Minor cleanup (#45)

* cleanup
* codacy
* move merge_tensors to utils.py

pina/utils.py

@@ -1,9 +1,11 @@
 """Utils module"""
+from functools import reduce
+
 
 def number_parameters(model, aggregate=True, only_trainable=True): #TODO: check
     """
     Return the number of parameters of a given `model`.
-    
+
     :param torch.nn.Module model: the torch module to inspect.
     :param bool aggregate: if True the return values is an integer corresponding
         to the total amount of parameters of whole model. If False, it returns a
@@ -25,3 +27,19 @@ def number_parameters(model, aggregate=True, only_trainable=True): #TODO: check
         tmp = sum(tmp.values())
 
     return tmp
+
+
+def merge_tensors(tensors):  # name to be changed
+    if tensors:
+        return reduce(merge_two_tensors, tensors[1:], tensors[0])
+    raise ValueError("Expected at least one tensor")
+
+
+def merge_two_tensors(tensor1, tensor2):
+    n1 = tensor1.shape[0]
+    n2 = tensor2.shape[0]
+
+    tensor1 = LabelTensor(tensor1.repeat(n2, 1), labels=tensor1.labels)
+    tensor2 = LabelTensor(tensor2.repeat_interleave(n1, dim=0),
+                            labels=tensor2.labels)
+    return tensor1.append(tensor2)