Emit error when trying to set negative number of empty bands in DFT

pyiron_atomistics/sphinx/base.py

@@ -1075,8 +1075,10 @@ def set_empty_states(self, n_empty_states=None):
             # will be converted later; see load_default_groups
             self.input["EmptyStates"] = "auto"
         else:
-            if n_empty_states < 0:
-                raise ValueError("Number of empty states must be greater than 0")
+            if n_empty_states <= 0:
+                raise ValueError(
+                    f"Number of empty states must be a positive integer, not {n_empty_states}!"
+                )
             self.input["EmptyStates"] = n_empty_states
         self.input.sphinx.PAWHamiltonian.nEmptyStates = self.input["EmptyStates"]
 

pyiron_atomistics/vasp/base.py

@@ -1333,6 +1333,10 @@ def set_empty_states(self, n_empty_states=None):
         """
         n_elect = self.get_nelect()
         if n_empty_states is not None:
+            if n_empty_states <= 0:
+                raise ValueError(
+                    f"Number of empty states must be a positive integer, not {n_empty_states}!"
+                )
             self.input.incar["NBANDS"] = int(round(n_elect / 2)) + int(n_empty_states)
 
     def get_nelect(self):