calc_md with pressure 0 corrected

pyiron/lammps/control.py

@@ -223,12 +223,12 @@ def pressure_to_lammps(self, pressure, rotation_matrix):
             pressure = np.array(all_pressures, dtype=float)
 
         # Cell degrees of freedom can be kept fixed using None for the pressure, check where that's done.
-        not_none_mask = [p is not None for p in pressure]
+        not_none_mask = (pressure!=None)
         if not np.any(not_none_mask):
             raise ValueError("Pressure cannot have a length but all be None")
 
         # If necessary, rotate the pressure tensor to the Lammps coordinate frame
-        if np.matrix.trace(rotation_matrix) != 3:
+        if not np.isclose(np.matrix.trace(rotation_matrix), 3):
             if not np.all(not_none_mask):
                 raise ValueError("Cells which are not orthorhombic or rectangular are incompatible with Lammps "
                                  "constant pressure calculations unless the entire pressure tensor is defined."
@@ -491,16 +491,11 @@ def calc_md(
 
         # Set thermodynamic ensemble
         if pressure is not None:  # NPT
-            if not hasattr(pressure, "__len__"):
-                pressure = pressure * np.ones(3)
-            else:
-                pressure = np.array(pressure, dtype=float)
 
-            not_none_mask = [p is not None for p in pressure]
-            if not np.any(not_none_mask):
-                raise ValueError("Pressure cannot be three times None")
+            if np.sum(np.array([pressure]).flatten()!=None)==0:
+                raise ValueError("At least one component of pressure must be other than None")
 
-            if len(pressure) > 6:
+            if hasattr(pressure, "__len__") and len(pressure) > 6:
                 raise ValueError("Pressure must be a float or a vector with length <= 6")
 
             if temperature is None or temperature.min() <= 0:

tests/lammps/test_base.py

@@ -285,6 +285,7 @@ def test_dump_parser_water(self):
             n_print=200,
             pressure=0,
         )
+        self.assertFalse('nan' in self.job_water_dump.input.control['fix___ensemble'])
         file_directory = os.path.join(
             self.execution_path, "..", "static", "lammps_test_files"
         )