[Coin-ipopt] Lagrange Multipliers in AMPL

Karsten Theissen tbb at math.uni-muenster.de
Wed Apr 28 04:50:30 EDT 2004

Hello IPOPT-Experts,

after some problems in the beginning, everything is working now! Everything?? 
Of course not ;-), but i think it is only a small problem.

I test all my old and new AMPL-LOQO problems with IPOPT (and by the way IPOPT 
is doing a great job...) but there are some problems with the Lagrange 
multipliers. When I was working with LOQO you can get them by evaluating the 
name of your constraints e.g. with

s.t. dgl1{i in 0..Nt-1}:

you get them with

dgl1[i]     i=1..Nt-1

I think with IPOPT it should be the same but there are all equal to zero. 
Maybe it is only a question of a missing ipopt_option.
It would be nice if anybody could help.


Karsten Theißen

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