Re: [h5md-user] Species Data Type

[Felix Höfling]

Am 20.08.2013, 22:54 Uhr, schrieb Pierre de Buyl  
<address@hidden>:

> Hi all,
>
> Peter Colberg <address@hidden> a écrit :
>
> > Hi Nicolas,
> >
> > On Tue, Aug 06, 2013 at 08:58:51PM +0200, Nicolas Höft wrote:
> > > Is it possible to read/write an enum type as int type? What I mean
> > > is: Is this backwards-compatible? Can a program that does not know
> > > about HDF5 enums simply read the int's and continue as usual?
> > >
> > > I really like the solution, though :-)
> >
> > It is compatible with readers expecting an integer data type. An
> > enumerated-type dataset can be read using, e.g., H5T_NATIVE_INT as
> > the memory datatype.
> >
> > For writing, however, the memory datatype needs to be an enumerated
> > type. A program extending an existing enumerated-type dataset needs
> > to be aware of this.
>
> Enums seem a very elegant solution. However, nothing prevents their
> use in the specification and the change would be backward compatible
> in the future.
>
> Suggesting their use would fit in the implementation appendix very
> well (see http://nongnu.org/h5md/implementation.html ).
>
> Cheers,
>
> Pierre

The implementation section is very helpful (I didn't notice it before).  
Thanks Peter for setting it up! Indeed, it would be the right place to  
discuss/demonstrate the use of enums.

Independent of that, we could add a brief note to the specification  
section pointing at the advantages of enums for systems with many particle  
species.

Felix