Use @ syntax (#371)

torchani/aev.py

@@ -149,7 +149,7 @@ def neighbor_pairs(padding_mask, coordinates, cell, shifts, cutoff):
     shifts_all = torch.cat([shifts_center, shifts_outide])
     p1_all = torch.cat([p1_center, p1])
     p2_all = torch.cat([p2_center, p2])
-    shift_values = torch.mm(shifts_all.to(cell.dtype), cell)
+    shift_values = shifts_all.to(cell.dtype) @ cell
 
     # step 5, compute distances, and find all pairs within cutoff
     distances = (coordinates.index_select(1, p1_all) - coordinates.index_select(1, p2_all) + shift_values).norm(2, -1)
@@ -241,7 +241,7 @@ def compute_aev(species, coordinates, cell, shifts, triu_index, constants, sizes
     coordinates = coordinates.flatten(0, 1)
     species1 = species[atom_index1]
     species2 = species[atom_index2]
-    shift_values = torch.mm(shifts.to(cell.dtype), cell)
+    shift_values = shifts.to(cell.dtype) @ cell
 
     vec = coordinates.index_select(0, atom_index1) - coordinates.index_select(0, atom_index2) + shift_values
     distances = vec.norm(2, -1)