Minutes from May 23 offline meeting posted

[David Lawrence <davidl@jlab.org>]

Hi Folks,

    The minutes from last Friday's offline software meeting have been 
posted on the wiki at:

http://www.jlab.org/Hall-D/software/wiki/index.php/May._23%2C_2008_Software

I have also copied them below for convenience.

Regards,
-David

==Minutes==

Attendees: David L., Matt S., Elton S., Alex S., Elliott W., Simon T., 
Mark I., Beni Z.

===Recent Changes To JANA===
David presented some [[Media:20080523_RecentJANAUpdates.pdf | slides]] 
on recent updates to the ''JANA'' framework. These included adding 
associated objects to existing data objects, incorporating ''autoconf'' 
in the build procedure, and revamping the entire mechanism for printing 
single data objects to the screen.

It was mentioned during the presentation that the new "toStrings" 
methods provide the possibility of doing some type of automated I/O of 
objects. Elliott noted advancements in the BOOST library regarding 
object persistence that my be useful. He and David would discuss it 
offline to see if any advantage could be gained from there.


===Geometry Access in DANA===
David presented some [[Media:20080523_GeometryAccess.pdf | slides]] on 
recent updates to DANA (and JANA) that now allow access to the XML-based 
geometry info. from within the reconstruction code. The XML itself can 
be queried via an XPATH-like syntax. Because the "view" of the data 
represented in the XML is geared toward GEANT, it is not necessarily the 
optimal view for the reconstruction code. The example of the z-locations 
of an FDC wire plane was given. This number is a sum of several 
locations from the nested geometry structure represented in the XML. 
Therefore a single XPATH could not be specified to find it. To address 
this, a set of "convenience" methods have been set up in the 
''DGeometry'' class that encapsulate much of the specific knowledge 
about what structure of the geometry is in order to extract the 
appropriate numbers and combine them into the values useful to 
reconstruction.

Some discussion was have with suggestions on possible alternatives to 
the "convenience" methods. These where:

# From Beni: ''hdgeant'' already produces a ROOT file with geometry info 
in it, including the relationship between volumes. One might be able to 
use this along with existing ROOT methods to extract the desired info 
using a single call (again, think FDC wire plane Z-position)
# From Elliott: Instead of doing the conversions of these numbers every 
time the program is run, one might be able to convert the geant-biased 
XML into a reconstruction-biased XML. Possibly, using XSLT.

These options will be explored in the near future.


==[[Action Items From Hall-D Software Meetings|Action items]]==
''No action items were discussed''

==Next Meeting==
It had been planned to have Sebastien Procureur come and give us an 
informal presentation on the tracking work he has been doing for CLAS12 
at our next offline meeting. However, due to scheduling conflicts it was 
suggested that his presentation be moved to the tracking meeting. 
Announcements will be sent out once the scheduling is resolved.


-- 

------------------------------------------------------------------------
  David Lawrence Ph.D.
  Staff Scientist                 Office: (757)269-5567   [[[  [   [ [       
  Jefferson Lab                   Pager:  (757)584-5567   [  [ [ [ [ [   
  http://www.jlab.org/~davidl     davidl@jlab.org         [[[  [[ [[ [[[
------------------------------------------------------------------------