Hi Togo, Yes, I meant non-primitive translation. For now I would prefer to retrieve this information from Spglib to avoid replication errors. I can have Avogadro translate a Hall symbol to the Hall number used in spg_database.c.
Dealing with International symbols and non-primitive unit cells could be troublesome, but I could always just force the user to choose an origin. Thanks, Albert On Aug 20, 2014, at 7:57 PM, Atsushi Togo <atz.t...@gmail.com> wrote: > Hi, > > If you mean origin_shift as non primitive translation part of space > group operations, I can understand what you wrote. I can extend spglib > so that the database is accessed from the API. The other option is > just to hard code the database in Avogadro's crystallography extension > itself. It may be a matter of strategy. If Avogadro may have a chance > to use other crystal symmetry libraries in the future, it may be > better the later option. > > Togo > > On Thu, Aug 21, 2014 at 6:06 AM, Defusco III, Albert A <defu...@pitt.edu> > wrote: >> Good afternoon everyone, >> >> I am working on getting porting the crystallography extension and space >> group support into Avogadro 2. What is missing from Avogadro 2 is a look-up >> of rotation matrices and origin shift vectors for a given space group. Do >> you believe it is possible to extend Sgplib so that I can get these >> quantities when specifying just the space group (either Hall symbol/number >> or international symbol/number)? >> >> >> Here's what I've done so far >> >> 1. I have added support for rotation matrices and origin shift vectors in >> Avogado2's UnitCell class and added a fillUnitCell method to >> crystaltools.cpp. A filled unit cell can then be given the the Spglib >> routines for further action. (The rotation matrices and origin shift vectors >> are only available if read from a cml file where they have been specified in >> <transform3> child nodes of <symmetry>.) >> >> 2. Once a filled unit cell is generated all AvoSpglib/Spglib routines are >> nearly unchanged when ported into Avogadro2. >> >> >> >> Here's an example of what I mean. >> >> int numRotations = get_rotation(int HallNumber, >> int rotation[][3][3], >> double origin_shift[][3]) >> >> HallNumber is read as input and rotation and origin_shift are populated on >> output.The length of the rotation and origin_shift arrays is numRotations. >> >> Using the space group "F 4d 2 3 -1d" (#525) there are 192 rotation matrices >> and origin shift vectors. >> >> >> >> Thanks, >> Albert >> >> >> >> >> ------------------------------------------------------ >> Albert DeFusco, Ph.D. >> Research Assistant Professor >> Technical Director, Center for Simulation and Modeling >> University of Pittsburgh >> Pittsburgh, PA 15260 >> 412-648-3094 >> http://www.sam.pitt.edu >> > > > > -- > Atsushi Togo > http://atztogo.github.com/ > atz.t...@gmail.com ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _______________________________________________ Avogadro-devel mailing list Avogadro-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/avogadro-devel
