From 49a37b054ea7c1cdd8c0d7c44f3809ab8bee0693 Mon Sep 17 00:00:00 2001
From: Volpeon <git@volpeon.ink>
Date: Thu, 6 Oct 2022 17:15:22 +0200
Subject: Update

---
 schedulers/scheduling_euler_a.py | 45 +++++++++++++++++++++++++++++++++-------
 1 file changed, 38 insertions(+), 7 deletions(-)

(limited to 'schedulers')

diff --git a/schedulers/scheduling_euler_a.py b/schedulers/scheduling_euler_a.py
index c6436d8..13ea6b3 100644
--- a/schedulers/scheduling_euler_a.py
+++ b/schedulers/scheduling_euler_a.py
@@ -171,6 +171,9 @@ class EulerAScheduler(SchedulerMixin, ConfigMixin):
         self.alphas = 1.0 - self.betas
         self.alphas_cumprod = torch.cumprod(self.alphas, dim=0)
 
+        # standard deviation of the initial noise distribution
+        self.init_noise_sigma = 1.0
+
         # setable values
         self.num_inference_steps = None
         self.timesteps = np.arange(0, num_train_timesteps)[::-1]
@@ -190,13 +193,33 @@ class EulerAScheduler(SchedulerMixin, ConfigMixin):
         self.num_inference_steps = num_inference_steps
         self.DSsigmas = ((1 - self.alphas_cumprod) / self.alphas_cumprod) ** 0.5
         self.sigmas = get_sigmas(self.DSsigmas, self.num_inference_steps).to(device=device)
-        self.timesteps = np.arange(0, self.num_inference_steps)
+        self.timesteps = self.sigmas[:-1]
+        self.is_scale_input_called = False
+
+    def scale_model_input(self, sample: torch.FloatTensor, timestep: int) -> 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
+            timestep (`int`, optional): current timestep
+        Returns:
+            `torch.FloatTensor`: scaled input sample
+        """
+        if isinstance(timestep, torch.Tensor):
+            timestep = timestep.to(self.timesteps.device)
+        if self.is_scale_input_called:
+            return sample
+        step_index = (self.timesteps == timestep).nonzero().item()
+        sigma = self.sigmas[step_index]
+        sample = sample * sigma
+        self.is_scale_input_called = True
+        return sample
 
     def step(
         self,
         model_output: torch.FloatTensor,
-        timestep: int,
-        timestep_prev: int,
+        timestep: Union[float, torch.FloatTensor],
         sample: torch.FloatTensor,
         generator: torch.Generator = None,
         return_dict: bool = True,
@@ -219,8 +242,13 @@ class EulerAScheduler(SchedulerMixin, ConfigMixin):
             returning a tuple, the first element is the sample tensor.
 
         """
-        s = self.sigmas[timestep]
-        s_prev = self.sigmas[timestep_prev]
+        if isinstance(timestep, torch.Tensor):
+            timestep = timestep.to(self.timesteps.device)
+        step_index = (self.timesteps == timestep).nonzero().item()
+        step_prev_index = step_index + 1
+
+        s = self.sigmas[step_index]
+        s_prev = self.sigmas[step_prev_index]
         latents = sample
 
         sigma_down, sigma_up = get_ancestral_step(s, s_prev)
@@ -271,14 +299,17 @@ class EulerAScheduler(SchedulerMixin, ConfigMixin):
         self,
         original_samples: torch.FloatTensor,
         noise: torch.FloatTensor,
-        timesteps: torch.IntTensor,
+        timesteps: torch.FloatTensor,
     ) -> torch.FloatTensor:
         sigmas = self.sigmas.to(original_samples.device)
+        schedule_timesteps = self.timesteps.to(original_samples.device)
         timesteps = timesteps.to(original_samples.device)
+        step_indices = [(schedule_timesteps == t).nonzero().item() for t in timesteps]
 
-        sigma = sigmas[timesteps].flatten()
+        sigma = sigmas[step_indices].flatten()
         while len(sigma.shape) < len(original_samples.shape):
             sigma = sigma.unsqueeze(-1)
 
         noisy_samples = original_samples + noise * sigma
+        self.is_scale_input_called = True
         return noisy_samples
-- 
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