemented for {self.__class__}") + if solver_type not in ["midpoint", "heun"]: + raise NotImplementedError(f"{solver_type} does is not implemented for {self.__class__}") + + # setable values + self.num_inference_steps = None + timesteps = np.linspace(0, num_train_timesteps - 1, num_train_timesteps, dtype=np.float32)[::-1].copy() + self.timesteps = torch.from_numpy(timesteps) + self.model_outputs = [None] * solver_order + self.sample = None + self.order_list = self.get_order_list(num_train_timesteps) + + def get_order_list(self, num_inference_steps: int) -> List[int]: + """ + Computes the solver order at each time step. + + Args: + num_inference_steps (`int`): + the number of diffusion steps used when generating samples with a pre-trained model. + """ + steps = num_inference_steps + order = self.solver_order + if self.lower_order_final: + if order == 3: + if steps % 3 == 0: + orders = [1, 2, 3] * (steps // 3 - 1) + [1, 2] + [1] + elif steps % 3 == 1: + orders = [1, 2, 3] * (steps // 3) + [1] + else: + orders = [1, 2, 3] * (steps // 3) + [1, 2] + elif order == 2: + if steps % 2 == 0: + orders = [1, 2] * (steps // 2) + else: + orders = [1, 2] * (steps // 2) + [1] + elif order == 1: + orders = [1] * steps + else: + if order == 3: + orders = [1, 2, 3] * (steps // 3) + elif order == 2: + orders = [1, 2] * (steps // 2) + elif order == 1: + orders = [1] * steps + return orders + + def set_timesteps(self, num_inference_steps: int, device: Union[str, torch.device] = None): + """ + Sets the timesteps used for the diffusion chain. Supporting function to be run before inference. + + Args: + num_inference_steps (`int`): + the number of diffusion steps used when generating samples with a pre-trained model. + device (`str` or `torch.device`, optional): + the device to which the timesteps should be moved to. If `None`, the timesteps are not moved. + """ + self.num_inference_steps = num_inference_steps + timesteps = ( + np.linspace(0, self.num_train_timesteps - 1, num_inference_steps + 1) + .round()[::-1][:-1] + .copy() + .astype(np.int64) + ) + self.timesteps = torch.from_numpy(timesteps).to(device) + self.model_outputs = [None] * self.config.solver_order + self.sample = None + self.orders = self.get_order_list(num_inference_steps) + + def convert_model_output( + self, model_output: torch.FloatTensor, timestep: int, sample: torch.FloatTensor + ) -> torch.FloatTensor: + """ + Convert the model output to the corresponding type that the algorithm (DPM-Solver / DPM-Solver++) needs. + + DPM-Solver is designed to discretize an integral of the noise prediction model, and DPM-Solver++ is designed to + discretize an integral of the data prediction model. So we need to first convert the model output to the + corresponding type to match the algorithm. + + Note that the algorithm type and the model type is decoupled. That is to say, we can use either DPM-Solver or + DPM-Solver++ for both noise prediction model and data prediction model. + + Args: + model_output (`torch.FloatTensor`): direct output from learned diffusion model. + timestep (`int`): current discrete timestep in the diffusion chain. + sample (`torch.FloatTensor`): + current instance of sample being created by diffusion process. + + Returns: + `torch.FloatTensor`: the converted model output. + """ + # DPM-Solver++ needs to solve an integral of the data prediction model. + if self.config.algorithm_type == "dpmsolver++": + if self.config.prediction_type == "epsilon": + alpha_t, sigma_t = self.alpha_t[timestep], self.sigma_t[timestep] + x0_pred = (sample - sigma_t * model_output) / alpha_t + elif self.config.prediction_type == "sample": + x0_pred = model_output + elif self.config.prediction_type == "v_prediction": + alpha_t, sigma_t = self.alpha_t[timestep], self.sigma_t[timestep] + x0_pred = alpha_t * sample - sigma_t * model_output + else: + raise ValueError( + f"prediction_type given as {self.config.prediction_type} must be one of `epsilon`, `sample`, or" + " `v_prediction` for the DPMSolverSinglestepScheduler." + ) + + if self.config.thresholding: + # Dynamic thresholding in https://arxiv.org/abs/2205.11487 + dtype = x0_pred.dtype + dynamic_max_val = torch.quantile( + torch.abs(x0_pred).reshape((x0_pred.shape[0], -1)).float(), + self.config.dynamic_thresholding_ratio, + dim=1, + ) + dynamic_max_val = torch.maximum( + dynamic_max_val, + self.config.sample_max_value * torch.ones_like(dynamic_max_val).to(dynamic_max_val.device), + )[(...,) + (None,) * (x0_pred.ndim - 1)] + x0_pred = torch.clamp(x0_pred, -dynamic_max_val, dynamic_max_val) / dynamic_max_val + x0_pred = x0_pred.to(dtype) + return x0_pred + # DPM-Solver needs to solve an integral of the noise prediction model. + elif self.config.algorithm_type == "dpmsolver": + if self.config.prediction_type == "epsilon": + return model_output + elif self.config.prediction_type == "sample": + alpha_t, sigma_t = self.alpha_t[timestep], self.sigma_t[timestep] + epsilon = (sample - alpha_t * model_output) / sigma_t + return epsilon + elif self.config.prediction_type == "v_prediction": + alpha_t, sigma_t = self.alpha_t[timestep], self.sigma_t[timestep] + epsilon = alpha_t * model_output + sigma_t * sample + return epsilon + else: + raise ValueError( + f"prediction_type given as {self.config.prediction_type} must be one of `epsilon`, `sample`, or" + " `v_prediction` for the DPMSolverSinglestepScheduler." + ) + + def dpm_solver_first_order_update( + self, + model_output: torch.FloatTensor, + timestep: int, + prev_timestep: int, + sample: torch.FloatTensor, + ) -> torch.FloatTensor: + """ + One step for the first-order DPM-Solver (equivalent to DDIM). + + See https://arxiv.org/abs/2206.00927 for the detailed derivation. + + Args: + model_output (`torch.FloatTensor`): direct output from learned diffusion model. + timestep (`int`): current discrete timestep in the diffusion chain. + prev_timestep (`int`): previous discrete timestep in the diffusion chain. + sample (`torch.FloatTensor`): + current instance of sample being created by diffusion process. + + Returns: + `torch.FloatTensor`: the sample tensor at the previous timestep. + """ + lambda_t, lambda_s = self.lambda_t[prev_timestep], self.lambda_t[timestep] + alpha_t, alpha_s = self.alpha_t[prev_timestep], self.alpha_t[timestep] + sigma_t, sigma_s = self.sigma_t[prev_timestep], self.sigma_t[timestep] + h = lambda_t - lambda_s + if self.config.algorithm_type == "dpmsolver++": + x_t = (sigma_t / sigma_s) * sample - (alpha_t * (torch.exp(-h) - 1.0)) * model_output + elif self.config.algorithm_type == "dpmsolver": + x_t = (alpha_t / alpha_s) * sample - (sigma_t * (torch.exp(h) - 1.0)) * model_output + return x_t + + def singlestep_dpm_solver_second_order_update( + self, + model_output_list: List[torch.FloatTensor], + timestep_list: List[int], + prev_timestep: int, + sample: torch.FloatTensor, + ) -> torch.FloatTensor: + """ + One step for the second-order singlestep DPM-Solver. + + It computes the solution at time `prev_timestep` from the time `timestep_list[-2]`. + + Args: + model_output_list (`List[torch.FloatTensor]`): + direct outputs from learned diffusion model at current and latter timesteps. + timestep (`int`): current and latter discrete timestep in the diffusion chain. + prev_timestep (`int`): previous discrete timestep in the diffusion chain. + sample (`torch.FloatTensor`): + current instance of sample being created by diffusion process. + + Returns: + `torch.FloatTensor`: the sample tensor at the previous timestep. + """ + t, s0, s1 = prev_timestep, timestep_list[-1], timestep_list[-2] + m0, m1 = model_output_list[-1], model_output_list[-2] + lambda_t, lambda_s0, lambda_s1 = self.lambda_t[t], self.lambda_t[s0], self.lambda_t[s1] + alpha_t, alpha_s1 = self.alpha_t[t], self.alpha_t[s1] + sigma_t, sigma_s1 = self.sigma_t[t], self.sigma_t[s1] + h, h_0 = lambda_t - lambda_s1, lambda_s0 - lambda_s1 + r0 = h_0 / h + D0, D1 = m1, (1.0 / r0) * (m0 - m1) + if self.config.algorithm_type == "dpmsolver++": + # See https://arxiv.org/abs/2211.01095 for detailed derivations + if self.config.solver_type == "midpoint": + x_t = ( + (sigma_t / sigma_s1) * sample + - (alpha_t * (torch.exp(-h) - 1.0)) * D0 + - 0.5 * (alpha_t * (torch.exp(-h) - 1.0)) * D1 + ) + elif self.config.solver_type == "heun": + x_t = ( + (sigma_t / sigma_s1) * sample + - (alpha_t * (torch.exp(-h) - 1.0)) * D0 + + (alpha_t * ((torch.exp(-h) - 1.0) / h + 1.0)) * D1 + ) + elif self.config.algorithm_type == "dpmsolver": + # See https://arxiv.org/abs/2206.00927 for detailed derivations + if self.config.solver_type == "midpoint": + x_t = ( + (alpha_t / alpha_s1) * sample + - (sigma_t * (torch.exp(h) - 1.0)) * D0 + - 0.5 * (sigma_t * (torch.exp(h) - 1.0)) * D1 + ) + elif self.config.solver_type == "heun": + x_t = ( + (alpha_t / alpha_s1) * sample + - (sigma_t * (torch.exp(h) - 1.0)) * D0 + - (sigma_t * ((torch.exp(h) - 1.0) / h - 1.0)) * D1 + ) + return x_t + + def singlestep_dpm_solver_third_order_update( + self, + model_output_list: List[torch.FloatTensor], + timestep_list: List[int], + prev_timestep: int, + sample: torch.FloatTensor, + ) -> torch.FloatTensor: + """ + One step for the third-order singlestep DPM-Solver. + + It computes the solution at time `prev_timestep` from the time `timestep_list[-3]`. + + Args: + model_output_list (`List[torch.FloatTensor]`): + direct outputs from learned diffusion model at current and latter timesteps. + timestep (`int`): current and latter discrete timestep in the diffusion chain. + prev_timestep (`int`): previous discrete timestep in the diffusion chain. + sample (`torch.FloatTensor`): + current instance of sample being created by diffusion process. + + Returns: + `torch.FloatTensor`: the sample tensor at the previous timestep. + """ + t, s0, s1, s2 = prev_timestep, timestep_list[-1], timestep_list[-2], timestep_list[-3] + m0, m1, m2 = model_output_list[-1], model_output_list[-2], model_output_list[-3] + lambda_t, lambda_s0, lambda_s1, lambda_s2 = ( + self.lambda_t[t], + self.lambda_t[s0], + self.lambda_t[s1], + self.lambda_t[s2], + ) + alpha_t, alpha_s2 = self.alpha_t[t], self.alpha_t[s2] + sigma_t, sigma_s2 = self.sigma_t[t], self.sigma_t[s2] + h, h_0, h_1 = lambda_t - lambda_s2, lambda_s0 - lambda_s2, lambda_s1 - lambda_s2 + r0, r1 = h_0 / h, h_1 / h + D0 = m2 + D1_0, D1_1 = (1.0 / r1) * (m1 - m2), (1.0 / r0) * (m0 - m2) + D1 = (r0 * D1_0 - r1 * D1_1) / (r0 - r1) + D2 = 2.0 * (D1_1 - D1_0) / (r0 - r1) + if self.config.algorithm_type == "dpmsolver++": + # See https://arxiv.org/abs/2206.00927 for detailed derivations + if self.config.solver_type == "midpoint": + x_t = ( + (sigma_t / sigma_s2) * sample + - (alpha_t * (torch.exp(-h) - 1.0)) * D0 + + (alpha_t * ((torch.exp(-h) - 1.0) / h + 1.0)) * D1_1 + ) + elif self.config.solver_type == "heun": + x_t = ( + (sigma_t / sigma_s2) * sample + - (alpha_t * (torch.exp(-h) - 1.0)) * D0 + + (alpha_t * ((torch.exp(-h) - 1.0) / h + 1.0)) * D1 + - (alpha_t * ((torch.exp(-h) - 1.0 + h) / h**2 - 0.5)) * D2 + ) + elif self.config.algorithm_type == "dpmsolver": + # See https://arxiv.org/abs/2206.00927 for detailed derivations + if self.config.solver_type == "midpoint": + x_t = ( + (alpha_t / alpha_s2) * sample + - (sigma_t * (torch.exp(h) - 1.0)) * D0 + - (sigma_t * ((torch.exp(h) - 1.0) / h - 1.0)) * D1_1 + ) + elif self.config.solver_type == "heun": + x_t = ( + (alpha_t / alpha_s2) * sample + - (sigma_t * (torch.exp(h) - 1.0)) * D0 + - (sigma_t * ((torch.exp(h) - 1.0) / h - 1.0)) * D1 + - (sigma_t * ((torch.exp(h) - 1.0 - h) / h**2 - 0.5)) * D2 + ) + return x_t + + def singlestep_dpm_solver_update( + self, + model_output_list: List[torch.FloatTensor], + timestep_list: List[int], + prev_timestep: int, + sample: torch.FloatTensor, + order: int, + ) -> torch.FloatTensor: + """ + One step for the singlestep DPM-Solver. + + Args: + model_output_list (`List[torch.FloatTensor]`): + direct outputs from learned diffusion model at current and latter timesteps. + timestep (`int`): current and latter discrete timestep in the diffusion chain. + prev_timestep (`int`): previous discrete timestep in the diffusion chain. + sample (`torch.FloatTensor`): + current instance of sample being created by diffusion process. + order (`int`): + the solver order at this step. + + Returns: + `torch.FloatTensor`: the sample tensor at the previous timestep. + """ + if order == 1: + return self.dpm_solver_first_order_update(model_output_list[-1], timestep_list[-1], prev_timestep, sample) + elif order == 2: + return self.singlestep_dpm_solver_second_order_update( + model_output_list, timestep_list, prev_timestep, sample + ) + elif order == 3: + return self.singlestep_dpm_solver_third_order_update( + model_output_list, timestep_list, prev_timestep, sample + ) + else: + raise ValueError(f"Order must be 1, 2, 3, got {order}") + + def step( + self, + model_output: torch.FloatTensor, + timestep: int, + sample: torch.FloatTensor, + return_dict: bool = True, + ) -> Union[SchedulerOutput, Tuple]: + """ + Step function propagating the sample with the singlestep DPM-Solver. + + Args: + model_output (`torch.FloatTensor`): direct output from learned diffusion model. + timestep (`int`): current discrete timestep in the diffusion chain. + sample (`torch.FloatTensor`): + current instance of sample being created by diffusion process. + return_dict (`bool`): option for returning tuple rather than SchedulerOutput class + + Returns: + [`~scheduling_utils.SchedulerOutput`] or `tuple`: [`~scheduling_utils.SchedulerOutput`] if `return_dict` is + True, otherwise a `tuple`. When returning a tuple, the first element is the sample tensor. + + """ + if self.num_inference_steps is None: + raise ValueError( + "Number of inference steps is 'None', you need to run 'set_timesteps' after creating the scheduler" + ) + + if isinstance(timestep, torch.Tensor): + timestep = timestep.to(self.timesteps.device) + step_index = (self.timesteps == timestep).nonzero() + if len(step_index) == 0: + step_index = len(self.timesteps) - 1 + else: + step_index = step_index.item() + prev_timestep = 0 if step_index == len(self.timesteps) - 1 else self.timesteps[step_index + 1] + + model_output = self.convert_model_output(model_output, timestep, sample) + for i in range(self.config.solver_order - 1): + self.model_outputs[i] = self.model_outputs[i + 1] + self.model_outputs[-1] = model_output + + order = self.order_list[step_index] + # For single-step solvers, we use the initial value at each time with order = 1. + if order == 1: + self.sample = sample + + timestep_list = [self.timesteps[step_index - i] for i in range(order - 1, 0, -1)] + [timestep] + prev_sample = self.singlestep_dpm_solver_update( + self.model_outputs, timestep_list, prev_timestep, self.sample, order + ) + + if not return_dict: + return (prev_sample,) + + return SchedulerOutput(prev_sample=prev_sample) + + def scale_model_input(self, sample: torch.FloatTensor, *args, **kwargs) -> torch.FloatTensor: + """ + Ensures interchangeability with schedulers that need to scale the denoising model input depending on the + current timestep. + + Args: + sample (`torch.FloatTensor`): input sample + + Returns: + `torch.FloatTensor`: scaled input sample + """ + return sample + + def add_noise( + self, + original_samples: torch.FloatTensor, + noise: torch.FloatTensor, + timesteps: torch.IntTensor, + ) -> torch.FloatTensor: + # Make sure alphas_cumprod and timestep have same device and dtype as original_samples + self.alphas_cumprod = self.alphas_cumprod.to(device=original_samples.device, dtype=original_samples.dtype) + timesteps = timesteps.to(original_samples.device) + + sqrt_alpha_prod = self.alphas_cumprod[timesteps] ** 0.5 + sqrt_alpha_prod = sqrt_alpha_prod.flatten() + while len(sqrt_alpha_prod.shape) < len(original_samples.shape): + sqrt_alpha_prod = sqrt_alpha_prod.unsqueeze(-1) + + sqrt_one_minus_alpha_prod = (1 - self.alphas_cumprod[timesteps]) ** 0.5 + sqrt_one_minus_alpha_prod = sqrt_one_minus_alpha_prod.flatten() + while len(sqrt_one_minus_alpha_prod.shape) < len(original_samples.shape): + sqrt_one_minus_alpha_prod = sqrt_one_minus_alpha_prod.unsqueeze(-1) + + noisy_samples = sqrt_alpha_prod * original_samples + sqrt_one_minus_alpha_prod * noise + return noisy_samples + + def __len__(self): + return self.config.num_train_timesteps diff --git a/src/diffusers/utils/__init__.py b/src/diffusers/utils/__init__.py index ad47ecc1a10a..f30a7ad906e7 100644 --- a/src/diffusers/utils/__init__.py +++ b/src/diffusers/utils/__init__.py @@ -90,6 +90,7 @@ "HeunDiscreteScheduler", "EulerAncestralDiscreteScheduler", "DPMSolverMultistepScheduler", + "DPMSolverSinglestepScheduler", ] diff --git a/src/diffusers/utils/dummy_pt_objects.py b/src/diffusers/utils/dummy_pt_objects.py index a3719a765c96..d8b7001bfd78 100644 --- a/src/diffusers/utils/dummy_pt_objects.py +++ b/src/diffusers/utils/dummy_pt_objects.py @@ -362,6 +362,21 @@ def from_pretrained(cls, *args, **kwargs): requires_backends(cls, ["torch"]) +class DPMSolverSinglestepScheduler(metaclass=DummyObject): + _backends = ["torch"] + + def __init__(self, *args, **kwargs): + requires_backends(self, ["torch"]) + + @classmethod + def from_config(cls, *args, **kwargs): + requires_backends(cls, ["torch"]) + + @classmethod + def from_pretrained(cls, *args, **kwargs): + requires_backends(cls, ["torch"]) + + class EulerAncestralDiscreteScheduler(metaclass=DummyObject): _backends = ["torch"] diff --git a/tests/test_scheduler.py b/tests/test_scheduler.py index a78bd81c826b..efe1a3aa470f 100755 --- a/tests/test_scheduler.py +++ b/tests/test_scheduler.py @@ -28,6 +28,7 @@ DDIMScheduler, DDPMScheduler, DPMSolverMultistepScheduler, + DPMSolverSinglestepScheduler, EulerAncestralDiscreteScheduler, EulerDiscreteScheduler, HeunDiscreteScheduler, @@ -870,6 +871,182 @@ def test_full_loop_with_no_set_alpha_to_one(self): assert abs(result_mean.item() - 0.1941) < 1e-3 +class DPMSolverSinglestepSchedulerTest(SchedulerCommonTest): + scheduler_classes = (DPMSolverSinglestepScheduler,) + forward_default_kwargs = (("num_inference_steps", 25),) + + def get_scheduler_config(self, **kwargs): + config = { + "num_train_timesteps": 1000, + "beta_start": 0.0001, + "beta_end": 0.02, + "beta_schedule": "linear", + "solver_order": 2, + "prediction_type": "epsilon", + "thresholding": False, + "sample_max_value": 1.0, + "algorithm_type": "dpmsolver++", + "solver_type": "midpoint", + } + + config.update(**kwargs) + return config + + def check_over_configs(self, time_step=0, **config): + kwargs = dict(self.forward_default_kwargs) + num_inference_steps = kwargs.pop("num_inference_steps", None) + sample = self.dummy_sample + residual = 0.1 * sample + dummy_past_residuals = [residual + 0.2, residual + 0.15, residual + 0.10] + + for scheduler_class in self.scheduler_classes: + scheduler_config = self.get_scheduler_config(**config) + scheduler = scheduler_class(**scheduler_config) + scheduler.set_timesteps(num_inference_steps) + # copy over dummy past residuals + scheduler.model_outputs = dummy_past_residuals[: scheduler.config.solver_order] + + with tempfile.TemporaryDirectory() as tmpdirname: + scheduler.save_config(tmpdirname) + new_scheduler = scheduler_class.from_pretrained(tmpdirname) + new_scheduler.set_timesteps(num_inference_steps) + # copy over dummy past residuals + new_scheduler.model_outputs = dummy_past_residuals[: new_scheduler.config.solver_order] + + output, new_output = sample, sample + for t in range(time_step, time_step + scheduler.config.solver_order + 1): + output = scheduler.step(residual, t, output, **kwargs).prev_sample + new_output = new_scheduler.step(residual, t, new_output, **kwargs).prev_sample + + assert torch.sum(torch.abs(output - new_output)) < 1e-5, "Scheduler outputs are not identical" + + def test_from_save_pretrained(self): + pass + + def check_over_forward(self, time_step=0, **forward_kwargs): + kwargs = dict(self.forward_default_kwargs) + num_inference_steps = kwargs.pop("num_inference_steps", None) + sample = self.dummy_sample + residual = 0.1 * sample + dummy_past_residuals = [residual + 0.2, residual + 0.15, residual + 0.10] + + for scheduler_class in self.scheduler_classes: + scheduler_config = self.get_scheduler_config() + scheduler = scheduler_class(**scheduler_config) + scheduler.set_timesteps(num_inference_steps) + + # copy over dummy past residuals (must be after setting timesteps) + scheduler.model_outputs = dummy_past_residuals[: scheduler.config.solver_order] + + with tempfile.TemporaryDirectory() as tmpdirname: + scheduler.save_config(tmpdirname) + new_scheduler = scheduler_class.from_pretrained(tmpdirname) + # copy over dummy past residuals + new_scheduler.set_timesteps(num_inference_steps) + + # copy over dummy past residual (must be after setting timesteps) + new_scheduler.model_outputs = dummy_past_residuals[: new_scheduler.config.solver_order] + + output = scheduler.step(residual, time_step, sample, **kwargs).prev_sample + new_output = new_scheduler.step(residual, time_step, sample, **kwargs).prev_sample + + assert torch.sum(torch.abs(output - new_output)) < 1e-5, "Scheduler outputs are not identical" + + def full_loop(self, **config): + scheduler_class = self.scheduler_classes[0] + scheduler_config = self.get_scheduler_config(**config) + scheduler = scheduler_class(**scheduler_config) + + num_inference_steps = 10 + model = self.dummy_model() + sample = self.dummy_sample_deter + scheduler.set_timesteps(num_inference_steps) + + for i, t in enumerate(scheduler.timesteps): + residual = model(sample, t) + sample = scheduler.step(residual, t, sample).prev_sample + + return sample + + def test_timesteps(self): + for timesteps in [25, 50, 100, 999, 1000]: + self.check_over_configs(num_train_timesteps=timesteps) + + def test_thresholding(self): + self.check_over_configs(thresholding=False) + for order in [1, 2, 3]: + for solver_type in ["midpoint", "heun"]: + for threshold in [0.5, 1.0, 2.0]: + for prediction_type in ["epsilon", "sample"]: + self.check_over_configs( + thresholding=True, + prediction_type=prediction_type, + sample_max_value=threshold, + algorithm_type="dpmsolver++", + solver_order=order, + solver_type=solver_type, + ) + + def test_prediction_type(self): + for prediction_type in ["epsilon", "v_prediction"]: + self.check_over_configs(prediction_type=prediction_type) + + def test_solver_order_and_type(self): + for algorithm_type in ["dpmsolver", "dpmsolver++"]: + for solver_type in ["midpoint", "heun"]: + for order in [1, 2, 3]: + for prediction_type in ["epsilon", "sample"]: + self.check_over_configs( + solver_order=order, + solver_type=solver_type, + prediction_type=prediction_type, + algorithm_type=algorithm_type, + ) + sample = self.full_loop( + solver_order=order, + solver_type=solver_type, + prediction_type=prediction_type, + algorithm_type=algorithm_type, + ) + assert not torch.isnan(sample).any(), "Samples have nan numbers" + + def test_lower_order_final(self): + self.check_over_configs(lower_order_final=True) + self.check_over_configs(lower_order_final=False) + + def test_inference_steps(self): + for num_inference_steps in [1, 2, 3, 5, 10, 50, 100, 999, 1000]: + self.check_over_forward(num_inference_steps=num_inference_steps, time_step=0) + + def test_full_loop_no_noise(self): + sample = self.full_loop() + result_mean = torch.mean(torch.abs(sample)) + + assert abs(result_mean.item() - 0.2791) < 1e-3 + + def test_full_loop_with_v_prediction(self): + sample = self.full_loop(prediction_type="v_prediction") + result_mean = torch.mean(torch.abs(sample)) + + assert abs(result_mean.item() - 0.1453) < 1e-3 + + def test_fp16_support(self): + scheduler_class = self.scheduler_classes[0] + scheduler_config = self.get_scheduler_config(thresholding=True, dynamic_thresholding_ratio=0) + scheduler = scheduler_class(**scheduler_config) + + num_inference_steps = 10 + model = self.dummy_model() + sample = self.dummy_sample_deter.half() + scheduler.set_timesteps(num_inference_steps) + + for i, t in enumerate(scheduler.timesteps): + residual = model(sample, t) + sample = scheduler.step(residual, t, sample).prev_sample + + assert sample.dtype == torch.float16 + + class DPMSolverMultistepSchedulerTest(SchedulerCommonTest): scheduler_classes = (DPMSolverMultistepScheduler,) forward_default_kwargs = (("num_inference_steps", 25),)