[Nexus] proposed additions to NXdata for non-linear scaling - to aid cbf interoperability

[Mark Koennecke]

Hi,


On 02/19/2014 11:15 AM, Wintersberger, Eugen wrote:
> Hi folks
>
> On Wed, 2014-02-19 at 10:11 +0100, Benjamin Watts wrote:
>> Hi Jonathan,
>>      This kind of thing has been discussed at previous NIAC meetings.
>> Your proposal makes for a simple change, but does more to push the
>> problem further away from yourself than to actually solve it.
> If I understand Ben correctly what he means is that the code working
> with the stored data needs to do a lot of work to interpret it
> correctly.
>
>> What we
>> really need is some "standard" way to present mathematical formulae in
>> general that is accessible across different programming languages.
> That's the right way to go.
>
>> I
>> think maybe Eugen Wintersberger had a good suggestion, but I don't
>> recall any follow-up on it.
> Hm - I cannot recall that I made a good suggestion on this. However,
> what I would mot probably do is to use Python syntax to represent math.
> This has two advantages:
>
> 1.) an actual language can immediately execute the code
> 2.) it might be easy to write a parser for Python code in any other
> language.
>
> In my opinion 2. is the the critical point. Once you start with this you
> are basically inventing a new scripting language. Consequently, a
> program which wants to use the data needs to parse this code and takes
> the appropriate action which is not a trivial task.
>
> In addition one should be very careful with such things to not open
> Pandoras box. I would restrict this to plain math (no loops, no
> branching, etc.). Otherwise you really invent a new language.
>
> What is still open is how to fill the namespace for the code to execute.
> Where should all the data mentioned in
>
> offset  + data**c
>
> come from?
>
> At the end of the day there is one question we should seriously discuss:
> how far do we want to go with math in Nexus?
This is exactly the point why we never got down to anything in this.
In 2011, Amando was tasked to make a proposal but nothing ever
came from it. With the manpower and support we do not have, we
cannot support our own data interpreter, cross platform and good
performance wise.

IMHO, the wisest solution seems to be to add what is
absolutely required. Required in the sense to cover the use case where
you do not have the time to do the conversion on the fly before
writing the data to disk.

Regards,

             Mark





> regards
>    Eugen
>
>
>
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