<div dir="ltr">Dear Nicolas,<div><br></div><div>The main benefit with using AMPL or other modeling languages is the exact and (typically) very efficient calculation of first and second order derivative information. Anyway, even if you have some other efficient way of calculating derivatives, changes are that it won't matter much for the speed. The reason for this is that for large-scale problems, most time is typically spent in the linear solver and not in the derivative calculations. This depends on how sparse the problem is, though.</div>
<div><br></div><div>Greetings!</div><div>Joel</div><div><br></div><div>P.S.: You might also want to have look at CasADi (<a href="http://www.casadi.org">www.casadi.org</a>). Like AMPL, it is also able to calculate derivatives very efficiently.</div>
<div><br></div><div class="gmail_extra"><br><br><div class="gmail_quote">2013/7/12 Nicolas Derhy <span dir="ltr"><<a href="mailto:nicolas.derhy@gmail.com" target="_blank">nicolas.derhy@gmail.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr"><div><div><div><div><div>Hi everybody,<br><br></div>I did not find information in the documentation regarding the IPOPT performance.<br></div>I have a lot of small instances to solve and I would prefer to use AMPL because I won't have to write new C++ code.<br>
<br></div>However I do not have any idea of the perfomance gap between these two approaches. I do not know if AMPL calculates jacobian, hessian,... with efficiency and how AMPL and IPOPT communicates (via file, memory ?).<br>
<br></div>Do you have any advice from you IPOPT experience ?<br><br></div>Best regards,<br><br>Nicolas<br></div>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br>Joel Andersson, PhD Student<br>Electrical Engineering Department (ESAT-SCD), Room 05.11,<br>K.U.Leuven, Kasteelpark Arenberg 10 - bus 2446, 3001 Heverlee, Belgium<br>
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