Convert supercell CLI option to tuple

docs/source/user_guide/command_line.rst

@@ -314,7 +314,7 @@ Calculate phonons with a 2x2x2 supercell, after geometry optimization (using the
 
 .. code-block:: bash
 
-    janus phonons --struct tests/data/NaCl.cif --supercell 2x2x2 --minimize --arch mace_mp --model-path small
+    janus phonons --struct tests/data/NaCl.cif --supercell 2 2 2 --minimize --arch mace_mp --model-path small
 
 
 This will save the Phonopy parameters, including displacements and force constants, to ``NaCl-phonopy.yml`` and ``NaCl-force_constants.hdf5``,
@@ -324,7 +324,7 @@ Additionally, the ``--bands`` option can be added to calculate the band structur
 
 .. code-block:: bash
 
-    janus phonons --struct tests/data/NaCl.cif --supercell 2x2x2 --minimize --arch mace_mp --model-path small --bands
+    janus phonons --struct tests/data/NaCl.cif --supercell 2 2 2 --minimize --arch mace_mp --model-path small --bands
 
 
 If you need eigenvectors and group velocities written, add the ``--write-full`` option. This will generate a much larger file, but can be used to visualise phonon modes.
@@ -333,7 +333,7 @@ Further calculations, including thermal properties, DOS, and PDOS, can also be c
 
 .. code-block:: bash
 
-    janus phonons --struct tests/data/NaCl.cif --supercell 2x3x4 --dos --pdos --thermal --temp-start 0 --temp-end 300 --temp-step 50
+    janus phonons --struct tests/data/NaCl.cif --supercell 2 3 4 --dos --pdos --thermal --temp-start 0 --temp-end 300 --temp-step 50
 
 
 This will create additional output files: ``NaCl-thermal.dat`` for the thermal properties (heat capacity, entropy, and free energy)

janus_core/cli/phonons.py

@@ -40,8 +40,8 @@ def phonons(
     ctx: Context,
     struct: StructPath,
     supercell: Annotated[
-        str, Option(help="Supercell lattice vectors in the form '1x2x3'.")
-    ] = "2x2x2",
+        tuple[int, int, int], Option(help="Supercell lattice vectors.")
+    ] = (2, 2, 2),
     displacement: Annotated[
         float, Option(help="Displacement for force constants calculation, in A.")
     ] = 0.01,
@@ -122,9 +122,8 @@ def phonons(
         Typer (Click) Context. Automatically set.
     struct : Path
         Path of structure to simulate.
-    supercell : str
-        Supercell lattice vectors. Must be passed in the form '1x2x3'. Default is
-        2x2x2.
+    supercell : tuple[int, int, int]
+        Supercell lattice vectors. Default is (2, 2, 2).
     displacement : float
         Displacement for force constants calculation, in A. Default is 0.01.
     mesh : tuple[int, int, int]
@@ -200,17 +199,6 @@ def phonons(
         raise ValueError("'fmax' must be passed through the --fmax option")
     minimize_kwargs["fmax"] = fmax
 
-    try:
-        supercell = [int(x) for x in supercell.split("x")]
-    except ValueError as exc:
-        raise ValueError(
-            "Please pass lattice vectors as integers in the form 1x2x3"
-        ) from exc
-
-    # Validate supercell list
-    if len(supercell) != 3:
-        raise ValueError("Please pass three lattice vectors in the form 1x2x3")
-
     calcs = []
     if bands:
         calcs.append("bands")