Merge pull request #5797 from mcmonkey4eva/dpm2-a-fix

Add a workaround patch for DPM2 a issue

modules/sd_samplers.py

@@ -454,6 +454,9 @@ class KDiffusionSampler:
         else:
             sigmas = self.model_wrap.get_sigmas(steps)
 
+        if self.funcname in ['sample_dpm_2_ancestral', 'sample_dpm_2']:
+            sigmas = torch.cat([sigmas[:-2], sigmas[-1:]])
+
         sigma_sched = sigmas[steps - t_enc - 1:]
         xi = x + noise * sigma_sched[0]
         
@@ -494,6 +497,9 @@ class KDiffusionSampler:
 
         x = x * sigmas[0]
 
+        if self.funcname in ['sample_dpm_2_ancestral', 'sample_dpm_2']:
+            sigmas = torch.cat([sigmas[:-2], sigmas[-1:]])
+
         extra_params_kwargs = self.initialize(p)
         if 'sigma_min' in inspect.signature(self.func).parameters:
             extra_params_kwargs['sigma_min'] = self.model_wrap.sigmas[0].item()