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Dear Maxime,
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<div class="">Changing the linear solver should not make any difference as far as I know. I suggest to read up a it on the theory of interior point solvers and derivative-based optimization. Then you’ll be able to understand better why it does not work and
what you can/should do to fix it :)</div>
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<div class="">Kind regards!</div>
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<div class="">Filip <br class="">
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<div class="">Op 6 apr. 2018, om 16:25 heeft Maxime Boulay <<a href="mailto:mboulay@flogen.com" class="">mboulay@flogen.com</a>> het volgende geschreven:</div>
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<span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">Hi Filip,<o:p class=""></o:p></span></div>
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<span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""><o:p class=""> </o:p></span></div>
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<span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">Thank you for your help. Is it possible that using a different linear solver may help to avoid those local points of infeasibility on top of having a good initial
guess?<o:p class=""></o:p></span></div>
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<span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">I am presently using mumps.<o:p class=""></o:p></span></div>
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<span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">Maxime<o:p class=""></o:p></span></div>
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<span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""><o:p class=""> </o:p></span></div>
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<b class=""><span style="font-size: 10pt; font-family: Tahoma, sans-serif;" class="">From:</span></b><span style="font-size: 10pt; font-family: Tahoma, sans-serif;" class=""><span class="Apple-converted-space"> </span>Filip Jorissen [<a href="mailto:filip.jorissen@kuleuven.be" class="">mailto:filip.jorissen@kuleuven.be</a>]<span class="Apple-converted-space"> </span><br class="">
<b class="">Sent:</b><span class="Apple-converted-space"> </span>Friday, April 06, 2018 3:13 AM<br class="">
<b class="">To:</b><span class="Apple-converted-space"> </span>Maxime Boulay<br class="">
<b class="">Cc:</b><span class="Apple-converted-space"> </span><a href="mailto:Ipopt@list.coin-or.org" class="">Ipopt@list.coin-or.org</a><br class="">
<b class="">Subject:</b><span class="Apple-converted-space"> </span>Re: [Ipopt] Infeasible Problem Detected when the problem is actually feasible<o:p class=""></o:p></span></div>
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Hi,<span class="Apple-converted-space"> </span><o:p class=""></o:p></div>
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It sounds like IPOPT converges to a local point of infeasibility? I.e. your equations are non-convex and you need a good/feasible initial guess to be able to converge to a feasible (local) optimum.<o:p class=""></o:p></div>
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Filip<o:p class=""></o:p></div>
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Op 5 apr. 2018, om 17:27 heeft Maxime Boulay <<a href="mailto:mboulay@flogen.com" style="color: purple; text-decoration: underline;" class="">mboulay@flogen.com</a>> het volgende geschreven:<o:p class=""></o:p></div>
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<o:p class=""> </o:p></div>
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<span style="font-size: 11pt; font-family: Calibri, sans-serif;" class="">Hello,<o:p class=""></o:p></span></div>
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<span style="font-size: 11pt; font-family: Calibri, sans-serif;" class="">I am using IpOpt to solve a problem with about 20 variables and 20 constraints. I know the solution to this problem, and I have verified that my constraints are respected at the solution,
there is also no error in the Derivative Checker. However, IpOpt still ends up giving me the Infeasible Problem Detected message when I run it. If I keep running it again with the "warm_start_init_point", it eventually does find the solution. This happens
for many different entry values to this problem. Can anyone help me find a clue as to why this would happen?<span class="apple-converted-space"> </span><o:p class=""></o:p></span></div>
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<span style="font-size: 11pt; font-family: Calibri, sans-serif;" class="">Thank you.<o:p class=""></o:p></span></div>
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<span style="font-size: 11pt; font-family: Calibri, sans-serif;" class="">Maxime<o:p class=""></o:p></span></div>
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