GlueX Software Meeting

[David Lawrence <davidl@jlab.org>]

Hi All,

   Here's a reminder about Today's Hall-D Software meeting at 15:30 EST. 
You can connect by phone (see instructions below), or come by CC L207 if 
you're on site.

The web page for the meeting is on the wiki at:

http://www.jlab.org/Hall-D/software/wiki/index.php/January_8%2C_2007_Software

Agenda:

This will be a brief meeting so we can discuss where we are in so far as 
the schedule for
CD-2 and plan out our next couple of meetings.



To connect by telephone:
1.) dial:
 800-377-8846 : US
 888-276-7715 : Canada
 302-709-8424 : International

2.) enter participant code: 39527048#  (remember the "#")


See you there,
-David


Minutes from the last software meeting :

==Agenda==

# Review minutes from [[December 11, 2006 Software]] meeting
# [[Background Rate Studies]] (Matt)
# Charged particle tracking 
[http://www.jlab.org/~davidl/HallD/Presentations/2006_12_18 slides] (David)
# Code documentation update (Elliott) 
[http://www.codeassets.com/doc_tools.htm CodeAssets] 
[http://dmoz.org/Computers/Programming/Development_Tools/Documentation 
dmoz] 
[http://freshmeat.net/search/?q=source+code+documentation&trove_cat_id=847&section=trove_cat&Go.x=0&Go.y=0 
freshmeat]
# Make alternatives (Elliott) 
[http://dmoz.org/Computers/Software/Build_Management/desc.html dmoz] 
[http://directory.fsf.org/devel/build/ FSF] 
[http://freshmeat.net/articles/view/1715/ freshmeat] 
[http://www.google.com/Top/Computers/Software/Build_Management/Resources/ 
google]
# Boost library intro (Elliott) [http://www.boost.org/ Boost.org] 
[http://www.boost.org/libs/smart_ptr/smart_ptr.htm shared_ptr<>]

==Minutes==

Attendees: Elke A., Mark I., David L.(chair), Elliott W., Simon T.,  ON 
THE PHONE: Richard J., Matt S., Mihajlo K.

===Review of last week's minutes===
There was a discussion of Mihajlo's presentation at last week's meeting 
on the FCAL reconstruction.
The FCAL reconstruction code was adapted from the Rad-&phi; code of 
which, Richard was one of the
original authors. The "blind spot" phenomenon experienced in Rad-&phi; 
due to total internal reflection
at the back of the lead-glass blocks was discussed. The reconstruction 
code accomodates this and the
Indiana group were planning on modeling it in HDGeant. Richard pointed 
out that the blind spot was
due to the way the PMT was coupled to the block (air-gap) and GlueX will 
be able to avoid this problem
with a better coupling scheme.

There was also discussion about inserting a non-linearity into the 
detector response modeled in HDGeant
for the FCAL blocks due to shower depth. Currently, the response is 
directly proportional to energy loss.

===Background Rate Studies===
Matt showed some initial results from the EM background rate Monte Carlo 
studies he's doing for GlueX.
He used the built-in coherent bremstrahlung generator and just threw 
massive numbers of events and then
looked at the detector responses. Richard pointed out that a factor of 
125 is needed to scale rates up
to the true background rate since the built-in generator cuts out 
un-tagged photons (I recall there was
another condition, but can't remember it right now).

Some problems were noted in a few of the plots. Richard requested that 
the minutes make a note of finding
the bug in plot 1 where he saw an inconsistency.

Matt and Richard were going to talk offline.

===Charged Particle Tracking===
''deferred for lack of time''

===Source Code Documentation===
Elliott reported that he made a quick web survey of source code 
documentation schemes. The intent was
to make sure Doxygen was still active and commonly used. He found there 
are many options for
automatically generating documentation directly from C++ source code. 
However, he found no compelling
reason to switch from Doxygen at the moment.

===Make system alternatives===
Elliott reported on a quick survey he did on ''make'' systems. He found 
many people are dissatisfied with
GNU Make and numerous alternatives exist. There does not seem to be a 
single alternative emerging
as the true successor yet.

David remarked that some effort has already been put into our current 
gmake-based system(BMS). Incorporating
a new system will bring a cost in development with limited benefit 
potential.

No is planned at this time.

===Boost library===
Elliott gave a brief introduction to some features found in the BOOST 
library for C++. While we may not
wish to incorporate BOOST completely, one thing particular interest to 
us may be shared pointers.
This is a construct that essentially allows garbage collection in C++ 
similar to what the system provides
automatically in JAVA. The idea of the shared pointer is that it has an 
internal resource counter that
keeps track of how often it is copied so that when the last shared 
pointer object referring to a given object
goes out of scope, the object itself is deleted.

The group was tasked with trying to play with shared pointers some in 
simple example programs in
order to gain some experience on which to base further discussion.

==Action Items==
#Freezing tags in subversion through hooks (David)
#Put tarballs of external packages on Wiki(David)
#SVN web interface for browsing change logs (David)
#Design and implement exception and logging scheme for JANA
#Discuss integration issues
#Experiment with shared pointers

-- 

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  David Lawrence Ph.D.
  Staff Scientist                 Office: (757)269-5567   [[[  [   [ [       
  Jefferson Lab                   Pager:  (757)584-5567   [  [ [ [ [ [   
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