[Cbc-tickets] [COIN-OR Branch-and-Cut MIP Solver] #89: example where cbc does not find global optimum

[COIN-OR Branch-and-Cut MIP Solver]

#89: example where cbc does not find global optimum
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 Reporter:  janpoland       |       Owner:  somebody
     Type:  defect          |      Status:  new     
 Priority:  major           |   Milestone:          
Component:  component1      |     Version:  2.0     
 Keywords:  global optimum  |  
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 In the following example, I get a feasible solution with cbc (the command
 line version cbcSolver) which is suboptimal. If I use the minimum.cpp call
 instead, cbc does find the optimum, however takes significantly longer
 time.

 The example consists of the following files:
 (1) example.mps : the problem definition
 (2) example_cbc_found1.txt : the solution found by cbc
 (3) example_cbc_found.txt : again the same solution in a different format
 (sparse matrix format where line 1 contains numrows numcols 0, and each
 further line contains i j A[i,j])
 (4) example_optimum.txt : the optimum in sparse matrix format
 (5) otherexample.mps : a very similar (even slightly larger) example where
 cbc does find the global optimum

 I get the problem with different versions of cbc, e.g. 2.3.2. and 2.4.1.
 Many thanks for looking into this!
 Jan.

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Ticket URL: <https://projects.coin-or.org/Cbc/ticket/89>
COIN-OR Branch-and-Cut MIP Solver <http://projects.coin-or.org/Cbc>
An LP-based branch-and-cut MIP solver.