GlueX Offline Meeting, February 9, 2011
GlueX Offline Software Meeting
Wednesday, February 9, 2011
1:30 pm EST
JLab: CEBAF Center F326/7
- 1 Agenda
- 2 Communication Information
- 3 Minutes
- New JANA release: David
- New sim-recon release: sim-recon-2011-02-02: Mark
- Review of minutes from the last meeting: all
- Review of Collaboration Meeting: all
- Reconstruction Parameters vs. Calibration Constants: Mark
- Compiler Warnings: Beni
- Calibration Database Update: Dmitry
- Timing Resolution: Kei
- Action Item Review: all
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- Review of recent repository activity: all
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Talks can be deposited in the directory
/group/halld/www/halldweb/html/talks/2011-1Q on the JLab CUE. This directory is accessible from the web at https://halldweb.jlab.org/talks/2011-1Q/ . You have to be a member of the "halld" Unix group to do this.
- CMU: Curtis Meyer
- IU: Ryan Mitchell, Kei Moriya
- JLab: Hovanes Egiyan, Mark Ito (chair), David Lawrence, Yi Qiang, Elton Smith, Simon Taylor, Elliott Wolin, Beni Zihlmann
- New JANA release. David is about to release a new version of JANA. It will include new features and bug fixes accumulated since the last release. He will give us more details at the next meeting.
- New sim-recon release: sim-recon-2011-02-02. Mark is preparing another release. The last one was at the end of November, so we are due.
Review of minutes from the last meeting
We went over minutes from the January 26 meeting.
David asked the Regina folks about the status of work on the BCAL reconstruction code. Both Andrei Semenov and Zisis Papandreou responded. Andrei and Irina Semenova are working on it. Their first code is to understand the present algorithm. Eugene Chudakov has commented that if there is a problem with split-off, we need to know about it sooner rather than later and Elton's understanding is that the current focus is on deciding the summing scheme in the BCAL rather than in suppressing extraneous showers. David will follow up on the split-off issue.
Collaboration Meeting Review
We discussed an item that came up at last week's collaboration meeting: the IT Review and our computing estimates. Simon has done some work estimating the time it takes to reconstruct bggen events with our current code. Mark is working on the estimates. He will circulate a version soon. There will be an IT Steering committee meeting Thursday to outline the topics to be addressed at the the review. Elton pointed out that we need a note on the estimate, explaining where the numbers come from and what assumptions were made. In particular, we need to revisit the issue of storing Monte Carlo generated data. If that data volume is comparable to (or exceeds) that of raw data then our computing model would have to be changed significantly.
Reconstruction Parameters vs. Calibration Constants
We had a discussion of how to manage reconstruction parameters versus calibration constants. An example of the former (parameters) would be the minimum number of hits in a charged track, an example of the latter (constants) would be the minimum drift time for those hits. Some parameters are currently stored in the calibration files (SVN: trunk/calib) and thus will migrate to the calibration database. Mark thought that they should be managed as configuration parameters to JANA, since different parameters might be used for different analysis of the same data and calibration constants had more of the character of "best for all occasions". Others thought that putting them in the database had the advantage of "everything in one place".
We did not come to a conclusion, but David agreed to give a talk on the JANA configuration scheme at a future meeting so we could have a more informed discussion.
Beni discussed his recent email pointing out that sim-recon gives warnings with the latest version of the GNU compilers. He has given Richard Jones an account on his machine so that Richard can have a look at the HDGRANT-related warnings. There are some warnings from the BCAL that should be looked at as well.
Using Profiling Tools to Guide Optimization
Dmitry walked us through a recent exercise he went through to speed up the CCDB code. He used profiling tools in two contexts: the C++ code and the MySQL server. Profiling the C++ code attemting to read a large volume of constants revealed that the bulk of the time was being taken in database queries. Subsequently, the MySQL profiling tool allowed him to identify an appropriate index to create in the database. He also implemented some pre-stored queries. This resulted in almost a factor of seven improvement in performance. He noted that using the tools allowed him to focus on improvements that really made a difference, not just on those that may sound good. See his slides for details.
Timing Resolution: Kei
Kei presented work on looking at timing resolution in the BCAL and TOF and how it affects particle identification. He found that using the "T0" that comes from tracking as a starting time degrades performance; one does better by leaving it out altogether. See his slides for details. T0 is a start counter time; the true starting time should come from picking out the correct RF bucket of the electron beam. David suggested that perhaps we should add a time to the DVertex class that could serve as a place-holder for this quantity. It could be set to zero for now and filled in with the appropriate value as that analysis code becomes available.
Action Item Review
We skipped a detailed review. Doesn't mean there aren't some items out there.
New Action Items
- Circulate a computing resources estimate to the collaboration. -> Mark
- Give a talk on the JANA configuration scheme. -> David
- Deal with warnings in sim-recon from the latest GNU compilers. -> Beni