Adding features to label tensor class (#29)

* adding label.setter for runtime check on labels

pina/label_tensor.py

@@ -66,7 +66,25 @@ class LabelTensor(torch.Tensor):
                 'the tensor has not the same number of columns of '
                 'the passed labels.'
             )
-        self.labels = labels
+        self._labels = labels
+
+    @property
+    def labels(self):
+        """Property decorator for labels
+
+        :return: labels of self
+        :rtype: list
+        """
+        return self._labels
+
+    @labels.setter
+    def labels(self, labels):
+        if len(labels) != self.shape[1]: # small check
+            raise ValueError(
+                'the tensor has not the same number of columns of '
+                'the passed labels.')
+
+        self._labels = labels   # assign the label
 
     def clone(self, *args, **kwargs):
         """
@@ -120,7 +138,6 @@ class LabelTensor(torch.Tensor):
         extracted_tensor = new_data.as_subclass(LabelTensor)
         extracted_tensor.labels = new_labels
 
-
         return extracted_tensor
 
     def append(self, lt, mode='std'):

tests/test_label_tensor.py

@@ -20,6 +20,8 @@ def test_labels():
     tensor = LabelTensor(data, labels)
     assert isinstance(tensor, torch.Tensor)
     assert tensor.labels == labels
+    with pytest.raises(ValueError):
+        tensor.labels = labels[:-1]
 
 
 def test_extract():