[sdpd] Re: Re-using software pieces

[Jon Wright <jpw22... @cus.cam.ac.uk>]

> If a good subroutine is able to translate the space group
> Hermann Mauguin notation into symmetry operators, it should
> be in the source code bank, clearly.

There's a routine in 'C' on Larry Finger's mirrored site at ccp14 which
purports to do just this.

/ccp14/ftp-mirror/larryfinger/symmtry.c

/* routine to interpret Hermann-Mauguin Space Group Symbol --
   Program adapted from a routine supplied by Prof. Burzlaff, Univ.
   Erlangen, Germany.  This version obtained from the LAZY-PULVERIX
   source code in FORTRAN and converted to C by L.W. Finger, 19-Apr-1992
*/ 

I haven't tried it.  I was recently disappointed with the routine in
GSAS which is supposed to do this job. GSAS chokes on "F 1 -3 2/m", a face
centred rhomohedral cell. 

Personally I've gotten to like the CCSL method of specifying generators.
It's unambiguous and lets you have whatever perverse setting you like (see
above).

Best,

Jon