[Coin-ipopt] question on "overall NLP error"

[tmtuan at laas.fr]

Hi Andreas and all,

I suppose that the derivative check module is very useful, I used it to
fix gradient calculation and now my program runs quite well. But although
the obtained result is good, I found that "dual infeasibility" in the
output of the program is still high (around 1.0e02) (the number for
"overall NLP error" is the same).
So I wonder what is the role of "dual infeasibility" into the solution and
whether we can have a good result even this error is not perfect.
By the way, how do the "constraint violation" and "complementarity" are
calculated and their signification ? They are not cummulated to "overall
NLP error" ?

Thanks for your answers,