Re: [h5md-user] Finalization of units module

[Pierre de Buyl]

On Thu, Dec 19, 2013 at 05:08:49PM +0100, Felix Höfling wrote:
> 
> The collision between hour and Planck's constant is really unfortunate. I
> copied the latter from Mosaic, but I'm not aware of an immediate
> application in semi-classical MD simulations. So way may drop it. BTW, wth
> sufficient knowledge about physical dimensions, the two symbols can not
> really be confused---but this can't be expected from automated parsing as
> in udunits.
> 
> Having "erg" but "dyne" out is a bit inconsistent, I would blame udunits
> for this. Dalton and Poise are frequently encountered in scientific
> literature, to specify polymer weights and fluid viscosities,
> respectively. Anyway, for version 1.0 we may blindly follow udunits and
> drop them too if it helps.
> 
> For the "degree" issue: I found "degC" in the XML file. We may equally use
> the longer form or use the extended ASCII character °, both are listed in
> udunits2.

Actually, an idea would be to use udunits2 without the data from
udunits2-common.xml that includes completely irrelevant (for us) units such as
"bps" of confusing units such as "cc" (cm+3).

The result would be a comprehensive combination of SI units and commonly used
units ("eV" for instance).

Reducing the set is useful also to avoid backwards compatibility problems.
However, to allows for domain specific uses, it would be good to add an
attribute "system", of simple scalar dataspace and of VL string datatype, to be
complete :-), the value being "SI" for the current set.

P