Opened 10 years ago

Closed 10 years ago

#55 closed defect (fixed)

CBC produce wrong solution and inconsistent solution between CBC 2.2 and CBC trunk

Reported by: cents Owned by: somebody
Priority: major Component: component1
Version: Keywords: CBC wrong solution trunk
Cc: jjforre@…


I am trying to use CBC to solve two MIP problems. I downloaded 2.2 stable release and trunk and compiled both version on a Linux Ubuntu Hardy Heron distribution.

For the first problem test1.mps. CBC2.2 appears produce correct result but CBC trunk does not produce correct result and the two results are quite different.

For the second problem test2.mps, which is only slightly different from test1.mps. CBC2.2 does generated a solution (I am not sure whether the solution is correct or not), however the objective value in the solution file is obviously wrong because you get a different result by calculating the objective value from the provided solution for the variables. CBC trunk does not seems to solve the problem and produce a different result from CBC2.2.

I used the following command to run the program.

cbc mps_file -max -solve -solution solution file > outputfile

I have attached the mps files and output files in a tgz file for both problems.

test1.mps #mps for problem 1 test1.solution # solution by CBC 2.2 test1.output # output by CBC2.2 test1_trunk.solution #solution by CBC trunk test1_trunk.output # output by CBC trunk

test2.mps #mps for problem 2 test2.solution # solution by CBC 2.2 test2.output # output by CBC2.2 test2_trunk.solution #solution by CBC trunk test2_trunk.output # output by CBC trunk

Please advice.


Change History (1)

comment:1 Changed 10 years ago by forrest

  • Resolution set to fixed
  • Status changed from new to closed

see 56

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