sPHENIX MAPS tracker discussion

[Martin Purschke <purschke AT bnl.gov>]

Hi Ming, all,

nice summary.

Just out of curiosity, I'm wondering why, under the "cheatsheet felix
rcdaq", so much emphasis is placed on getting at the last event?

> get last event number:
> dlist ../beamtest2018/calib/calib_00000708-0000.prdf -n 0 -i |tail
> 
> display last event (use last event number from above command):
> ddump ../beamtest2018/calib/calib_00000708-0000.prdf -n 10 -e 47892 -g|less
> 
> count events:
> dlist ../beamtest2018/calib/calib_00000708-0000.prdf -n 0|wc
> 

There is hardly a situation I could imagine where this is a required, or
even useful, information that rcdaq doesn't give you already? I mean,
all of those are *really* expensive commands, as you are parsing the
entire file just to get at a number.

I'm triggering on those kind of things because an early PHENIX
production manager repeatedly brought the RCF down to its knees by doing
something along those lines - he didn't know better and thought that the
processing macro would need the number of events up front.

BTW, the easiest and cheapest (but still expensive) way is

 dpipe -s f -d n -i file_name | wc -l

(that also counts special events). You "pipe" the events from a file (-s
f) to "nowhere" ( -d n), identifying each event as you go (-i), and then
count lines. No decoding, although you still read the entire file.

Some deeper info at

https://www.phenix.bnl.gov/~phoncs/oncs/code_documentation/Event/index.html

and

https://www.phenix.bnl.gov/~phoncs/oncs/code_documentation/Event/dlistddumpanddpipe.html

Best,
        Martin


On 5/19/19 19:41, Ming Liu wrote:
> Hi all,
> 
>  
> 
> Here is the web site for MVTX test beam activity website,
> 
> https://p25ext.lanl.gov/maps/beamtest_2019/index.html
> 
>  
> 
> Beam is expected tomorrow morning 8:00AM, and we are ready.  
> 
>  
> 
> Cheers,
> 
> Ming 
> 
> 
> _______________________________________________
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> 


-- 
Martin L. Purschke, Ph.D.        ;   purschke AT bnl.gov
                                 ;   http://www.phenix.bnl.gov/~purschke
                                 ;
Brookhaven National Laboratory   ;   phone: +1-631-344-5244
Physics Department Bldg 510 C    ;   fax:   +1-631-344-3253
Upton, NY 11973-5000             ;   skype: mpurschke
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