[Ipopt-tickets] [Ipopt] #179: solution not within bounds when all variables are fixed

[Ipopt]

#179: solution not within bounds when all variables are fixed
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Reporter:  stefan  |      Owner:  ipopt-team
    Type:  defect  |     Status:  new
Priority:  normal  |  Component:  Ipopt
 Version:  3.10    |   Severity:  normal
Keywords:          |
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 Hi,

 I have a situation where I run Ipopt on a problem where all variables are
 fixed.
 Additionally, I pass a starting solution that is different from the
 variable fixings (and thus outside the bounds).

 Ipopt nicely recognizes that everything is fixed and the point is
 feasible.
 In TNLPAdapter::GetSpaces it then calls my finalize_solution method with
 the values of the variable-fixings.
 Then a NO_FREE_VARIABLES_BUT_FEASIBLE exception is thrown and catched
 again in IpoptApplication.
 Unfortunately, here my finalize_solution method is called again, and for
 reasons that I have not found yet, it passes the infeasible start solution
 instead of the variable-fixings.

 A guess is, that TNLPAdapter::GetStartingPoint stores the wrong values in
 p2ip_data->curr()->x(), which are usually overwritten during a second call
 to GetBoundsInformation, but not in this case.

 Stefan

 PS: I used ReOptimizeNLP() to solve this NLP.

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Ticket URL: <https://projects.coin-or.org/ticket/179>
Ipopt <http://projects.coin-or.org/Ipopt>
Interior-point optimizer for nonlinear programs.