Using spg_get_spacegroup_type_from_symmetry fails to find the correct spacegroup for orthorhombic F ( Fdd2) when the primitive lattice vectors are expressed in a non-standard basis. To get this non-standard basis, the lattice vectors have been transformed by the matrix
(1,0,0)(-1,1,0)(-1,-1,1).
The attached example code demonstrates this, returning "C2" for the alternate setting while giving the correct "Fdd2" for the conventional primitive basis. I tried to figure out what is failing, but I'm afraid the complexities of spglib's search strategy defeated my attempts. I might guess that it has something to do with the rotations containing entries of "2" even though the transformation is volume-preserving.
On the other hand spg_get_dataset succeeds in both the conventional primitive and alternate basis. The test set is based on structure 1509692 in the crystallography open database.
test-spg-get-type.c.gz
Ag2O3-1509692-alt.cif.gz
Ag2O3-1509692.cif.gz
Using
spg_get_spacegroup_type_from_symmetryfails to find the correct spacegroup for orthorhombic F ( Fdd2) when the primitive lattice vectors are expressed in a non-standard basis. To get this non-standard basis, the lattice vectors have been transformed by the matrix(1,0,0)(-1,1,0)(-1,-1,1).The attached example code demonstrates this, returning "C2" for the alternate setting while giving the correct "Fdd2" for the conventional primitive basis. I tried to figure out what is failing, but I'm afraid the complexities of spglib's search strategy defeated my attempts. I might guess that it has something to do with the rotations containing entries of "2" even though the transformation is volume-preserving.
On the other hand
spg_get_datasetsucceeds in both the conventional primitive and alternate basis. The test set is based on structure 1509692 in the crystallography open database.test-spg-get-type.c.gz
Ag2O3-1509692-alt.cif.gz
Ag2O3-1509692.cif.gz