[Cbc] CLI-like solve with API

[John Forrest]

Matthew,

I get identical results using driver4.cpp and cbc executable - if you 
don't then maybe I can track it down.

In your example it would be OsiClpSolverInterface iface and maybe there 
is some subtle difference between reading an mps file and ConstructModel.

John Forrest
On 28/07/14 18:43, Matthew Gidden wrote:
> Hi all,
>
> I just wanted to report back. I've been hunting for the actual main 
> function used by the CLI, and as best I can tell it's in 
> CoinSolve.cpp. It doesn't appear that there's anything extra going on 
> between CbcMain0 and CbcMain1. Accordingly, it's unclear to me why a 
> call to `cbc` from the command line returns a solution consistently 
> faster than using the API by a factor of ~2-3 for smallish problems. 
> To be clear, I do the following:
>
>     OsiCbcSolverInterface iface;
>     ConstructModel(iface);
>
>     int argc = 3;
>     const char *argv[] = {"exchange","-solve","-quit"}; 
>
>     CbcMain0(*iface->getModelPtr());
>     CbcMain1(argc, argv, *iface->getModelPtr(), callBack);
>
>
> I'm going to leave this for now (unless someone has a clear idea as to 
> what the difference may be). Using CbcMain0/1 provides me a 
> substantial speed up (3 orders of magnitude) over naively calling 
> branchAndBound, as one might expect.
>
> I would still be very interested in any documentation regarding the 
> heuristics, cuts, branching strategies, etc. used in CbcMain1 (again, 
> 8k+ lines of code is burdensome to investigate). I would also be very 
> interested if anyone has any open source drivers that do something 
> like CbcMain1 (i.e., apply 'generally good' heuristics, cuts, etc.) 
> but maintains the unsolved model in order to provide user-specified, 
> additional options.
>
> Again, I apologize if this is old hat for the community; I'd also like 
> to specifically thank John and Rolf for assisting.
>
> Cheers,
>
>
>
> On Sun, Jul 27, 2014 at 10:02 AM, Matthew Gidden <gidden at wisc.edu 
> <mailto:gidden at wisc.edu>> wrote:
>
>     Hi John,
>
>
>
>
>     On Sat, Jul 26, 2014 at 1:45 PM, John Forrest
>     <john.forrest at fastercoin.com <mailto:john.forrest at fastercoin.com>>
>     wrote:
>
>         Matthew,
>
>         Look at driver4.cpp in Cbc/examples.
>
>     I'm playing around with this right now. Just using CbcMain0 and
>     CbcMain1 get's within an order of magnitude of the CLI execution.
>     I'll keep at it. Thanks for the input!
>
>         You could easily turn some of that into your SolveModelLikeCli
>         (with optional string of parameters).
>
>         John Forrest
>
>
>         On 26/07/14 00:06, Matthew Gidden wrote:
>>         Hi all,
>>
>>         I've discovered that the cbc CLI does a pretty good job at
>>         solving my class of problems.  In short, I'm curious if
>>         there's a way to get that rich functionality at the API
>>         level. Ideally, I'd like to do something like the following:
>>
>>             model = ConstructModel();
>>             SolveModelLikeCLI(model); 
>>
>>
>>         It looks like the implementation is one long function
>>         (cbcMain1 is 8k+ lines) and would be incredibly difficult to
>>         cherry-pick implementation from it. I've scoured the API docs
>>         and haven't found anything that looks promising.
>>         Alternatively, is there a listing of all the heuristics,
>>         cuts, branching strategies, etc., used by the default CLI?
>>
>>         Sorry if this is an obvious question; I was hoping to
>>         leverage the features already implemented before
>>         reimplementing something myself.
>>
>>         -- 
>>         Matthew Gidden
>>         Ph.D. Candidate, Nuclear Engineering
>>         The University of Wisconsin -- Madison
>>         Ph. 225.892.3192 <tel:225.892.3192>
>>
>>
>>         _______________________________________________
>>         Cbc mailing list
>>         Cbc at list.coin-or.org  <mailto:Cbc at list.coin-or.org>
>>         http://list.coin-or.org/mailman/listinfo/cbc
>
>
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>
>
>
>     -- 
>     Matthew Gidden
>     Ph.D. Candidate, Nuclear Engineering
>     The University of Wisconsin -- Madison
>     Ph. 225.892.3192 <tel:225.892.3192>
>
>
>
>
> -- 
> Matthew Gidden
> Ph.D. Candidate, Nuclear Engineering
> The University of Wisconsin -- Madison
> Ph. 225.892.3192

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