[Coin-discuss] Cbc branchAndBound

[John J Forrest]

cbc has lots that is not in CbcStrategyDefault.

I have not got time to do much for a week or so, but there are options to
the CbcStrategyDefault constructor - so try setting preprocessing and cuts
in tree and see what you think - see examples/strategy.cpp.  Also there are
more heuristics - see examples/strategy2.cpp

I have not had time to test either example.

John Forrest


                                                                           
             "Matthew Galati"                                              
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             03/15/07 09:53 AM         RE: [Coin-discuss] Cbc              
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Hi -- lots of related discussion on other threads. Solutions all seem to
involve a re-design or new version of OSI.

Can someone just answer this simple question?
  CbcModel cbc(*si);
  CbcStrategyDefault cbcStrategyDefault;
  cbc.setStrategy(cbcStrategyDefault);
  cbc.branchAndBound();

Is this approximately equivalent to what is in CoinSolve.cpp? From
experimentation, just running cbc.branchAndBound() without setting the
strategy is a bad idea.

I don't care what interface I need to use CbcModel::branchAndBound(),
OsiCbc::branchAndBound(), FunkyChickenDance::solveMyMip() -- I just want to
solve a (generic) MILP (with the best known default settings) that is
currently stored in an OSI object. How do I do that?

Thanks.
From: coin-discuss-bounces at list.coin-or.org
[mailto:coin-discuss-bounces at list.coin-or.org] On Behalf Of Matthew
Galati
source software for Operations Research
branchAndBound
seem to be on:
  CbcModel cbc(*si);
  CbcStrategyDefault cbcStrategyDefault;
  cbc.setStrategy(cbcStrategyDefault);
  cbc.branchAndBound();
CoinSolve.cpp? I looked at the CoinSolve.cpp main( ), and there seems to be
a lot going on there - and it is hard to follow. I would suspect that
libCbc should have the same functionality and performance as the cbc
executable. Maybe some of CoinSolve needs to be moved back into the
library? So that the solve part of main() just calls cbc.solve(), or
something like this.
From: coin-discuss-bounces at list.coin-or.org
[mailto:coin-discuss-bounces at list.coin-or.org] On Behalf Of Matthew
Galati
source software for Operations Research
branchAndBound
   CbcModel cbc(*si);
   cbc.branchAndBound( );
performs much worse than if I were to solve using the CBC exe from
CoinSolve.cpp. Apparently, by default branchAndBound() has all cuts, etc
turned off. What's the best interface from CbcModel to solve a MIP so that
it performs like the CBC exe?

Thanks,
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