On Thursday 06 of February 2014 11:15:42 Atsushi Togo wrote:
> Dear Jure,
> 
> A) OK. Thanks.
> B) I'm fine to make a spglib interface to access the database. I will
> work on that. Then, even if you have database, the design of GUI would
> be e not easy. At least the designer should know the basic of
> crystallography, then you have to very restrict the possible inputs of
> lattice parameters and atomic positions to the standard settings. Most
> users don't know those crystallographic standard, so if you offer too
> much freedoms to users, you may get a lot of  questions from those
> users. If you ignore crystallographic definitions and conventions, the
> computer program breaks down mathematically.

I agree completely. But, IMHO as a beginner, having buttons to push and see 
what happens is the best way to learn. But there is no rush, fixing bugs is 
more important. For now, I wish simply to allow the user to choose the 
spacegroup using the Hall symbol, which is better than the current Set 
Spacegroup dialog. Is it OK with you if I use spgdb_get_spacegroup_type() 
directly to get the list of Hall symbols?

> C) My English skill is not enough to understand that you wrote. Hall
> symbol proposes possible sets of symmetry operations with respect to
> the choices of standard origins and axes. What I meant was, for
> example No. 5 shown below, that there are 9 different ways to
> represent it and you can recover 9 different sets of symmetry
> operations from those Hall symbols following information of tables in
> http://cci.lbl.gov/sginfo/hall_symbols.html , i.e. Hall symbols are
> very condensed way to represent matrix representations, and those
> tables are just necessary to recover the matrix representations
> following the recipe but not to generate the matrix representations by
> multiplying all the information in the tables. But for P1, there is
> only one.
> 
>      5:b1     C 1 2 1        C 2y
>      5:b2     A 1 2 1        A 2y
>      5:b3     I 1 2 1        I 2y
>      5:c1     A 1 1 2        A 2
>      5:c2     B 1 1 2        B 2
>      5:c3     I 1 1 2        I 2
>      5:a1     B 2 1 1        B 2x
>      5:a2     C 2 1 1        C 2x
>      5:a3     I 2 1 1        I 2x

Thank you for clarifying.

Regards,

Jure


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