faq.htm

国外专家做的求解LMI鲁棒控制的工具箱,可以相对高效的解决LMI问题

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        <p style="margin-bottom: 0; margin-top:0"><font color="#0000FF"><b>A</b></font><b><font color="#0000FF">:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0">Do you have any solver 
        installed?</p>
        </td>
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    </table>
    <p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
    <table border="0" cellpadding="0" style="border-collapse: collapse" width="100%">
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        <p style="margin-bottom: 0; margin-top:0"><b><font color="#0000FF">
        <a name="compile solver"></a>Q:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0"><b>...still doesn't work!</b></td>
      </tr>
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><font color="#0000FF"><b>A</b></font><b><font color="#0000FF">:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0">Compiled the solver (if needed)? 
        Compiled it for the correct MATLAB version?</p>
        </td>
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    </table>
    <p style="margin-top: 0; margin-bottom: 0">&nbsp;</p>
    <table border="0" cellpadding="0" style="border-collapse: collapse" width="100%">
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        <p style="margin-bottom: 0; margin-top:0"><b><font color="#0000FF">
        <a name="compile solver2"></a>Q:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0"><b>...still doesn't work!</b></td>
      </tr>
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><font color="#0000FF"><b>A</b></font><b><font color="#0000FF">:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0">Using MATLAB 5.3.1 or later?</p>
        </td>
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    </table>
    <p style="margin-top: 0; margin-bottom: 0">&nbsp;</p>
    <table border="0" cellpadding="0" style="border-collapse: collapse" width="100%">
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><b><font color="#0000FF">
        <a name="compile solver0"></a>Q:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0"><b>...still doesn't work!</b></td>
      </tr>
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><font color="#0000FF"><b>A</b></font><b><font color="#0000FF">:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0">Probably a PICNIC problem ;-P</p>
        </td>
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    </table>
    <p style="margin-top: 0; margin-bottom: 0">&nbsp;</p>
    <table border="0" cellpadding="0" style="border-collapse: collapse" width="100%" id="table1">
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><b><font color="#0000FF">
        <a name="slow"></a>Q:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0"><b>It is so slow!</b></td>
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><font color="#0000FF"><b>A</b></font><b><font color="#0000FF">:</font></b></td>
        <td>
    <p style="margin-bottom: 0; margin-top:0">As a rule of thumb, the time 
    reported as <code>'yalmiptime'</code> in the output diagnostic should be around fractions 
    of a second for small problems, and typically a fraction of the actual 
    solution time for larger problems. If this is not the case, you probably 
    have a problem with your installation.</p>
	<p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
	<p style="margin-bottom: 0; margin-top:0">As another rule of thumb, <code>yalmiptest(sdpsettings('verbose',0,'solver','sedumi'))</code> 
	takes 2-5 seconds (including initial search for solvers) on my PC machines 
	(2GHz and 3GHz).</p>
    <p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
    <p style="margin-bottom: 0; margin-top:0">Do you have FEMLAB on your MATLAB 
    path? Removing FEMLAB from the path can improve performance significantly. 
    Another way to make YALMIP faster is to set the field <code>cachesolvers</code> 
          in <a href="#sdpsettings">sdpsettings</a> to 1. (One reason for the 
    extremely poor performance of YALMIP in these cases is typically due to slow 
    network functionalities, making the command <code>exist</code> , which is 
    used in <a href="#solvesdp">solvesdp</a> when detecting solvers, very slow.</p>
	<p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
	<p style="margin-bottom: 0; margin-top:0">Are you running over a network? 
	This can be extremely detrimental for general performance in YALMIP. On some 
	networked Linux version, YALMIP runs 10-100 times slower!</p>
	<p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
	<p style="margin-bottom: 0; margin-top:0">Do you have a poor sparse matrix 
	library in your installation? Some distributions seem to have extremely poor 
	performance for sparse matrices (observed on Linux), which is used a lot in YALMIP.&nbsp; One 
	way to test this is to run the script below. If the displayed result is 
	substantially larger than 20, you have problems (and I have no idea how you 
	can resolve this...)</p>
	<blockquote>
		<blockquote>
			<pre>d = sprandn(1e5,1,0.5);
tic;for i= 1:1000;d([2000:3000]);end;t1 = toc;
d = d';
tic;for i= 1:1000;d([2000:3000]);end;t2 = toc;t1/t2</pre>
		</blockquote>
	</blockquote>
    <p style="margin-bottom: 0; margin-top:0">Do 
    you have&nbsp;<a href="solvers.htm#mosek">MOSEK</a> installed? This solver overloads 
    the function <code>optimset</code> in Mathworks optimization toolbox, but is much slower. <code>optimset</code> is called in <a href="#sdpsettings">sdpsettings</a> 
    to initialize the option fields for <a href="solvers.htm#linprog">LINPROG</a> and
    <a href="solvers.htm#quadprog">QUADPROG</a>. Note that
    <a href="#sdpsettings">sdpsettings</a> is called in <a href="#solvesdp">solvesdp</a> 
    if no options structure is passed in the call. Hence, for optimal speed, 
    define the options structure once, and always use three arguments when 
    calling <a href="#solvesdp">solvesdp</a>. This is recommended even if you do 
    not have <a href="solvers.htm#mosek">MOSEK</a>.</p>
    <p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
    <p style="margin-bottom: 0; margin-top:0">Are you working with nonlinear 
    expressions? In that case, clear the internals of YALMIP regularly using
    <code>yalmip('clear')</code>.</p>
	<p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
    <p style="margin-bottom: 0; margin-top:0">Are you working with large 
	polynomial 
    expressions? Try to compile the file findhash.c (<code>mex findhash.c</code>)</p>
	<p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
    <p style="margin-bottom: 0; margin-top:0">Finally, standard MATLAB coding 
    practice applies. This means that you should try to vectorize code, define 
    things once etc.</p>
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    <hr noShade SIZE="1" color="#FF0000">        
    <p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
    <table border="0" cellpadding="0" style="border-collapse: collapse" width="100%">
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><b><font color="#0000FF">
        <a name="nosolver"></a>Q:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0"><b>YALMIP cannot find any 
        solver.</b></td>
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><font color="#0000FF"><b>A</b></font><b><font color="#0000FF">:</font></b></td>
        <td>
    <p style="margin-bottom: 0; margin-top:0">Do you have any solver? You typically 
    need to install a (or several) solver and update you path. See
    <a target="topic" href="solvers.htm">interfaced solver</a>.</p>
        </td>
      </tr>
    </table>
    <p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
    <table border="0" cellpadding="0" style="border-collapse: collapse" width="100%">
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><b><font color="#0000FF">
        <a name="penbmi update"></a>Q:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0"><b><a href="solvers.htm#penbmi">
        PENBMI</a> does not work with 
    YALMIP anymore.</b></td>
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><font color="#0000FF"><b>A</b></font><b><font color="#0000FF">:</font></b></td>
        <td>
    <p style="margin-bottom: 0; margin-top:0">Version 1.1 and earlier will not 
    work directly anymore. However, this is easily fixed. Edit the file 
    callpenbmim.m (if you use the
    <a target="_blank" href="http://www.penopt.com">PENOPT</a> version) or 
    callpenbmi.m (if you use the <a target="_blank" href="http://tomlab.biz">TOMLAB</a> 
    version). Uncomment the code below the comment &quot;UNCOMMENT THIS&quot;.</p>
        </td>
      </tr>
    </table>
    <p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
    <table border="0" cellpadding="0" style="border-collapse: collapse" width="100%">
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><b><font color="#0000FF">
        <a name="compile sdpt"></a>Q:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0"><b><a href="solvers.htm#sdpt3">SDPT3</a>-3.02 does not work with 
    YALMIP anymore.</b></td>
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><font color="#0000FF"><b>A</b></font><b><font color="#0000FF">:</font></b></td>
        <td>
    <p style="margin-bottom: 0; margin-top:0">Download <a href="solvers.htm#sdpt3">SDPT3</a>-3.02 and compile (code 
    updated without version increment)</p>
        </td>
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    </table>
    <p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
    <table border="0" cellpadding="0" style="border-collapse: collapse" width="100%">
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><b><font color="#0000FF">
        <a name="compile sdpt0"></a>Q:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0"><b>My version of
    <a href="solvers.htm#sdpt3">SDPT3</a>-3.02 does not work and complains about 
        the file <code>svec</code>.</b></td>
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><font color="#0000FF"><b>A</b></font><b><font color="#0000FF">:</font></b></td>
        <td>
    <p style="margin-bottom: 0; margin-top:0">Do you have the solver SDPPACK 
    installed? Remove the path to this solver.</p>
        </td>
      </tr>
    </table>
    <p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
    <table border="0" cellpadding="0" style="border-collapse: collapse" width="100%">
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><b><font color="#0000FF">
        <a name="sedumisdpt3"></a>Q:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0"> <b> <a href="solvers.htm#sdpt3">SDPT3</a> (or 
    <a href="solvers.htm#sedumi">SeDuMi</a>) does not work<font color="#0000FF">.</font></b></td>
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><font color="#0000FF"><b>A</b></font><b><font color="#0000FF">:</font></b></td>
        <td>
    <p style="margin-bottom: 0; margin-top:0">Make sure not to have both <a href="solvers.htm#sdpt3">SDPT3</a> 
    (version 3.02) and 
    <a href="solvers.htm#sedumi">SeDuMi</a> on the MATLAB path. This problem is 
    resolved in <a href="solvers.htm#sdpt3">SDPT3</a> 3.1</p>
        </td>
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    </table>
    <p style="margin-bottom: 0; margin-top:0">&nbsp;</p>
    <table border="0" cellpadding="0" style="border-collapse: collapse" width="100%">
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        <td width="26" valign="top">
        <p style="margin-bottom: 0; margin-top:0"><b><font color="#0000FF">
        <a name="csdppath"></a>Q:</font></b></td>
        <td>
        <p style="margin-bottom: 0; margin-top:0"> <b> <a href="solvers.htm#csdp">CSDP</a> does not work<font color="#0000FF">.</font></b></td>
      </tr>
      <tr>