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COPT-Public / COPT.jl

Julia interface for COPT (Cardinal Optimizer)
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Partial MIP start is not properly supported #38

Open mzy2240 opened 5 months ago

mzy2240 commented 5 months ago

If I understand the manual correctly, MipStartMode=2 has to be explicitly set in order to make the partial MIP start work. I checked the source code of COPT.jl but did not find a place where the parameter is set.

NCKempke commented 2 months ago

Hi @mzy2240, yes, you are right. If you supply a partial MIP starting solution to COPT, MipStartMode=2 has to be set.

This currently has to be done with intent. By default, COPT currently will only accept full start solutions. However, you can set the parameter yourself for now via the Julia interface.

I'll discuss with others, and see whether we want to change this behavior.

NCKempke commented 2 months ago

@mzy2240 thanks for bringing this up. We have decided to change our default behavior with the next release. From then on, the default COPT behavior will allow for partial and full MIP starts - so no need to set anything anymore.

Until then, one will have to set the value manually through the Julia interface.