[SCIP] Initial primal bounds when solving an NLP globally with SCIP

[Nelson Uhan]

Dear SCIP team,

I'm trying to globally solve an NLP with SCIP (SCIP 7.0.2, compiled with
Ipopt 3.13.5). I've found that sometimes, the local optimal value found by
Ipopt alone is better than the initial primal bounds found by SCIP. I see
this behavior with and without presolving. Is this behavior expected?

This behavior seems counterintuitive to me: after solving the NLP at the
root node with Ipopt, it seems that SCIP should be able to establish a
primal bound equal to the local optimal value that Ipopt alone finds,
unless SCIP runs Ipopt with different settings?

Any guidance you could provide would be really helpful. Thank you very much!

Best regards,
Nelson
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listserv.zib.de/pipermail/scip/attachments/20210722/510a40f7/attachment.html>