[Halld-offline] reducing file sizes

[Blake Leverington]

Hi guys,

This is just sort of a general query. I'm looking at different ways of 
reducing file size and cpu times for a rather large PYTHIA data 
set(2.5x10^8) events. Aside from simply filtering out events I was 
hoping I could cut out some of the information that HDGEANT records 
since I am only using information from the calorimeters. The rest of the 
detectors are effectively dead material for my analysis. Any thoughts on 
whether this is feasable, possible or just plain ineffective in reducing 
my file size?

Cheers,
-Blake

David Lawrence wrote:
>
> Hi Pawel,
>
>     I'm CC-ing the HallD-Offline mailing list since this may be of 
> general interest.
>
>     Yes, you can use janaroot with auto_activate. In order to get 
> anything useful, you will either need to run mcsmear on your 
> hdgeant-produced hddm file, or tell JANA to use the TRUTH hits in 
> reconstruction (which will give unrealistically good results). To do 
> the former, do this:
>
> 1.) edit control.in and run hdgeant to produce hdgeant.hddm file
>
>     > hdgeant
>
>
> 2.) run mcsmear on the hdgeant.hddm file to get file with smeared 
> values called hdgeant_smeared.hddm. (Passing the -n command line 
> switch prevents generation of random hits.)
>
>     > mcsmear -n hdgeant.hddm
>
>
> 3.) run hd_ana with the janaroot plugin and appropriate auto_activate 
> switch to get your ROOT file. For example:
>
>     > hd_ana -PPLUGINS=janaroot,janadot --auto_activate=DFCALPhoton 
> hdgeant_smeared.hddm
>
> Note that here, I used the alternate way of specifying plugins that 
> makes it a little more compact when specifying more than one plugin. I 
> added the janadot plugin just for fun so I could make a picture of the 
> call graph used. I've attached it here for the current example:
>
>
>
>
> Regards,
> -David
>
> pawel at jlab.org wrote:
>>  Hi David,
>>
>>   
>>> This modification was done by Brad and Ryan and checked in some time
>>> ago.  I think you should have seen this when you moved the simulation
>>> of FCAL response from the FCAL library into mcsmear.  I'm cc'ing both
>>> of them -- maybe they can comment.
>>>     
>>
>>  In Matt's message above he mentions moving of the FCAl response
>>  into mcsmear. I wanted to ask you about that earlier but got distracted.
>>  How do I retrieve the FCAL information from an hddm file?
>>  I can't use the auto_activate mechanism in conjunction with janaroot plugin, can I?
>>
>>  Thanks for any help,
>>  Pawel
>>
>>
>>
>>   
>
> -- 
>
> ------------------------------------------------------------------------
>  David Lawrence Ph.D.
>  Staff Scientist                 Office: (757)269-5567   [[[  [   [ [       
>  Jefferson Lab                   Pager:  (757)584-5567   [  [ [ [ [ [   
>  http://www.jlab.org/~davidl     davidl at jlab.org         [[[  [[ [[ [[[
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