[Ipopt] Objective value trouble

Kelly, Jeff (ON0F) jeff.kelly at honeywell.com
Fri Dec 10 08:41:18 EST 2010



BTW - I would have thought that the global minimum is f(x) = -0.5 and x
= -1 whereas f(x=-0.25) = -0.21875.  I also confirmed this Xpress-SLP as




Optimize __OBJ___ :

  x + 0.5 * x ^ 2


Subject To:



-10 <= x <= 10




From: ipopt-bounces at list.coin-or.org
[mailto:ipopt-bounces at list.coin-or.org] On Behalf Of Sebastian Ferrera
Sent: Friday, December 10, 2010 8:22 AM
To: ipopt at list.coin-or.org
Subject: [Ipopt] Objective value trouble


Dear IPopt user community:


I am currently working on a project using the IPopt minimization under


An example for visual studio "csipopt" converges successfully. 


Yet - for the sake of benchmarking - I am trying to minimize the 1D
polynomial f(x) = x + x2/2 under the constraints -10<x<10 and with
initial guess x = 1.

Accordingly the gradient is g(x) = 1 + x and the hessian h(x) = 1. IPopt
fails to find the minimum x=-1/4 as the iterations deviate only
marginally from the initial value as shown by the attached file.


Please advise me how to proceed. I suspect this must be a minor option


Thank you.


Sebastian Ferrera, Chile



-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://list.coin-or.org/pipermail/ipopt/attachments/20101210/5a22d6cc/attachment.html 

More information about the Ipopt mailing list