From f8587b28ec67100cc3de7638fba4b0aad4e91301 Mon Sep 17 00:00:00 2001
From: seshasaibehara <seshasaibehara@gmail.com>
Date: Thu, 26 Feb 2026 14:18:18 -0800
Subject: [PATCH 1/2] write magmoms in incar

---
 casm/tools/shared/ase_utils.py | 72 +++++++++++++++++++++++++++++++++-
 1 file changed, 70 insertions(+), 2 deletions(-)

diff --git a/casm/tools/shared/ase_utils.py b/casm/tools/shared/ase_utils.py
index a424625..762c34f 100644
--- a/casm/tools/shared/ase_utils.py
+++ b/casm/tools/shared/ase_utils.py
@@ -57,6 +57,58 @@ def make_ase_atoms(casm_structure: xtal.Structure) -> ase.Atoms:
     )
 
 
+def make_magnetic_ase_atoms(
+    casm_structure: xtal.Structure, magmom_dict: dict
+) -> ase.Atoms:
+    """Given a CASM Structure and magnetic moments to be used for each specific species,
+    convert it to an ASE Atoms. If a magnetic moment is not provided for a species, it is
+    set to 1.0
+
+    .. attention::
+
+        This method only works for atomic structures where magnetic moments are not explicit
+        degrees of freedom and are only added at the setup stage.
+        If the structure contains molecular information, an error will be raised.
+
+    Notes
+    -----
+
+    This method converts a CASM Structure object to an ASE Atoms object. It includes:
+
+    - the lattice vectors
+    - the atomic positions
+    - the atomic types
+
+    Parameters
+    ----------
+    casm_structure : libcasm.xtal.Structure
+    magmom_dict : dict
+
+    Returns
+    -------
+    ase.Atoms
+
+    """
+    if len(casm_structure.mol_type()):
+        raise ValueError(
+            "Error: only non-magnetic atomic structures may be converted using "
+            "to_ase_atoms"
+        )
+
+    symbols = casm_structure.atom_type()
+    positions = casm_structure.atom_coordinate_cart().transpose()
+    cell = casm_structure.lattice().column_vector_matrix().transpose()
+
+    magmoms = [
+        magmom_dict[symbol] if symbol in magmom_dict.keys() else 1.0
+        for symbol in symbols
+    ]
+
+    return ase.Atoms(
+        symbols=symbols, positions=positions, cell=cell, pbc=True, magmoms=magmoms
+    )
+
+
 def make_casm_structure(ase_atoms: ase.Atoms) -> xtal.Structure:
     """Given an ASE Atoms, convert it to a CASM Structure
 
@@ -351,11 +403,16 @@ def __init__(
         incar_path = None
         kpoints_path = None
         settings = {}
+        species_settings = {}
         if self.calctype_settings_dir is not None:
             settings = json_io.read_required(
                 path=self.calctype_settings_dir / "calc.json"
             )
 
+            species_settings = json_io.read_optional(
+                path=self.calctype_settings_dir / "species.json"
+            )
+
             incar_path = calctype_settings_dir / "INCAR"
             if not incar_path.exists():
                 incar_path = None
@@ -369,6 +426,8 @@ def __init__(
         calctype_settings_dir, which will be passed to the 
         :class:`ase.calculators.vasp.Vasp` calculator constructor."""
 
+        self.species_settings = species_settings
+
         self.incar_path = incar_path
         """Optional[pathlib.Path]: Path to the template INCAR file, if it exists."""
 
@@ -376,8 +435,11 @@ def __init__(
         """Optional[pathlib.Path]: Path to the template KPOINTS file, if it exists."""
 
         ### Functions to convert between CASM Structure and ASE Atoms
+        if "magmoms" in species_settings.keys():
+            self._make_ase_atoms_f = make_magnetic_ase_atoms
 
-        self._make_ase_atoms_f = make_ase_atoms_f
+        else:
+            self._make_ase_atoms_f = make_ase_atoms_f
         """Callable[[libcasm.xtal.Structure], ase.Atoms]: Function to convert CASM 
         Structure to ASE Atoms."""
 
@@ -447,7 +509,13 @@ def setup(
         vasp_calculator: ase.calculators.vasp.Vasp
             The ASE VASP calculator object.
         """
-        ase_atoms = self._make_ase_atoms_f(casm_structure)
+        if "magmoms" in self.species_settings.keys():
+            ase_atoms = self._make_ase_atoms_f(
+                casm_structure, magmom_dict=self.species_settings["magmoms"]
+            )
+
+        else:
+            ase_atoms = self._make_ase_atoms_f(casm_structure)
         vasp_calculator = self.make_calculator(ase_atoms=ase_atoms, calc_dir=calc_dir)
 
         # Write INCAR, KPOINTS, POTCAR, POSCAR

From 7fff735baac77962b03eb7c45ed9b42ede39b0e6 Mon Sep 17 00:00:00 2001
From: seshasaibehara <seshasaibehara@gmail.com>
Date: Thu, 26 Feb 2026 14:39:41 -0800
Subject: [PATCH 2/2] add empty species dict as default

---
 casm/tools/shared/ase_utils.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/casm/tools/shared/ase_utils.py b/casm/tools/shared/ase_utils.py
index 762c34f..36922b9 100644
--- a/casm/tools/shared/ase_utils.py
+++ b/casm/tools/shared/ase_utils.py
@@ -410,7 +410,7 @@ def __init__(
             )
 
             species_settings = json_io.read_optional(
-                path=self.calctype_settings_dir / "species.json"
+                path=self.calctype_settings_dir / "species.json", default={}
             )
 
             incar_path = calctype_settings_dir / "INCAR"