fix bug network

pina/model/fno.py

@@ -2,6 +2,8 @@ import torch
 import torch.nn as nn
 from ..utils import check_consistency
 from .layers.fourier import FourierBlock1D, FourierBlock2D, FourierBlock3D
+from pina import LabelTensor
+import warnings
 
 
 class FNO(torch.nn.Module):
@@ -69,7 +71,7 @@ class FNO(torch.nn.Module):
         elif dimensions == 3:
             fourier_layer = FourierBlock3D
         else:
-            NotImplementedError('FNO implemented only for 1D/2D/3D data.')
+            raise NotImplementedError('FNO implemented only for 1D/2D/3D data.')
 
         # Here we build the FNO by stacking Fourier Blocks
 
@@ -137,6 +139,9 @@ class FNO(torch.nn.Module):
         :return: The output tensor obtained from the FNO.
         :rtype: torch.Tensor
         """
+        if isinstance(x, LabelTensor): #TODO remove when Network is fixed
+            warnings.warn('LabelTensor passed as input is not allowed, casting LabelTensor to Torch.Tensor')
+            x = x.as_subclass(torch.Tensor)
 
         # lifting the input in higher dimensional space
         x = self._lifting_net(x)