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<div class="moz-cite-prefix">Pietro,<br>
<br>
Will look into it after INFORMS.<br>
<br>
John<br>
<br>
On 08/11/14 11:56, Pietro Belotti wrote:<br>
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cite="mid:CAA1=4diU4FMiEpUQJ=-n9HGcJhz=H+JhfRyNZVmam9B3oXrLpg@mail.gmail.com"
type="cite">
<pre wrap="">Hello. I am using libCbc to build a convex MINLP solver for a specific
application. The solver is based on Cbc's branch-and-bound and a cut
separator. I have an incomplete problem at every node, since the
linear cuts are a relaxation of a nonlinear (convex) constraint. This
is done through
OsiBabSolver solverChar;
solverChar. setSolverType (3);
dsbb. solver () -> setAuxiliaryInfo (&solverChar);
When configuring with --enable-cbc-parallel, I can run this program in
parallel, but two problems occur:
1) if a time or node limit is given, there are memory leaks at the end
(see the two attachments valg-out2-200nodes.txt and
valg-out2-10s.txt), but no leak happens when reaching optimalitiy (see
valg-out2.txt); most of these seem to be cuts added through addCuts()
at CbcNodeInfo.cpp:354. I have removed non-Cbc output from these
files.
2) The parallel version seems to use more memory than the single-CPU
version at a given time. A back-to-back solve shows that the parallel
version uses 2x the memory of the sequential one even when they are
exploring the same number of nodes; memory occupation is the same
until the BB starts.
It should be emphasized that this solver generates a large number of
cuts, and for some instances after 500,000 nodes it is killed after
using the 240GB memory limit. I could not replicate this with the
console version of parallel cbc with time/node limit on a MILP, so I
suspect I might be doing something wrong. Has anything like this
happened in the past?
Thanks,
Pietro
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