Importing fix

Author: AleDinve

pina/loss/ntk_weighting.py

@@ -3,9 +3,11 @@
 import torch
 from torch.nn import Module
 from .weighting_interface import WeightingInterface
-from ..operator import grad
 from ..utils import check_consistency
 
+class _NoWeighting(WeightingInterface):
+    def aggregate(self, losses):
+        return sum(losses.values())
 
 class NeuralTangetKernelWeighting(WeightingInterface):
     """