[RF inversion community pipeline] add eta_decay (#10199)

* add decay

* add decay

* style

examples/community/pipeline_flux_rf_inversion.py

@@ -648,6 +648,8 @@ class RFInversionFluxPipeline(
         height: Optional[int] = None,
         width: Optional[int] = None,
         eta: float = 1.0,
+        decay_eta: Optional[bool] = False,
+        eta_decay_power: Optional[float] = 1.0,
         strength: float = 1.0,
         start_timestep: float = 0,
         stop_timestep: float = 0.25,
@@ -880,12 +882,9 @@ class RFInversionFluxPipeline(
                     v_t = -noise_pred
                     v_t_cond = (y_0 - latents) / (1 - t_i)
                     eta_t = eta if start_timestep <= i < stop_timestep else 0.0
-                    if start_timestep <= i < stop_timestep:
-                        # controlled vector field
-                        v_hat_t = v_t + eta * (v_t_cond - v_t)
-
-                    else:
-                        v_hat_t = v_t
+                    if decay_eta:
+                        eta_t = eta_t * (1 - i / num_inference_steps) ** eta_decay_power  # Decay eta over the loop
+                    v_hat_t = v_t + eta_t * (v_t_cond - v_t)
 
                     # SDE Eq: 17 from https://arxiv.org/pdf/2410.10792
                     latents = latents + v_hat_t * (sigmas[i] - sigmas[i + 1])