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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">I’m running a fairly simple, though quite long and memory demanding, simulation on a HPC computer.
<o:p></o:p></p>
<p class="MsoNormal">The simulation has to be split on various CPUs using gjs. The problem that I’ve encountered is that, for some root files, the following error appears:<o:p></o:p></p>
<p class="p1"><span class="s1"><span style="font-size:12.0pt">This error is symptomatic of a Tree created as a memory-resident Tree</span></span><o:p></o:p></p>
<p class="p1"><span class="apple-converted-space"><span style="font-size:12.0pt"> </span></span><span class="s1"><span style="font-size:12.0pt">Instead of doing:</span></span><o:p></o:p></p>
<p class="p1"><span class="apple-converted-space"><span style="font-size:12.0pt">
</span></span><span class="s1"><span style="font-size:12.0pt">TTree *T = new TTree(...)</span></span><o:p></o:p></p>
<p class="p1"><span class="apple-converted-space"><span style="font-size:12.0pt">
</span></span><span class="s1"><span style="font-size:12.0pt">TFile *f = new TFile(...)</span></span><o:p></o:p></p>
<p class="p1"><span class="apple-converted-space"><span style="font-size:12.0pt"> </span></span><span class="s1"><span style="font-size:12.0pt">you should do:</span></span><o:p></o:p></p>
<p class="p1"><span class="apple-converted-space"><span style="font-size:12.0pt">
</span></span><span class="s1"><span style="font-size:12.0pt">TFile *f = new TFile(...)</span></span><o:p></o:p></p>
<p class="p1"><span class="apple-converted-space"><span style="font-size:12.0pt">
</span></span><span class="s1"><span style="font-size:12.0pt">TTree *T = new TTree(...)</span></span><o:p></o:p></p>
<p class="MsoNormal">From root documentation (<a href="https://root-forum.cern.ch/t/a-tree-created-as-a-memory-resident-tree/16496">https://root-forum.cern.ch/t/a-tree-created-as-a-memory-resident-tree/16496</a>), I understand that by creating the TTree before
the TFile, the TTree exists in memory (which is inefficient, if you want to store high amounts of data). What I don’t understand though, is why this error appears in some of my files, but not in all of them - As the simulation times are split evenly and the
CPU resources are the same for all my simulation <o:p></o:p></p>
<p class="MsoNormal">My questions are then, (i) Why is this happening only in a few files but not all? (ii) Has this been fixed in recent gate versions?<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Regards,<o:p></o:p></p>
<p class="MsoNormal">Francisco Enriquez<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
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