[Couenne-tickets] [Couenne] #25: reports unbounded problem as infeasible

[Couenne]

#25: reports unbounded problem as infeasible
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 Reporter:  stefan   |      Owner:  pbelotti
     Type:  defect   |     Status:  new
 Priority:  minor    |  Milestone:
Component:  Couenne  |    Version:
 Keywords:           |
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 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 at 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
 }}}

-- 
Ticket URL: <https://projects.coin-or.org/ticket/25>
Couenne <https://projects.coin-or.org/Couenne>
Couenne, a solver for non-convex MINLP