[Cbc] cplex (optimal) vs cbc (infeasible or unbounded)

[Matthew Galati]

Cplex and CBC are giving completely different results on this one. I don't
think this problem is infeasible or unbounded - so I think it might be a CBC
bug.

http://coral.ie.lehigh.edu/~magh/tmp/subProb.n0.c0.p3.b2.lp



Problem 'subProb.n0.c0.p3.b2.lp' read.
Read time =    0.00 sec.
CPLEX> opt
Tried aggregator 1 time.
MIP Presolve eliminated 290 rows and 843 columns.
Reduced MIP has 3 rows, 3 columns, and 6 nonzeros.
Presolve time =    0.00 sec.
Clique table members: 1.
MIP emphasis: balance optimality and feasibility.
Root relaxation solution time =    0.00 sec.

MIP - Integer optimal solution:  Objective = -7.4380291900e+03
Solution time =    0.00 sec.  Iterations = 0  Nodes = 0







Coin Cbc and Clp Solver version 2.30.00, build Dec  1 2008
command line - ./bin/cbc /users/magala/subProb.n0.c0.p3.b2.lp (default
strategy 1)
### WARNING: CoinLpIO::readLp(): Variable x(1) does not appear in objective
function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(7) does not appear in objective
function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(133) does not appear in
objective function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(139) does not appear in
objective function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(145) does not appear in
objective function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(151) does not appear in
objective function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(157) does not appear in
objective function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(163) does not appear in
objective function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(169) does not appear in
objective function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(175) does not appear in
objective function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(393) does not appear in
objective function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(396) does not appear in
objective function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(409) does not appear in
objective function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(472) does not appear in
objective function or constraints
### WARNING: CoinLpIO::readLp(): Variable x(487) does not appear in
objective function or constraints
Coin0508I Presolve thinks problem is unbounded
Continuous objective value is -1.16003e+14 - 0.00 seconds
Coin0508I Presolve thinks problem is unbounded
Cgl0000I Cut generators found to be infeasible!
Pre-processing says infeasible or unbounded
Total time 0.02
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