[Scip] Apply heuristics in each exploration node

[Gregor Hendel]

Hi Cristina,

the heuristic frequency and frequency offset are responsible for
deciding whether or not to apply a heuristic at a given node. A
heuristic is generally applied at every node in depth d if d >=
heurfreqoffset and  (d - heurfreqoffset) % heurfreq == 0.
In addition, the heuristic timing, which cannot be set as a user
parameter, but only when compiling SCIP, plays a role; Diving heuristics,
e.g., are only executed if SCIP is about to leave the current path in
the branch and bound tree.

If you want it executed once per node, a heuristic timing
SCIP_HEURTIMING_AFTERNODE is fine, or more often with
SCIP_HEURTIMING_DURINGLPLOOP, if your heuristic is computationally
inexpensive as, e.g., rounding heuristics usually are.

Please have a look at our doxygen documentation about how to add primal
heuristics:
http://scip.zib.de/doc/html/HEUR.php

Best regards,
Gregor



On 04/24/2014 03:36 PM, Cristina Núñez del Toro wrote:
> Hello,
>
> I'm kind of a SCIP beginner. I would like to know how to implement an
> heuristic algorithm for each exploration node in order to obtain a
> integer solution.
>
> As far as I know, SCIP has several heuristics. What I'm not clear is
> about how to impose the use of a specific one while exploring each of
> the nodes.
>
> Thank you for your help in advance,
>
> Best Regards,
>
> ---
> Cristina Nuñez
>
>
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