diff --git a/source/train/calculator.py b/source/train/calculator.py
index 37fb7ad412..de439c3f78 100644
--- a/source/train/calculator.py
+++ b/source/train/calculator.py
@@ -42,10 +42,13 @@ def __init__(self, model, label="DP", type_dict=None, **kwargs):
 
     def calculate(self, atoms=None, properties=["energy", "forces", "stress"], system_changes=all_changes):
         coord = atoms.get_positions().reshape([1, -1])
-        cell = atoms.get_cell().reshape([1, -1])
+        if sum(atoms.get_pbc())>0:
+           cell = atoms.get_cell().reshape([1, -1])
+        else:
+           cell = None
         symbols = atoms.get_chemical_symbols()
         atype = [self.type_dict[k] for k in symbols]
-        e, f, v = self.dp.eval(coord, cell, atype)
+        e, f, v = self.dp.eval(coords=coord, cells=cell, atom_types=atype)
         self.results['energy'] = e[0]
         self.results['forces'] = f[0]
         self.results['stress'] = v[0]