[Rivet] Hepdata numbering

[Graeme Watt]

Dear All,

This was a conscious decision to improve the YODA export of 
multidimensional tables, so that we now write the appropriate YODA 
object for the number of independent variables, rather than always a 
Scatter2D object:

https://github.com/HEPData/hepdata-converter/issues/5#issuecomment-135375309

I checked with Andy that he agreed with this decision (in an email sent 
on 27th August 2015).

Most (or even all?) existing HepData tables exported as YODA for use in 
Rivet analyses will only have one independent variable and one dependent 
variable (x01-y01).  I suspect that Rivet analyses containing path names 
with something different were prepared independently from the 
corresponding HepData record and so the path names don't match anyway 
(even on the old HepData site).  Please let me know if you're aware of 
any existing Rivet analyses with path names containing something 
different than "x01" that correspond to a HepData table with more than 
one independent variable.  These are the only cases that would be 
affected by the change, and I'm not aware of any so far (and neither was 
Andy when I asked him back in 2015).

It's been requested in the past to allow an option in the HepData input 
file to allow some override of the automatic path names, but I think it 
would be better to allow some kind of "mapping" to be coded within the 
Rivet analysis between the HepData histogram names and the Rivet 
histogram names, for cases where they don't match.  Andy made some 
comments on this last week: 
https://www.hepforge.org/lists-archive/rivet/2017-February/007602.html

Best regards,
Graeme Watt (HEPData)



On 16/02/17 11:15, David Grellscheid wrote:
> Hi Graeme,
>
> do I understand correctly that the new Hepdata engine has changed the
> numbering on existing archived datasets and not just the new ones coming in?
>
> Thanks,
>
>   David
>
>
>
>
> On 16/02/2017 10:59, Christian Gutschow wrote:
>> Dear Graeme,
>>
>> thanks for your quick reply. Yes exactly, four 1-D histograms with varying x and y path fields is what I’m after. I suppose I can work around that for this analysis, but as ATLAS Rivet contact I can already see this seemingly minor feature cause an awful lot of frustration elsewhere.
>>
>> There are already many Rivet analyses relying on path names containing not just the "x01" that would need changing and I’m not sure this is a path we wanna head down to be honest. On the experiment side, we have elaborate MC validation frameworks that make use of Rivet analyses and their existing path names, so I’m worried that changes to the now well-established naming scheme will cause havoc all over the place…
>>
>> In fact, what will happen when (not if) we sync the Rivet reference data repository against HEPData? I’m fairly sure this will break everything and we’ll receive lots of abuse...
>>
>> I’m cc’ing the Rivet list as I think the Rivet developers (and users) need to be aware of this and this needs to be discussed. I wonder whether a comprise is feasible where we just add an additional 'qualifier' field to the YAML input, that would allow us to set the d01-x01-y01 style YODA names?
>>
>> Cheers,
>> Chris
>>
>>
>> On 16 Feb 2017, at 10:17, Graeme Watt <Graeme.Watt at durham.ac.uk<mailto:Graeme.Watt at durham.ac.uk>> wrote:
>>
>> Dear Chris,
>>
>> Good question.  On the old HepData site, a data table could be defined as "*data: x : x : y : y" (in the oldhepdata format, corresponding to two independent variables and two dependent variables), giving the YODA path names you mention, i.e. four 1-D histograms: y1(x1), y2(x1), y1(x2), y2(x2), written as Scatter2D objects.  But an alternative interpretation of such a table might be two 2-D histograms, y1(x1,x2) and y2(x1,x2).  To remove the ambiguity, we use only the latter interpretation on the new HEPData site, writing two Scatter3D objects with path names d01-x01-y01 and d01-x01-y02.
>>
>> Since I think you want four 1-D histograms rather than two 2-D histograms, you need to define two different tables, each with one independent variable and two dependent variables, giving YODA path names:
>> d01-x01-y01
>> d01-x01-y02
>> d02-x01-y01
>> d02-x01-y02
>> So the new HEPData site will always define YODA path names with "x01" and it is not possible to get the path names mentioned in your email.  I hope this is not a problem for you, but you might need to modify the path names in an existing Rivet analysis.
>>
>> Best regards,
>> Graeme
>>
>>
>> On 15/02/17 23:34, Christian Gutschow wrote:
>> Hi,
>>
>> I’m trying to work out how to write a YAML input file that will be interpreted as table with 2 different independent variables, each with two dependent variables. In YODA language the idea would be something like:
>>
>> d01-x01-y01
>> d01-x01-y02
>> d01-x02-y01
>> d01-x02-y02
>>
>> I’d already be happy if perhaps you could point me to an example entry where this has been achieved, so I can take a look at the corresponding YAML file.
>>
>> Many thanks in advance!
>>
>> Cheers,
>> Chris
>>
>>
>>   —
>>
>>   Dr. Christian Gütschow
>>
>>   Department of Physics and Astronomy
>>   University College London
>>   Gower Street
>>   London WC1E 6BT
>>
>>   > D10 Physics Building
>>   > +44 (0)20 7679 3775
>>   > chris.g at cern.ch<mailto:chris.g at cern.ch>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>   —
>>
>>   Dr. Christian Gütschow
>>
>>   Department of Physics and Astronomy
>>   University College London
>>   Gower Street
>>   London WC1E 6BT
>>
>>   > D10 Physics Building
>>   > +44 (0)20 7679 3775
>>   > chris.g at cern.ch<mailto:chris.g at cern.ch>
>>
>>
>>
>>
>>
>>
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