enable flux pipeline compatible with unipc and dpm-solver (#11908)

* Update pipeline_flux.py

have flux pipeline work with unipc/dpm schedulers

* clean code

* Update scheduling_dpmsolver_multistep.py

* Update scheduling_unipc_multistep.py

* Update pipeline_flux.py

* Update scheduling_deis_multistep.py

* Update scheduling_dpmsolver_singlestep.py

* Apply style fixes

---------
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: YiYi Xu <yixu310@gmail.com>
Co-authored-by: Álvaro Somoza <asomoza@users.noreply.github.com>

src/diffusers/pipelines/flux/pipeline_flux.py

@@ -840,6 +840,8 @@ class FluxPipeline(
 
         # 5. Prepare timesteps
         sigmas = np.linspace(1.0, 1 / num_inference_steps, num_inference_steps) if sigmas is None else sigmas
+        if hasattr(self.scheduler.config, "use_flow_sigmas") and self.scheduler.config.use_flow_sigmas:
+            sigmas = None
         image_seq_len = latents.shape[1]
         mu = calculate_shift(
             image_seq_len,

src/diffusers/schedulers/scheduling_deis_multistep.py

@@ -153,6 +153,8 @@ class DEISMultistepScheduler(SchedulerMixin, ConfigMixin):
         flow_shift: Optional[float] = 1.0,
         timestep_spacing: str = "linspace",
         steps_offset: int = 0,
+        use_dynamic_shifting: bool = False,
+        time_shift_type: str = "exponential",
     ):
         if self.config.use_beta_sigmas and not is_scipy_available():
             raise ImportError("Make sure to install scipy if you want to use beta sigmas.")
@@ -232,7 +234,9 @@ class DEISMultistepScheduler(SchedulerMixin, ConfigMixin):
         """
         self._begin_index = begin_index
 
-    def set_timesteps(self, num_inference_steps: int, device: Union[str, torch.device] = None):
+    def set_timesteps(
+        self, num_inference_steps: int, device: Union[str, torch.device] = None, mu: Optional[float] = None
+    ):
         """
         Sets the discrete timesteps used for the diffusion chain (to be run before inference).
 
@@ -242,6 +246,9 @@ class DEISMultistepScheduler(SchedulerMixin, ConfigMixin):
             device (`str` or `torch.device`, *optional*):
                 The device to which the timesteps should be moved to. If `None`, the timesteps are not moved.
         """
+        if mu is not None:
+            assert self.config.use_dynamic_shifting and self.config.time_shift_type == "exponential"
+            self.config.flow_shift = np.exp(mu)
         # "linspace", "leading", "trailing" corresponds to annotation of Table 2. of https://huggingface.co/papers/2305.08891
         if self.config.timestep_spacing == "linspace":
             timesteps = (

src/diffusers/schedulers/scheduling_dpmsolver_multistep.py

@@ -230,6 +230,8 @@ class DPMSolverMultistepScheduler(SchedulerMixin, ConfigMixin):
         timestep_spacing: str = "linspace",
         steps_offset: int = 0,
         rescale_betas_zero_snr: bool = False,
+        use_dynamic_shifting: bool = False,
+        time_shift_type: str = "exponential",
     ):
         if self.config.use_beta_sigmas and not is_scipy_available():
             raise ImportError("Make sure to install scipy if you want to use beta sigmas.")
@@ -330,6 +332,7 @@ class DPMSolverMultistepScheduler(SchedulerMixin, ConfigMixin):
         self,
         num_inference_steps: int = None,
         device: Union[str, torch.device] = None,
+        mu: Optional[float] = None,
         timesteps: Optional[List[int]] = None,
     ):
         """
@@ -345,6 +348,9 @@ class DPMSolverMultistepScheduler(SchedulerMixin, ConfigMixin):
                 based on the `timestep_spacing` attribute. If `timesteps` is passed, `num_inference_steps` and `sigmas`
                 must be `None`, and `timestep_spacing` attribute will be ignored.
         """
+        if mu is not None:
+            assert self.config.use_dynamic_shifting and self.config.time_shift_type == "exponential"
+            self.config.flow_shift = np.exp(mu)
         if num_inference_steps is None and timesteps is None:
             raise ValueError("Must pass exactly one of `num_inference_steps` or `timesteps`.")
         if num_inference_steps is not None and timesteps is not None:

src/diffusers/schedulers/scheduling_dpmsolver_singlestep.py

@@ -169,6 +169,8 @@ class DPMSolverSinglestepScheduler(SchedulerMixin, ConfigMixin):
         final_sigmas_type: Optional[str] = "zero",  # "zero", "sigma_min"
         lambda_min_clipped: float = -float("inf"),
         variance_type: Optional[str] = None,
+        use_dynamic_shifting: bool = False,
+        time_shift_type: str = "exponential",
     ):
         if self.config.use_beta_sigmas and not is_scipy_available():
             raise ImportError("Make sure to install scipy if you want to use beta sigmas.")
@@ -301,6 +303,7 @@ class DPMSolverSinglestepScheduler(SchedulerMixin, ConfigMixin):
         self,
         num_inference_steps: int = None,
         device: Union[str, torch.device] = None,
+        mu: Optional[float] = None,
         timesteps: Optional[List[int]] = None,
     ):
         """
@@ -316,6 +319,9 @@ class DPMSolverSinglestepScheduler(SchedulerMixin, ConfigMixin):
                 timestep spacing strategy of equal spacing between timesteps schedule is used. If `timesteps` is
                 passed, `num_inference_steps` must be `None`.
         """
+        if mu is not None:
+            assert self.config.use_dynamic_shifting and self.config.time_shift_type == "exponential"
+            self.config.flow_shift = np.exp(mu)
         if num_inference_steps is None and timesteps is None:
             raise ValueError("Must pass exactly one of  `num_inference_steps` or `timesteps`.")
         if num_inference_steps is not None and timesteps is not None:

src/diffusers/schedulers/scheduling_unipc_multistep.py

@@ -212,6 +212,8 @@ class UniPCMultistepScheduler(SchedulerMixin, ConfigMixin):
         steps_offset: int = 0,
         final_sigmas_type: Optional[str] = "zero",  # "zero", "sigma_min"
         rescale_betas_zero_snr: bool = False,
+        use_dynamic_shifting: bool = False,
+        time_shift_type: str = "exponential",
     ):
         if self.config.use_beta_sigmas and not is_scipy_available():
             raise ImportError("Make sure to install scipy if you want to use beta sigmas.")
@@ -298,7 +300,9 @@ class UniPCMultistepScheduler(SchedulerMixin, ConfigMixin):
         """
         self._begin_index = begin_index
 
-    def set_timesteps(self, num_inference_steps: int, device: Union[str, torch.device] = None):
+    def set_timesteps(
+        self, num_inference_steps: int, device: Union[str, torch.device] = None, mu: Optional[float] = None
+    ):
         """
         Sets the discrete timesteps used for the diffusion chain (to be run before inference).
 
@@ -309,6 +313,9 @@ class UniPCMultistepScheduler(SchedulerMixin, ConfigMixin):
                 The device to which the timesteps should be moved to. If `None`, the timesteps are not moved.
         """
         # "linspace", "leading", "trailing" corresponds to annotation of Table 2. of https://huggingface.co/papers/2305.08891
+        if mu is not None:
+            assert self.config.use_dynamic_shifting and self.config.time_shift_type == "exponential"
+            self.config.flow_shift = np.exp(mu)
         if self.config.timestep_spacing == "linspace":
             timesteps = (
                 np.linspace(0, self.config.num_train_timesteps - 1, num_inference_steps + 1)