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<div class="moz-cite-prefix">Dear Ahmad and list,<br>
<br>
it is possible via SCIP settings to disable almost everything
(presolving, separation) except for a certain heuristic in the
solution process, and set the node limit of this solution process
to 1. You may need to adjust the frequency and frequency offset
parameters of the heuristic to achieve it running at the root
node. E.g., to only run simple rounding, which requires an LP to
be solved, you may call<br>
<br>
set presol emph off<br>
set sepa emph off<br>
set branch random prio 1000000<br>
set lim nodes 1<br>
set heuristics emph off<br>
set heur simplerounding freq 1<br>
read check/instances/MIP/bell5.mps<br>
opt<br>
disp stat<br>
quit<br>
<br>
The statistics will show you that not much more than an LP solve
and simple rounding were executed. By replacing simplerounding
with the name of the heuristic you want to run, you basically get
the solving process to do what you intend.<br>
<br>
Note that in general, the execution of primal heuristics is
connected to particular events during the search. Also, the
working limits for the primal heuristics are determined regarding
statistics of the overall solution process (elapsed search nodes,
elapsed LP iterations).<br>
<br>
Cheers,<br>
Gregor<br>
<br>
<br>
Am 23.12.2016 um 01:26 schrieb Ahmad Moradi:<br>
</div>
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cite="mid:CAND0i1ZhuqnjTm6zwR6mft+CZN=v=eis1auiun32FeEopNoZyQ@mail.gmail.com"
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<div>Dear SCIPers,<br>
<br>
</div>
I would only apply some of the primal heuristics
implemented by SCIP to study the quality of found feasible
solutions and I don't actually need to solve them to
optimality through branch and bound. So,<br>
<br>
Is it possible to <u><i>run</i></u> a primal heuristic of
SCIP on a MIP instance without solving the MIP?</div>
<br>
</div>
Best regards,<br>
</div>
Ahmad<br>
</div>
<br>
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