Hi Emre,
We are trying to identify affine normalizers' space group from the additional operators, but having difficulties in introducing the arbitrary translations.
As an example, suppose that our "base" space group is 25, and the additional operators are: -x,-y,-z x+1/2,y,z x,y+1/2,z x,y,z+t
which, combined, defines P1 mmm
But we couldn't find a way to introduce "x,y,z+t" while we are "expand_smx"ing the space group with these operators.
The space_group class only supports finite groups (and only in settings that can be represented with integral rotation parts and rational translation parts). We have the class cctbx.sgtbx.search_symmetry, which multiplies the discrete origin shifts into the space group and keeps track of the continuous allowed origin shifts separately. It would need new code to determine a full description of affine normalizers. (Are they considered space groups?) Ralf