reports unbounded problem as infeasible

[svigerske]

Issue created by migration from Trac.

Original creator: @svigerske

Original creation time: 2013-03-01 14:33:54

Assignee: @merraksh

Version:

Hi,

Couenne seems to have problems to recognize unboundedness.

The attached .mod and .nl file are small instances that demonstrate the issue. I get the output:

Couenne  --  an Open-Source solver for Mixed Integer Nonlinear Optimization
Mailing list: couenne`@`list.coin-or.org
Instructions: http://www.coin-or.org/Couenne

NLP0012I 
              Num      Status      Obj             It       time                 Location
NLP0014I             1         OPT 0        4 0.002999
Coin0506I Presolve 0 (-5) rows, 0 (-4) columns and 0 (-10) elements
Clp0000I Optimal - objective value -9.99e+12
Clp0032I Optimal objective -9.99e+12 - 0 iterations time 0.002, Presolve 0.00
Clp0000I Optimal - objective value -9.99e+12
NLP0014I             2         OPT -9.9900001e+12       27 0.009998
Clp0000I Optimal - objective value -9.99e+12
Cbc0006I The LP relaxation is infeasible or too expensive
Cbc0013I At root node, 0 cuts changed objective from -9.99e+12 to -9.99e+12 in 1 passes
Cbc0014I Cut generator 0 (Couenne convexifier cuts) - 0 row cuts average 0.0 elements, 1 column cuts (1 active)
Cbc0001I Search completed - best objective 1e+50, took 0 iterations and 0 nodes (0.01 seconds)
Cbc0035I Maximum depth 0, 0 variables fixed on reduced cost
Clp6002E 1 bad bound pairs or bad objectives were found - first at C0
Clp0004I Stopped due to errors - objective value -9.99e+12

couenne: Infeasible problem

    "Finished"
Total time:                              0.013998s (0.013998s in branch-and-bound)
Lower bound:                                 -inf
Upper bound:                           -2.495e+25  (gap: 0.00%)
Branch-and-bound nodes:                         0

[svigerske]

Attachment unbounded.nl by @svigerske created at 2013-03-01 14:34:33

[svigerske]

Attachment unbounded.mod by @svigerske created at 2013-03-01 14:34:45