fix floating error

modules/sd_samplers_kdiffusion.py

@@ -89,11 +89,12 @@ def restart_sampler(model, x, sigmas, extra_args=None, callback=None, disable=No
             restart_steps, restart_times, restart_max = restart_list[i + 1]
             min_idx = i + 1
             max_idx = int(torch.argmin(abs(sigmas - restart_max), dim=0))
-            sigma_restart = get_sigmas_karras(restart_steps, sigmas[min_idx], sigmas[max_idx], device=sigmas.device)[:-1] # remove the zero at the end
-            for times in range(restart_times):
-                x = x + torch.randn_like(x) * s_noise * (sigmas[max_idx] ** 2 - sigmas[min_idx] ** 2) ** 0.5
-                for (old_sigma, new_sigma) in zip(sigma_restart[:-1], sigma_restart[1:]):
-                    x = heun_step(x, old_sigma, new_sigma)
+            if max_idx < min_idx:
+                sigma_restart = get_sigmas_karras(restart_steps, sigmas[min_idx], sigmas[max_idx], device=sigmas.device)[:-1] # remove the zero at the end
+                for times in range(restart_times):
+                    x = x + torch.randn_like(x) * s_noise * (sigmas[max_idx] ** 2 - sigmas[min_idx] ** 2) ** 0.5
+                    for (old_sigma, new_sigma) in zip(sigma_restart[:-1], sigma_restart[1:]):
+                        x = heun_step(x, old_sigma, new_sigma)
     return x
 
 samplers_data_k_diffusion = [