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Hi All,<br>
<br>
One thing to keep in mind is that the BCAL simulation had a
significant revision done last fall that was <br>
disabled soon after implementation. The disabling was to be a
temporary measure until someone was<br>
able to work on the BCAL reconstruction to make it use the new
simulation data format (not a 1 hour<br>
task). If we freeze GEANT3 now, both BCAL simulation algorithms will
need to be ported to GEANT4. <br>
Even the disabled one. I'm not arguing that we shouldn't do it now.
Just that Richard should be aware<br>
that this will be a part of the task.<br>
<br>
Regards,<br>
-David<br>
<br>
<div class="moz-cite-prefix">On 1/30/13 4:25 PM, Curtis A. Meyer
wrote:<br>
</div>
<blockquote cite="mid:46600B1D-1B34-4CF4-821C-4239A3319158@cmu.edu"
type="cite">It feels to me that it would be a good time to freeze
GEANT3 and force a migration to GEANT4. We have
<div>a lot to do with our data challenge right now that will keep
us busy without doing things to GEANT, and</div>
<div>as Matt said, getting this done now may well be our last
chance to do it in a sensible way that minimizes</div>
<div>work being done twice when we get data.</div>
<div> Curtis<br>
<div apple-content-edited="true">
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<div style="word-wrap: break-word; -webkit-nbsp-mode:
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<div>-------</div>
<div>Prof. Curtis A. Meyer<span class="Apple-tab-span"
style="white-space: pre; "> </span> <span
class="Apple-converted-space"> </span>Department of
Physics</div>
<div>Phone: (412) 268-2745<span class="Apple-tab-span"
style="white-space: pre; "> </span> <span
class="Apple-converted-space"> </span>Carnegie
Mellon University</div>
<div>Fax: (412) 681-0648<span
class="Apple-tab-span" style="white-space: pre; "> </span>
Pittsburgh, PA 15213</div>
<div><a moz-do-not-send="true"
href="mailto:curtis.meyer@cmu.edu">curtis.meyer@cmu.edu</a>
<a moz-do-not-send="true"
href="http://www.curtismeyer.com/">http://www.curtismeyer.com/</a></div>
<div><br>
</div>
<div><br>
</div>
</div>
</span><br class="Apple-interchange-newline">
</span><br class="Apple-interchange-newline">
</div>
<br>
<div>
<div>On Jan 30, 2013, at 1:34 PM, Matthew Shepherd wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
<div><br>
Hi software gurus,<br>
<br>
Many years ago we decided that migrating to Geant4 was not
a high priority for our software activities, although our
software was intentionally designed to facilitate a
migration at a later date. With the generation of the
first data challenge now under our belt, I wonder if we
want to revisit this decision?<br>
<br>
I think there are two main reasons to consider making a
switch:<br>
<br>
Running CERNLIB on modern operating systems is a real
headache. I know there are working solutions that allow
us to function, but they work on only some OS'es and
involve downloading patched code a private developer.
CERNLIB has no official support and overall this results
in a net productivity loss for us since we depend on it
and it generates a lot of frustration for people trying to
get our software running.<br>
<br>
The second, more significant reason is that, if we are
going to switch to Geant4, we want to have fully made the
transition to Geant4 by the time we start taking data.
One of the most time consuming and challenging aspects of
analyses is understanding the systematic uncertainties in
efficiency due to the fact that the Monte Carlo isn't a
perfect model of the detector. We'd like to only go
through this once: we don't want to do it once for Geant3
and then again for Geant4. Geant3 is fine for the
exercises we are doing now, but if we're ever going to
make the switch, it would be wise to do it well before we
start taking data.<br>
<br>
Of course it is always easy for someone to propose work
when that person is not the one actually doing the work!
The burden would fall on the Geant expert (or experts, do
we have more than one?) in our group. I know that
Richard reported last year that significant progress had
been made in porting code to Geant4. <br>
<br>
Maybe we can bring this up for discussion at a future
software meeting or discuss more through this email
thread. Maybe the right answer is that it is still not a
high priority item -- I think it merits a little
discussion again though. (Maybe you already talked about
it during one of the many software meetings I missed last
fall!) <br>
<br>
Matt<br>
<br>
<br>
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