Hi Nat,

The math is lost on me, but is it possible that revision 15658 solves the problem (in part or in whole)?

http://cctbx.svn.sourceforge.net/viewvc/cctbx/trunk/cctbx/sgtbx/space_group.cpp?r1=15082&r2=15658&sortby=rev

It should indeed but it is an ugly hack. I mean, using exceptions to implement the logic normally expressed with "if ... then" ...
So I stand by the opinion expressed above.

Luc