[Ipopt] dual of a constraint

Hossein Haghighat hosein.haghighat at gmail.com
Wed Feb 22 23:23:45 EST 2012

Hi all,
I use Ipopt to get the dual of a constraint in a NLP model in ampl. I have
also tried other solvers including Minos and Knitro to compare these value.
They give three different results.
can anybody tell me which value can be trusted? is there any method e.g.
problem reformulation or addition of extra terms to objective or
constraints, to get the same value from different solvers?
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://list.coin-or.org/pipermail/ipopt/attachments/20120223/efdf85b7/attachment.html>

More information about the Ipopt mailing list