on which variable does gurobi do branching in each node of MIPNODE callback

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Sina Rastani

• October 18, 2019 09:19

Hi,

 

I am looking for a way to get the decision variable that gurobi branches on it in each node of the branch and bound in MIPNODE callback.

Also I need to know does the following statement is for depth-first algorithm? if not can you suggest a way to apply depth-first in implementing the branch and bound?

model.setParam('BranchDir', -1) 
# A value of -1 will always explore the down branch first

 

Thanks,

Sina

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  Silke Horn

  • October 21, 2019 08:09

  Hi Sina,

  You cannot get information about the branching. (Also note that the variables that Gurobi branches on may not be your variables at all since the model is transformed during presolve.)

  As for the BranchDir parameter, this determines the order in which the current node's child nodes are explored. The terms "down branch" and "up branch" refer to rounding down or up. (E.g. the down branch is the one where the branching variable is rounded down.) There is no setting for depth-first-search.

  Silke

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  Sina Rastani

  • October 22, 2019 09:13

  Hi Sike,

  I get it. Thanks for your explanation.

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