Update sampler.py

fix import

Author: rromb

ldm/models/diffusion/dpm_solver/sampler.py

@@ -2,7 +2,7 @@
 
 import torch
 
-from .solver import NoiseScheduleVP, model_wrapper, DPM_Solver
+from .dpm_solver import NoiseScheduleVP, model_wrapper, DPM_Solver
 
 
 class DPMSolverSampler(object):
@@ -79,4 +79,4 @@ def sample(self,
         dpm_solver = DPM_Solver(model_fn, ns, predict_x0=True, thresholding=False)
         x = dpm_solver.sample(img, steps=S, skip_type="time_uniform", method="multistep", order=2, lower_order_final=True)
 
-        return x.to(device), None
+        return x.to(device), None