[Halld-offline] Minutes, GlueX Offline Software Meeting, Dec. 15, '10

[Mark M. Ito]

Find the minutes at 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Offline_Meeting%2C_December_15%2C_2010#Minutes 
and as text below.

============

GlueX Offline Meeting, December 15, 2010

Minutes

Present:
* IU: Kei Moriya, Matt Shepherd
* JLab: Craig Bookwalter, Mark Ito (chair), David Lawrence, Lubomir
Pentchev, Dmitry Romanov, Sascha Somov, Simon Taylor, Beni Zihlmann


Announcements

* Simon announced that he has added time and energy smearing to the
start counter in mcsmear.


Review of minutes from previous meeting

We went over the [35]minutes from the December 15th meeting.
* David mentioned yet another issue with using GEANT3 for our
simulation. There are some CERNLIB routines that we have imported
to the GlueX repository because of bug fixes. These can sometimes
cause problems with include files.


Tagger hall geometry/simulation

Sascha led us through some recent work he has done, documented in a
[37]recent GlueX Note. The main conclusion is that we expect that dark
rates in SiPM's used in the microscope could increase by a factor of
five in about 2.5 months. This estimate includes shielding with
polyethylene which reduces the exposure by about a factor of 7. See his
note for details.

The geometry configurations that were used have not been released for
public consumption yet. See Sascha if you have a need for them.

Calibration Database Update

Dmitry gave us a review of the scheme for the calibration database and
reported on the current status. See [39]his slides for details. Status
is as follows:
* File specification is done
* File upload to DB in progress
* “Field” C++ API in progress
* Core C++ API done
* User C++ API mostly done
* Python wrapping--mostly done
* Console utils--first working prototype is done
* Web interface--prototype is done

There was some discussion during and after the talk:
* Security: We had a lot of discussion about what level of security
was necessary or appropriate. Too little and unauthorized changes
can be made to sensitive calibration sets. Too much and making
modifications is made difficult and the central collaboration copy
might not get all important changes; those changes may languish in
private version.
* Access outside JLab firewall: Richard asked about how the constants
would be accessed outside JLab.
1. David has implemented a web service to deliver constants. This
was some time ago and needs to be revisited.
2. The database can be replicated at other sites and access
granted to the replicas as needed. This is useful for the
console tools, for example.
3. The system will export files that can be used to supply
constants from a local filesystem. For example, this could be
used on a laptop without a network connection.
4. [added in press] There will be a web application that will
allow users with a web browser to access the contents of the
database.


Random number seed policy

Richard reviewed the options he outlined in his [41]email to the
offline list. He recalled for us that the issue was raised by [42]Kei
getting indentical results from separate runs of genr8 when they were
started within a second of each other.

We formed a consensus around using /dev/urandom, at least initially. We
commissioned Richard to write an appropriate python script that would
produce a seed on standard output as an initial stab at a more robust
random seed strategy.

David noted that we should add better random seed management to
mcsmear.

New Action Items

1. Write a python script that uses /dev/urandom to produce pretty darn
random numbers.
2. Random seed management for mcsmear.
__________________________________________________________________

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References

35. 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Offline_Meeting%2C_December_15%2C_2010#Minutes
37. 
http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=1646
39. https://halldweb1.jlab.org/talks/2010-12/db_design_12_15_2010.pptx
41. 
https://mailman.jlab.org/pipermail/halld-offline/2010-December/000446.html
42. 
https://mailman.jlab.org/pipermail/halld-offline/2010-December/000443.html