[Ipopt] infeasible solution?

[Stefan Vigerske]

Hi,

can you send the Ipopt log?
It's hard to believe that the constraint violation is exactly 0.

I would think that it reports convergence to a point of local 
infeasibility, if it gets to a point in which the constraint violation 
is above the feasibility tolerance ("tol", in the simplest case) and it 
doesn't see a direction in which it can reduce the infeasibility.
For a feasible convex NLP, this should not happen usually.

Stefan

On 06/23/2016 05:37 PM, Chunhua Men wrote:
> Hi, I used IPOPT to solve a convex NLP model. The starting point
> (initial solution) is feasible, but after <100 iterations, IPOPT always
> reports:
>
> "EXIT: Converged to a point of local infeasibility. Problem may be
> infeasible”.
>
> I printed out the final solution: each decision variable is within the
> bounds, and all constraints are met.  From the black console, IPOPT also
> reports "Constraint violation" is zero.  So, it is a feasible solution (though
> may not be optimal).
>
> May I know in which situation, IPOPT would report "Converged to a point of
> local infeasibility"?
>
> My IPOPT version is 3.11.9.9 and it was built in VS 2012 (64-bit) - Win7.
>
> Thanks! Chunhua
>
>
>
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