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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Sebastian;<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>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 well.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Jeff <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:"Courier New"'>Optimize __OBJ___ :<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:"Courier New"'> x + 0.5 * x ^ 2<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:"Courier New"'>Subject To:<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:"Courier New"'>Bounds:<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:"Courier New"'>-10 <= x <= 10<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:"Courier New"'>End<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> ipopt-bounces@list.coin-or.org [mailto:ipopt-bounces@list.coin-or.org] <b>On Behalf Of </b>Sebastian Ferrera Ferrera<br><b>Sent:</b> Friday, December 10, 2010 8:22 AM<br><b>To:</b> ipopt@list.coin-or.org<br><b>Subject:</b> [Ipopt] Objective value trouble<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=ES>Dear IPopt user community:<o:p></o:p></span></p><p class=MsoNormal><span lang=ES><o:p> </o:p></span></p><p class=MsoNormal><span lang=ES>I am currently working on a project using the IPopt minimization under contraints.<o:p></o:p></span></p><p class=MsoNormal><span lang=ES><o:p> </o:p></span></p><p class=MsoNormal><span lang=ES>An example for visual studio “csipopt” converges successfully. <o:p></o:p></span></p><p class=MsoNormal><span lang=ES><o:p> </o:p></span></p><p class=MsoNormal><span lang=ES>Yet - for the sake of benchmarking - I am trying to minimize the 1D polynomial f(x) = x + x<sup>2</sup>/2 under the constraints -10<x<10 and with initial guess x = 1.<o:p></o:p></span></p><p class=MsoNormal><span lang=ES>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 <span style='color:#1F497D'>file</span>.<o:p></o:p></span></p><p class=MsoNormal><span lang=ES><o:p> </o:p></span></p><p class=MsoNormal><span lang=ES>Please advise me how to proceed. I suspect this must be a minor option setting.<o:p></o:p></span></p><p class=MsoNormal><span lang=ES><o:p> </o:p></span></p><p class=MsoNormal><span lang=ES>Thank you.<o:p></o:p></span></p><p class=MsoNormal><span lang=ES><o:p> </o:p></span></p><p class=MsoNormal><span lang=ES>Sebastian Ferrera, Chile<o:p></o:p></span></p><p class=MsoNormal><span lang=ES><o:p> </o:p></span></p><p class=MsoNormal><span lang=ES><o:p> </o:p></span></p></div></body></html>