[Scip] A question regarding node selection

Gerald Gamrath gamrath at zib.de
Wed Aug 31 08:29:36 MEST 2011


Hi,

Stefan is right, the priority of the node selectors determine which one 
is called. However, in contrast to the other types of plugins, that are 
called in order of decreasing priority, there is always just one node 
selector used, i.e. the one with the highest priority, since node 
selectors are not allowed skip without selecting a node.

Nevertheless, it is possible to switch the priorities during the solving 
process, which then leads to always calling another node selector first.

Best,
Gerald

Am 30.08.2011 19:31, schrieb Stefan Vigerske:
> Hi,
>
> each nodeselector has it's priority.
> SCIP then employs them in order of decreasing priority, until one of
> them selects a node.
>
> If you type "display nodesel" in the SCIP shell, then you see the
> priorities, per default, "estimate" has the highest priority.
>
> Stefan
>
>> Hello SCIP list!
>>
>> After having (re)read the Coloring example I have a question. In coloringplugins.c the following is stated
>>
>>      SCIP_CALL( SCIPincludeNodeselBfs(scip) );
>>      SCIP_CALL( SCIPincludeNodeselDfs(scip) );
>>      SCIP_CALL( SCIPincludeNodeselEstimate(scip) );
>>      SCIP_CALL( SCIPincludeNodeselHybridestim(scip) );
>>      SCIP_CALL( SCIPincludeNodeselRestartdfs(scip) );
>>
>> I am however puzzled as to which strategy is actually employed with these calls. Some kind of mixture of them? Just the first? Or the last? What decides which strategy is used?
>>
>> Best regards,
>>
>> Tue Christensen
>>
>>
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