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    Hi David -<br>
    <br>
        does it make sense to open a "general ticket" in Mantis about
    the more general<br>
    affects of this issue? <br>
    <br>
      Curtis<br>
    On 3/17/11 11:23 AM, David Lawrence wrote:
    <blockquote cite="mid:4D822754.2070301@jlab.org" type="cite">
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      <br>
      Hi All,<br>
      <br>
          I've just committed a fix to the seg. fault/hang problem based
      on Richard's analysis. This is slightly different than the fix
      Richard suggested. It avoids the 80bit/64bit comparison issue by
      pre-calculating the values to be compared rather than doing it in
      the sort algorithm itself. This should also speed things up a
      little since DVector3::Perp() is not being called repeatedly
      during the sort for the same object. <br>
      <br>
          I have been able to run through my one reliably-problematic
      event using the new code without any problem. If anyone notices an
      issue, please let me know.<br>
      <br>
          This problem has been marked as resolved in Mantis.<br>
      <br>
      Regards,<br>
      -David<br>
      <br>
      -------- Original Message --------
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            <th nowrap="nowrap" valign="BASELINE" align="RIGHT">Subject:
            </th>
            <td>r7587 - trunk/sim-recon/src/libraries/TRACKING</td>
          </tr>
          <tr>
            <th nowrap="nowrap" valign="BASELINE" align="RIGHT">Date: </th>
            <td>Thu, 17 Mar 2011 11:16:40 -0400</td>
          </tr>
          <tr>
            <th nowrap="nowrap" valign="BASELINE" align="RIGHT">From: </th>
            <td><a moz-do-not-send="true"
                class="moz-txt-link-abbreviated"
                href="mailto:Hall-D.SVN.Repository@jlab.org">Hall-D.SVN.Repository@jlab.org</a></td>
          </tr>
          <tr>
            <th nowrap="nowrap" valign="BASELINE" align="RIGHT">To: </th>
            <td><a moz-do-not-send="true"
                class="moz-txt-link-abbreviated"
                href="mailto:davidl@jlab.org">davidl@jlab.org</a>, <a
                moz-do-not-send="true" class="moz-txt-link-abbreviated"
                href="mailto:brash@pcs.cnu.edu">brash@pcs.cnu.edu</a>, <a
                moz-do-not-send="true" class="moz-txt-link-abbreviated"
                href="mailto:wolin@jlab.org">wolin@jlab.org</a>, <a
                moz-do-not-send="true" class="moz-txt-link-abbreviated"
                href="mailto:zisis@uregina.ca">zisis@uregina.ca</a>, <a
                moz-do-not-send="true" class="moz-txt-link-abbreviated"
                href="mailto:mashephe@indiana.edu">mashephe@indiana.edu</a>,
              <a moz-do-not-send="true" class="moz-txt-link-abbreviated"
                href="mailto:remitche@indiana.edu">remitche@indiana.edu</a>,
              <a moz-do-not-send="true" class="moz-txt-link-abbreviated"
                href="mailto:zihlmann@jlab.org">zihlmann@jlab.org</a>, <a
                moz-do-not-send="true" class="moz-txt-link-abbreviated"
                href="mailto:somov@jlab.org">somov@jlab.org</a>, <a
                moz-do-not-send="true" class="moz-txt-link-abbreviated"
                href="mailto:staylor@jlab.org">staylor@jlab.org</a></td>
          </tr>
        </tbody>
      </table>
      <br>
      <br>
      <pre>Author: davidl
Date: 2011-03-17 11:16:39 -0400 (Thu, 17 Mar 2011)
New Revision: 7587

Modified:
   trunk/sim-recon/src/libraries/TRACKING/DTrackCandidate_factory_CDC.cc
Log:
This is a fix for the seg. fault/hang problem that has been plaguing us 
for the last ~4 months. It precalculates the values used in the comparison
in the SortIntersections routine to avoid issues with values calculated
with 80bit precision being compared with values having been copied to and
from a 64bit register. See the report on the GlueX wiki here:

<a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://www.jlab.org/Hall-D/software/wiki/index.php/Diagnosing_segmentation_faults_in_reconstruction_software">http://www.jlab.org/Hall-D/software/wiki/index.php/Diagnosing_segmentation_faults_in_reconstruction_software</a>


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    </blockquote>
    <br>
    <br>
    <pre class="moz-signature" cols="72">-- 
Prof. Curtis A. Meyer           Department of Physics
Phone:  (412) 268-2745          Carnegie Mellon University
Fax:    (412) 681-0648          Pittsburgh PA 15213-3890 
<a class="moz-txt-link-abbreviated" href="mailto:cmeyer@ernest.phys.cmu.edu">cmeyer@ernest.phys.cmu.edu</a>     <a class="moz-txt-link-freetext" href="http://www.curtismeyer.com/">http://www.curtismeyer.com/</a>      

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