Make generic energy_pot of Vasp configurable

Vasp outputs three energies, smeared internal energy, free energy and
smeared internal extrapolated to zero smearing.
This change allows to pick which of them is set as

output/generic/energy_pot

of the job.

Current defaults are smeared internal extrapolated to zero smearing when
vasprun.xml can be read and free energy when OUTCAR is read.

pyiron_atomistics/vasp/base.py

@@ -1927,6 +1927,14 @@ def _eddrmm_backwards_compatibility(eddrmm_value):
         else:
             return eddrmm_value
 
+import enum
+class DftEnergyKind(enum.Enum):
+    ENERGY_FREE = enum.auto()
+    """The full free energy of the electronic system, i.e. smeared internal energy plus entropy."""
+    ENERGY_INTERNAL = enum.auto()
+    """The smeared internal energy of the electronic system."""
+    ENERGY_ZERO = enum.auto()
+    """The internal energy of the electronic system, extrapolated to zero smearing."""
 
 class Output:
     """
@@ -1938,8 +1946,9 @@ class Output:
         charge_density: Gives the charge density of the system
     """
 
-    def __init__(self):
+    def __init__(self, energy_kind=None):
         self._structure = None
+        self._energy_kind = None
         self.outcar = Outcar()
         self.oszicar = Oszicar()
         self.generic_output = GenericOutput()
@@ -2051,8 +2060,20 @@ def collect(self, directory=os.getcwd(), sorted_indices=None):
             log_dict["forces"] = self.vp_new.vasprun_dict["forces"]
             log_dict["cells"] = self.vp_new.vasprun_dict["cells"]
             log_dict["volume"] = np.linalg.det(self.vp_new.vasprun_dict["cells"])
+            # A bug in the xml output of 5.4.4 renders total_*_energies useless
+            # https://www.vasp.at/forum/viewtopic.php?p=19264&hilit=vasprun+energy#p19264
             # log_dict["total_energies"] = self.vp_new.vasprun_dict["total_energies"]
-            log_dict["energy_tot"] = self.vp_new.vasprun_dict["total_energies"]
+            if self._energy_kind is None:
+                self._energy_kind = DftEnergyKind.ENERGY_ZERO
+            VASPRUN_ENERGY_KIND_KEYS = {
+                    DftEnergyKind.ENERGY_FREE: "scf_fr_energies",
+                    DftEnergyKind.ENERGY_INTERNAL: "scf_energies",
+                    DftEnergyKind.ENERGY_ZERO: "scf_0_energies",
+            }
+            energy_key = VASPRUN_ENERGY_KIND_KEYS[self._energy_kind]
+            log_dict["energy_tot"] = np.array([
+                    energy[-1] for energy in self.vp_new.vasprun_dict[energy_key]
+            ])
             if "kinetic_energies" in self.vp_new.vasprun_dict.keys():
                 log_dict["energy_pot"] = (
                     log_dict["energy_tot"]
@@ -2092,7 +2113,15 @@ def collect(self, directory=os.getcwd(), sorted_indices=None):
             # log_dict = self.outcar.parse_dict.copy()
             if len(self.outcar.parse_dict["energies"]) == 0:
                 raise VaspCollectError("Error in parsing OUTCAR")
-            log_dict["energy_tot"] = self.outcar.parse_dict["energies"]
+            if self._energy_kind is None:
+                self._energy_kind = DftEnergyKind.ENERGY_FREE
+            OUTCAR_ENERGY_KIND_KEYS = {
+                    DftEnergyKind.ENERGY_FREE: "energies",
+                    DftEnergyKind.ENERGY_INTERNAL: "energies_int",
+                    DftEnergyKind.ENERGY_ZERO: "energies_zero",
+            }
+            energy_key = OUTCAR_ENERGY_KIND_KEYS[self._energy_kind]
+            log_dict["energy_tot"] = self.outcar.parse_dict[energy_key]
             log_dict["temperature"] = self.outcar.parse_dict["temperatures"]
             log_dict["stresses"] = self.outcar.parse_dict["stresses"]
             log_dict["pressures"] = self.outcar.parse_dict["pressures"]