Support SVD img2vid model.

comfy/model_sampling.py

@@ -1,7 +1,7 @@
 import torch
 import numpy as np
 from comfy.ldm.modules.diffusionmodules.util import make_beta_schedule
-
+import math
 
 class EPS:
     def calculate_input(self, sigma, noise):
@@ -83,3 +83,47 @@ class ModelSamplingDiscrete(torch.nn.Module):
         percent = 1.0 - percent
         return self.sigma(torch.tensor(percent * 999.0)).item()
 
+
+class ModelSamplingContinuousEDM(torch.nn.Module):
+    def __init__(self, model_config=None):
+        super().__init__()
+        self.sigma_data = 1.0
+
+        if model_config is not None:
+            sampling_settings = model_config.sampling_settings
+        else:
+            sampling_settings = {}
+
+        sigma_min = sampling_settings.get("sigma_min", 0.002)
+        sigma_max = sampling_settings.get("sigma_max", 120.0)
+        self.set_sigma_range(sigma_min, sigma_max)
+
+    def set_sigma_range(self, sigma_min, sigma_max):
+        sigmas = torch.linspace(math.log(sigma_min), math.log(sigma_max), 1000).exp()
+
+        self.register_buffer('sigmas', sigmas) #for compatibility with some schedulers
+        self.register_buffer('log_sigmas', sigmas.log())
+
+    @property
+    def sigma_min(self):
+        return self.sigmas[0]
+
+    @property
+    def sigma_max(self):
+        return self.sigmas[-1]
+
+    def timestep(self, sigma):
+        return 0.25 * sigma.log()
+
+    def sigma(self, timestep):
+        return (timestep / 0.25).exp()
+
+    def percent_to_sigma(self, percent):
+        if percent <= 0.0:
+            return 999999999.9
+        if percent >= 1.0:
+            return 0.0
+        percent = 1.0 - percent
+
+        log_sigma_min = math.log(self.sigma_min)
+        return math.exp((math.log(self.sigma_max) - log_sigma_min) * percent + log_sigma_min)