Opened 9 years ago

Closed 7 weeks ago

#89 closed defect (migrated)

example where cbc does not find global optimum

Reported by: janpoland Owned by: tkr
Priority: major Component: component1
Version: 2.4.1 Keywords: global optimum
Cc:

Description

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.

Attachments (1)

cbc_suboptimal.zip (48.9 KB) - added by janpoland 9 years ago.

Download all attachments as: .zip

Change History (3)

Changed 9 years ago by janpoland

comment:1 Changed 9 years ago by tkr

  • Owner changed from somebody to tkr
  • Status changed from new to assigned
  • Version changed from 2.0 to 2.4.1

comment:2 Changed 7 weeks ago by stefan

  • Resolution set to migrated
  • Status changed from assigned to closed

This ticket has been migrated to GitHub and will be resolved there: https://github.com/coin-or/Cbc/issues/89

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