fix bug network

pina/model/network.py

@@ -56,6 +56,9 @@ class Network(torch.nn.Module):
         :param torch.Tensor x: Input of the network.
         :return torch.Tensor: Output of the network.
         """
+        # only labeltensors as input
+        assert isinstance(x, LabelTensor), "Expected LabelTensor as input to the model."
+
         # extract torch.Tensor from corresponding label
         # in case `input_variables = []` all points are used
         if self._input_variables:
@@ -65,22 +68,20 @@ class Network(torch.nn.Module):
         for feature in self._extra_features:
             x = x.append(feature(x))
 
-        # convert LabelTensor to torch.Tensor
-        x = x.as_subclass(torch.Tensor)
-
-        # perform forward pass (using torch.Tensor) + converting to LabelTensor
+        # perform forward pass + converting to LabelTensor
         output = self._model(x).as_subclass(LabelTensor)
 
         # set the labels for LabelTensor
         output.labels = self._output_variables
 
         return output
-
+    
+    # TODO to remove in next releases (only used in GAROM solver)
     def forward_map(self, x):
         """
         Forward method for Network class when the input is
-        a tuple. This class implements the standard forward method,
-        and it adds the possibility to pass extra features.
+        a tuple. This class is simply a forward with the input casted as a
+        tuple or list :class`torch.Tensor`.
         All the PINA models ``forward`` s are overriden
         by this class, to enable :class:`pina.label_tensor.LabelTensor` labels
         extraction.