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<head><title>QHULL: Compute the complex hull</title> 
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href="#tailmanualse143.html">Tail</a></td></tr></table><h3 class="sectionHead"><span class="titlemark">16.50    </span> <a 
 id="x209-77600016.50"></a>QHULL: Compute the complex hull</h3>
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<!--l. 860--><p class="noindent" >This package is an interface to qhull (<a 
href="www.qhull.org" class="url" ><span 
class="pcrr8t-x-x-109">www.qhull.org</span></a>), which has to be installed
externally. There are 3 options for this package to ﬁnd the qhull program:
     </p><ol  class="enumerate1" >
     <li 
  class="enumerate" id="x209-776004x1">Put it into the path of your shell (recommended).
     </li>
     <li 
  class="enumerate" id="x209-776006x2">Set and export an environment variable <span 
class="pcrr8t-x-x-109">QHULL </span>to the complete path, e.g., in the
     Bash:
                                                                     

                                                                     
     <div class="verbatim" id="verbatim-1167">
     export QHULL=/usr/bin/qhull
</div>
     <!--l. 868--><p class="nopar" >
     </p></li>
     <li 
  class="enumerate" id="x209-776008x3">Inside Reduce set the variable <span 
class="pcrr8t-x-x-109">qhull_call!* </span>to the complete path,
     e.g.,
                                                                     

                                                                     
     <div class="verbatim" id="verbatim-1168">
     symbolic(qhull_call!* := &#x0022;/usr/bin/qhull&#x0022;);
</div>
     <!--l. 872--><p class="nopar" ></p></li></ol>
<!--l. 874--><p class="noindent" >Example: Compute the convex hull of a list integer points as a subset of that list as
follows:
                                                                     

                                                                     
</p>
<div class="verbatim" id="verbatim-1169">
1: qhull {{2,0,0}, {0,2,0}, {0,2,2}, {0,0,0}, {1,1,1}};
 <br />
 <br />{{2,0,0},{0,2,0},{0,2,2},{0,0,0}}
 <br />
 <br />2: symbolic;
 <br />
 <br />nil
 <br />
 <br />3* qhull_qhull {{2,0,0}, {0,2,0}, {0,2,2}, {0,0,0}, {1,1,1}};
 <br />
 <br />((2 0 0) (0 2 0) (0 2 2) (0 0 0))
</div>
<!--l. 889--><p class="nopar" >
</p><!--l. 891--><p class="noindent" >Author: Thomas Sturm, March 2013
</p><!--l. 893--><p class="noindent" >
                                                                     

                                                                     
                                                                     

                                                                     
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