Use self.info.spin to determine spin type for Mulliken charges

src/sisl/io/siesta/stdout.py

@@ -11,6 +11,7 @@
 from sisl._common import Opt
 from sisl._internal import set_module
 from sisl.messages import deprecation, warn
+from sisl.physics import Spin
 from sisl.unit.siesta import unit_convert
 from sisl.utils import PropertyDict
 from sisl.utils.cmd import *
@@ -34,6 +35,20 @@ def _ensure_atoms(atoms):
     return atoms
 
 
+def _parse_spin(attr, match):
+    spin_string = match.group(1)
+    if spin_string == "none":
+        return Spin.UNPOLARIZED
+    elif spin_string == "collinear":
+        return Spin.POLARIZED
+    elif spin_string == "non-collinear":
+        return Spin.NONCOLINEAR
+    elif "spin-orbit" in spin_string:
+        return Spin.SPINORBIT
+    else:
+        assert False  # Should never reach here
+
+
 @set_module("sisl.io.siesta")
 class stdoutSileSiesta(SileSiesta):
     """Output file from Siesta
@@ -48,6 +63,11 @@ class stdoutSileSiesta(SileSiesta):
             lambda attr, match: lambda: True,
             default=lambda: False,
         ),
+        _A(
+            "spin",
+            r".*Spin configuration\s*=\s*(\S+)\s*",
+            _parse_spin,
+        ),
     ]
 
     @deprecation(
@@ -1259,26 +1279,13 @@ def try_parse_int(s):
                         atom_charges.append(charge)
 
             # Determine with which spin type we are dealing
-            IDX_NON_POL = 0
-            IDX_POL = 1
-            IDX_NC = 2
-            search_keys_spin = [
-                "Qatom",  # if we find Qatom and no "mulliken: Spin UP" we are dealing with spin unpolarized
-                "mulliken: Spin UP",
-                "Svec",
-            ]
-            loc = self.fh.tell()
-            ret = self.step_to(
-                search_keys_spin, case=True, ret_index=True, allow_reread=False
-            )
-            self.fh.seek(loc)
-            if ret[2] == IDX_NON_POL:
+            if self.info.spin == Spin.UNPOLARIZED:
                 # No spin components so just parse charge
                 atom_charges = []
                 atom_idx = []
                 header = ["e"]
                 _parse_spin_pol()
-            elif ret[2] == IDX_POL:
+            elif self.info.spin == Spin.POLARIZED:
                 # Parse both spin polarizations
                 atom_charges_pol = []
                 header = ["e", "Sz"]
@@ -1294,7 +1301,7 @@ def try_parse_int(s):
                 atom_q = atom_charges_pol_array[0, :] + atom_charges_pol_array[1, :]
                 atom_s = atom_charges_pol_array[0, :] - atom_charges_pol_array[1, :]
                 atom_charges[:] = np.stack((atom_q, atom_s), axis=-1)
-            elif ret[2] == IDX_NC:
+            elif self.info.spin == Spin.NONCOLINEAR or self.info.spin == Spin.SPINORBIT:
                 # Parse as long as we find new species
                 atom_charges = []
                 atom_idx = []