[Couenne-tickets] [Couenne] #33: Counne says "tightened NLP is infeasible"

[Couenne]

#33: Counne says "tightened NLP is infeasible"
----------------------+----------------------------------------------
  Reporter:  thofrei  |      Owner:  pbelotti
      Type:  defect   |     Status:  new
  Priority:  major    |  Milestone:
 Component:  Couenne  |    Version:
Resolution:           |   Keywords:  infeasible Couenne tightened NLP
----------------------+----------------------------------------------

Comment (by thofrei):

 Hi Pietro

 Unfortunately, I get another error message with those options:

 {{{
 WARNING: converting to the 'pyomo solve' subcommand
 [    0.00] Setting up Pyomo environment
 [    0.00] Applying Pyomo preprocessing actions
 [    0.08] Creating model
 [    0.51] Applying solver
 Couenne 0.4 --  an Open-Source solver for Mixed Integer Nonlinear
 Optimization
 Mailing list: couenne at list.coin-or.org
 Instructions: http://www.coin-or.org/Couenne
 Error reading value for tag variable_selection from file.

 Reformulation: 0.2 seconds
 Restoration phase is called at point that is almost feasible,
   with constraint violation 3.455015e-11. Abort.
 Restoration phase is called at point that is almost feasible,
   with constraint violation 3.455015e-11. Abort.
 Loaded instance "/tmp/tmppfHVf7.pyomo.nl"
 Constraints:          549
 Variables:            651 (84 integer)
 Auxiliaries:         2089 (165 integer)

 Cloning TMINLP2TNLPQuadCuts.
 NLP Heuristic: Optimality Based BT: 26 improved bounds
 Probing: 20 improved bounds
 NLP Heuristic: Launching IterativeRounding with parameters:
 Max rounding iter: 10
 Max feas point: 5
 Base lbrhs: 15
 Omega: 0.2
 Max time firstcall: 300
 starting feasibility IR
 Exception of type: FAILED_INITIALIZATION in file
 "../../../../Ipopt/src/Algorithm/IpIpoptAlg.cpp" at line 547:
  Exception message: retval evaluated false: Error while obtaining initial
 iterates.

 couenne: Error encountered in optimization.

         "Aborted"
 A failure has occured but no starting point exists
 Ipopt exited with error code -100 Unrecoverable exception
 [   78.58] Processing results
     Number of solutions: 0
     Solver results file: results.yml
 Problem loading solver results
 ERROR: Unexpected exception while running model Gas_Model_Free_h_EG.py:
         Cannot load a SolverResults object with bad status: error

 }}}

 Do you know how to solve this?

--
Ticket URL: <https://projects.coin-or.org/Couenne/ticket/33#comment:8>
Couenne <https://projects.coin-or.org/Couenne>
Couenne, a solver for non-convex MINLP