[BCP] "BM: Couldn't branch!"

[Eric W Anderson]

Another new-user question here:

I have a simple application based on the SHELL example.  The problem is passed
in from Python using SWIG, and the results are passed back out the same way,
but otherwise it's pretty much taken straight from the example.

It always runs fine on small MIPs, but when I give it a modest-sized one (~1500
binary vars), my application frequently dies with the error "BM: Couldn't
branch!".  Here's what I know:

 *  This happens in from BCP_lp_user::select_branching_candidates(...),
    when try_to_branch(...) returns 0 and does not set branchObject.  

 *  That occurs when choose->setupList(&branchInfo, true) returns 0.  (choose
    is an OsiChooseVariable* pointing to an OsiChooseStrong).  

 *  I don't understand OsiChooseStrong, or the general operation of BCP well
    enough to know (a) why this is happening or (b) why it's a bad thing.

Is this problem familiar to anyone?  Any suggestions?  

Thanks again,
Eric


-- 
Eric W. Anderson                                   University of Colorado
eric.anderson at colorado.edu                      Dept. of Computer Science
phone: +1-720-984-8864                   Systems Research Lab - ECCR 1B54

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