[Cbc] Cbc Digest, Vol 80, Issue 1

[Fei Peng]

Yep -- i just discovered that. It will be nice to be able to pass a fractional solution as well. There is the setinitialsolution (I think) function for cbcheuristics although fpump is not using it for now.

Fei

> On Feb 1, 2014, at 12:00 PM, cbc-request at list.coin-or.org wrote:
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> Today's Topics:
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>   1. Re: Using CBC as a primal heuristic solver (John Forrest)
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> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Sat, 01 Feb 2014 14:50:33 +0000
> From: John Forrest <john.forrest at fastercoin.com>
> To: cbc at list.coin-or.org
> Subject: Re: [Cbc] Using CBC as a primal heuristic solver
> Message-ID: <52ED09B9.1050207 at fastercoin.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Fei,
> 
> You should be able to pass an integer solution to Cbc e.g. by mipstart 
> and then do RINS.
> 
> If you don't want to do cuts etc in Cbc then set maxnodes to -1.
> 
> I don't think you can use a partial solution for the feasibility pump - 
> an interesting idea though.
> 
> John Forrest
>> On 28/01/14 19:25, Fei Peng wrote:
>> Hi,
>> 
>> I'm new to using CBC, and what I'm trying to do might be a little
>> different from most:
>> 
>> I have a branch-and-price solver that I coded up for my mip problem,
>> from which I'll get various fractional and integer solutions at
>> different nodes. I'd like to use Cbc and its general purpose primal
>> heuristics (e.g. feasibility pump and RINS) to try and find feasible
>> integer solutions to my problem, but I don't want to use Cbc to solve
>> the full problem for me (b/c its too big and slow and that's the
>> reason I'm solving it with B&P).
>> 
>> I can give the full problem to cbc, invoke it and run a number of
>> heuristics at the root node (and maybe a number of additional nodes),
>> however, is there  a way to pass a fractional/integer solution to cbc,
>> and have it run some heuristics just with that solution (e.g. feaspump
>> for fractional and RINS for integer)? I'm not sure if
>> sethotstart/setbestsolution already does that (the reference page is
>> rather vague) but my guess is that a feasible integer sol passed to
>> cbc is used as a new upper bound but not anything else? Please advise
>> 
>> Thanks much!
>> Fei
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> End of Cbc Digest, Vol 80, Issue 1
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