Re: updated geometry

[Beni Zihlmann <zihlmann@jlab.org>]

Hi Mark and All,
I guess one reason for the current handling is that in this way you do 
not need to have XERCES and XALAN installed
if you want just to run the MC. However if we would have all the 
necessary scripts at hand that would do a full blown installation
of all the software including the third party once that is needed to do 
the job then I think it would be a good idea to follow your
proposal.
Most people will never work with the geometry file or the data structure 
of the monte carlo and hence would not need
XERCES and XALAN. This will be even more true in the future. However a 
consistent software packaged in the full
sence is probably also more safe in terms of consistency to avoid any 
confusion about the results of different MC data
that has been generated by different people.  This aspect will be very 
crucial in the future when MC data productions
are needed to extract physics results from the real data.
Taking the long term future into account I think we should follow your 
proposal.

cheers,
Beni



Mark M. Ito wrote:
> Beni,
>
> Thanks for getting that done. Sounds like real progress.
>
> This brings up a code management issue that I have been wondering 
> about for some time. It seems like we have a two step process: 
> check-in new xml-based geometry information, then, by hand, generate 
> the corresponding Fortran GEANT code, then check in the fortran code. 
> This procedure violates the usual philosophy of only checking in 
> "source" materials and allowing a make system to generate "derived" 
> materials. It seems to have lead to some confusion about what we have 
> in the Monte Carlo vs. what we have in the geometry. And I suspect 
> some of the build problems I have had recently have to do with trying 
> to maintain both "source" and "derived" in the Subversion repository.
>
> My naive proposal is that we remove the Fortran GEANT code from the 
> repository and regenerate it as part of the make system. Then one is 
> guaranteed consistency between geometry specification and code. Also 
> (if this can be done) a user can modify the geometry and use it 
> immediately in the Monte Carlo without having to know the details of 
> how to generate the Fortran code, i. e., play with a private version 
> of the geometry without becoming an expert. Is there some fundamental 
> problem with this? Too computationally expensive? Too many "helper" 
> applications to install? Also, I have no idea how complicated it is to 
> generate the Fortran code given you have everything you need installed.
>
> On the subject of helper applications, I think we should be able to 
> put together enough documentation and scripts to install them on most 
> systems, especially if the applications are coming to us from 
> experienced/professional programmers.
>
> What do you and others think?
>
>  -- Mark
>
> Beni Zihlmann wrote:
>> Dear colleagues,
>> I updated the geometry in the repository. The geometry now reflects
>> all the changes and design decisions that have been made lately.
>> 1) remove outer most CDC layer thereby reducing the CDC radius by 1.6 cm
>>    including the cable runs.
>> 2) re-route the FDC cables to run upstream
>> 3) add an 8mm aluminum plate on the inside of the BCAL
>> 4) the BCAL readout segmentation is 4x6 (sector x layer)
>>
>> all these changes are now available the in geometry file hddsGeant3.F 
>> located in
>> src/programs/Simulation/HDGeant/
>>
>> cheers,
>> Beni
>>


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