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<p class="MsoNormal"><span style="color:#1F497D">Hi Martijn,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">In my experience C-MEX S-Functions can be difficult, and even more so with the need to generate real-time code. You might like to start with one of my other packages (jMPC Toolbox) which implements linear MPC
using C-MEX S-Functions:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><a href="http://i2c2.aut.ac.nz/Resources/Software/jMPCToolbox.html">http://i2c2.aut.ac.nz/Resources/Software/jMPCToolbox.html</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">As with the OPTI Toolbox, all source is provided so you can see how to begin implementing an S Function (and even better, MPC). However you will need a C-MEX function which calls IPOPT. You can dynamically link
IPOPT (build a DLL) to a MEX file, or statically link as I have done in OPTI. Compiling IPOPT from source (including all prerequisites) can be tricky on Windows so let me know if you want a static library build, I think I am allowed to distribute it. Just
note the MATLAB interface to IPOPT (by Dr. Carbonetto) is reasonbly complex and this will be need to be reimplemented in a S Function (hope you are a good C++ programmer). Also make sure to use the warm-start functionality of IPOPT, something MPC can greatly
benefit from.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Regarding the need to generate real time code, I'm not sure exactly how this will work with IPOPT. I doubt that will work with the xPC Target, however It should (although I have not tried) work with the Real
Time Windows Target. You are probably best to ask a question in the Matlab User Forum regarding using 3rd party code within it's real time code execution environment.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I would be interested in your progress, so keep me posted on developments!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Jonathan Currie<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" 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>Martijn Disse<br>
<b>Sent:</b> Wednesday, 30 May 2012 7:53 a.m.<br>
<b>To:</b> ipopt@list.coin-or.org<br>
<b>Subject:</b> [Ipopt] Question: Using IPOPT as an S-function in Simulink<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB">Dear all,<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB">For my thesis work I am using IPOPT as a solver for a Model Predictive Controller. IPOPT is open source and exist of a large collection of files written in C++. I installed the solver to be
used with Matlab via the OPTI-Toolbox (</span><span lang="NL"><a href="http://www.i2c2.aut.ac.nz/Resources/Software/OptiToolbox.html"><span lang="EN-GB">http://www.i2c2.aut.ac.nz/Resources/Software/OptiToolbox.html</span></a></span><span lang="EN-GB">) which
come with a precompiled mex-file that acts as a function to call the solver. This works perfectly. However, since I need to use XPC-target or Windows Real Time Target, I need to implement the solver somehow in a Simulink block.
<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB">This is what I've tried so far:<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo2;text-autospace:none">
<![if !supportLists]><span lang="EN-GB" style="font-family:Symbol"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-GB">Since I already have a mex-file I thought it would be convienent to use that inside a simple 'Matlab Function'-block. This works in Simulink, but the code generator cannot compile the Simulink diagram to a real-time
executable code.<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo2;text-autospace:none">
<![if !supportLists]><span lang="EN-GB" style="font-family:Symbol"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-GB">Creating an S-function in which I call the .mex function. This code cannot be compiled since the .tlc file is missing.<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB">After some search on
<a href="http://www.mathworks.se/matlabcentral/answers/38962-call-a-mex-function-from-simulink">
fora</a> and <a href="http://www.mathworks.com/matlabcentral/answers/36879-calling-mex-function-from-within-simulink">
Matlab central</a>, I found out that I should create a C MEX S-function and compile it. To make life easier, Simulink comes with an S-function builder in which libraries etc. can be added. I failed in constructing one and it is driving me crazy. My question
to you therefor is:<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><b><span lang="EN-GB">Who has experience in compiling IPOPT (or any other set of C++ files) to act as an S-function in Simulink and is willing to point me in the right direction?<o:p></o:p></span></b></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB">Your help will be greatly appreciated!<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="NL">Best,<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="NL">Martijn <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="NL"><o:p> </o:p></span></p>
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