Added alternative method handling for xtb

ccinput/packages/xtb.py

@@ -1,7 +1,7 @@
 import os
 
 from ccinput.constants import CalcType, ATOMIC_NUMBER, LOWERCASE_ATOMIC_SYMBOLS
-from ccinput.utilities import get_solvent
+from ccinput.utilities import get_solvent, get_method
 from ccinput.exceptions import InvalidParameter, ImpossibleCalculation
 
 
@@ -17,6 +17,14 @@ class XtbCalculation:
         CalcType.CONSTR_CONF_SEARCH: "crest",
     }
 
+    GFN_KEYWORDS = {
+        "gfn2-xtb": "",
+        "gfn1-xtb": "--gfn 1 ",
+        "gfn0-xtb": "--gfn 0 ",
+        "gfn-ff": "--gfnff ",
+        "gfn2-xtb//gfn-ff": "--gfn2gfnff ",
+    }
+
     def __init__(self, calc):
         self.calc = calc
         self.program = ""
@@ -50,6 +58,17 @@ def get_output_name(self):
             return self.calc.name + ".xyz"
 
     def handle_parameters(self):
+        method = get_method(self.calc.parameters.method, "xtb")
+
+        if method not in self.GFN_KEYWORDS:
+            raise InvalidParameter(
+                f"Unknown method for xtb: {self.calc.parameters.method}"
+            )
+
+        method_keyword = self.GFN_KEYWORDS[method]
+        if method_keyword != "":
+            self.main_command += method_keyword
+
         if self.calc.parameters.solvent != "":
             if (
                 self.calc.parameters.solvation_radii != ""

ccinput/tests/test_xtb.py

@@ -697,6 +697,20 @@ def test_gfn1(self):
 
         self.assertTrue(self.is_equivalent(REF, xtb.command))
 
+    def test_gfn1_method(self):
+        params = {
+            "type": "Single-Point Energy",
+            "method": "gfn0",
+            "file": "ethanol.xyz",
+            "software": "xtb",
+        }
+
+        xtb = self.generate_calculation(**params)
+
+        REF = "xtb ethanol.xyz --gfn 0"
+
+        self.assertTrue(self.is_equivalent(REF, xtb.command))
+
     def test_gfn2(self):
         params = {
             "type": "Single-Point Energy",
@@ -725,6 +739,20 @@ def test_gfnff(self):
 
         self.assertTrue(self.is_equivalent(REF, xtb.command))
 
+    def test_gfnff_method(self):
+        params = {
+            "type": "Single-Point Energy",
+            "file": "ethanol.xyz",
+            "software": "xtb",
+            "method": "gfnff",
+        }
+
+        xtb = self.generate_calculation(**params)
+
+        REF = "xtb ethanol.xyz --gfnff"
+
+        self.assertTrue(self.is_equivalent(REF, xtb.command))
+
     def test_unavailable_calc_type(self):
         params = {
             "type": "TS Optimisation",

pyproject.toml

@@ -2,5 +2,6 @@
 requires = [
 	"setuptools>=42",
 	"wheel",
+    "versioneer-518",
 ]
 build-backend = "setuptools.build_meta"