using pbc_diff now in tetrahedral_order parameter calculation, since reference positions will not be periodic images in the default use case

src/mdevaluate/distribution.py

@@ -182,10 +182,10 @@ def tetrahedral_order(
     )
 
     # Connection vectors
-    neighbors_1 -= atoms
+    neighbors_1 = pbc_diff(neighbors_1, atoms, box=atoms.box)
-    neighbors_2 -= atoms
+    neighbors_2 = pbc_diff(neighbors_2, atoms, box=atoms.box)
-    neighbors_3 -= atoms
+    neighbors_3 = pbc_diff(neighbors_3, atoms, box=atoms.box)
-    neighbors_4 -= atoms
+    neighbors_4 = pbc_diff(neighbors_4, atoms, box=atoms.box)
 
     # Normed Connection vectors
     neighbors_1 /= np.linalg.norm(neighbors_1, axis=-1).reshape(-1, 1)