[Cbc] CLI-like solve with API

[Matthew Gidden]

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> wrote:

> Hi John,
>
>
>
>
> On Sat, Jul 26, 2014 at 1:45 PM, John Forrest <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
>>
>>
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>>
>>
>>
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>>
>
>
> --
> Matthew Gidden
> Ph.D. Candidate, Nuclear Engineering
> The University of Wisconsin -- Madison
> Ph. 225.892.3192
>



-- 
Matthew Gidden
Ph.D. Candidate, Nuclear Engineering
The University of Wisconsin -- Madison
Ph. 225.892.3192
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