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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hello colleagues,<o:p></o:p></p><p class=MsoNormal>I have noticed something wrong during a call to iterfunc using IPOPT under Matlab. At a given intermediate iteration (the 56<sup>th</sup>, neither the first nor the last one), the x field in the third argument of iterfunc is empty. However, the solver goes on.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Here is the evolution of the optimization:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=FR>iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls<o:p></o:p></span></p><p class=MsoNormal><span lang=FR> </span>50 2.2029586e+001 2.45e-002 1.36e+000 -8.6 8.48e-002 - 8.20e-006 2.58e-001w 1<o:p></o:p></p><p class=MsoNormal>In iteration 50, 1 Slack too small, adjusting variable bound<o:p></o:p></p><p class=MsoNormal> <span lang=ES>51 9.1022741e+001 1.93e+000 1.44e+000 -8.6 2.75e-002 - 1.00e+000 2.74e-001w 1<o:p></o:p></span></p><p class=MsoNormal><span lang=ES> 52 9.1022741e+001 1.91e+000 1.46e+000 -8.6 5.41e-001 - 4.48e-001 9.72e-003w 1<o:p></o:p></span></p><p class=MsoNormal><span lang=ES> 53r3.0398264e+000 1.35e-003 9.99e+002 -2.9 0.00e+000 - 0.00e+000 4.92e-007R 19<o:p></o:p></span></p><p class=MsoNormal><span lang=ES> 54r3.9243117e+000 2.01e-003 1.31e+002 -9.0 1.35e+000 - 8.69e-001 3.87e-007f 1<o:p></o:p></span></p><p class=MsoNormal><span lang=ES> 55r1.2696788e+000 1.46e-009 6.82e+001 -9.0 1.75e-003 - 4.80e-001 8.60e-001f 1<o:p></o:p></span></p><p class=MsoNormal><span lang=ES> 56r1.1584010e+000 6.04e-010 1.72e+001 -9.0 3.51e-003 - 7.47e-001 5.49e-001f 1<o:p></o:p></span></p><p class=MsoNormal><span lang=ES> 57r1.2401559e+000 2.51e-011 6.86e+000 -9.0 1.94e-003 - 6.02e-001 9.73e-001f 1<o:p></o:p></span></p><p class=MsoNormal><span lang=ES> 58 1.2401253e+000 1.83e-011 2.61e-001 -8.6 1.23e-003 - 9.01e-001 2.74e-001h 2<o:p></o:p></span></p><p class=MsoNormal><span lang=ES> </span>59 1.2397894e+000 1.22e-011 1.78e-001 -8.6 2.76e-002 - 1.00e+000 3.34e-001h 1<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>And here are the inputs of iterfunc:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>iter = 56<o:p></o:p></p><p class=MsoNormal>fobj = <span lang=ES>1.158400955836191<o:p></o:p></span></p><p class=MsoNormal><span lang=FR>x = <o:p></o:p></span></p><p class=MsoNormal><span lang=FR> x: []<o:p></o:p></span></p><p class=MsoNormal><span lang=FR> inf_pr: 0.002513493667610<o:p></o:p></span></p><p class=MsoNormal><span lang=FR> inf_du: 17.243376684535178<o:p></o:p></span></p><p class=MsoNormal><span lang=FR> </span>mu: 9.999999999999999e-10<o:p></o:p></p><p class=MsoNormal> d_norm: 0.003511158700339<o:p></o:p></p><p class=MsoNormal> regularization_size: 0<o:p></o:p></p><p class=MsoNormal> <span lang=FR>alpha_du: 0.747343537290606<o:p></o:p></span></p><p class=MsoNormal><span lang=FR> alpha_pr: 0.549440501968642<o:p></o:p></span></p><p class=MsoNormal><span lang=FR> ls_trials: 1<o:p></o:p></span></p><p class=MsoNormal><span lang=ES><o:p> </o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>So, what is actually the x the objective and the other variables were computed for?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Víctor D. Fachinotti<o:p></o:p></p><p class=MsoNormal>CIMEC (UNL/CONICET)<o:p></o:p></p><p class=MsoNormal>Tel: 0342 4511594 interno 7045<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>