scilab/modules/m2sci/help/en_US/m2sci_equivalents/e/eig.xml

   1 <?xml version="1.0" encoding="ISO-8859-1"?>
   2 <!--
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   4  * Copyright (C) 2009 - DIGITEO - Vincent COUVERT
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  13 <refentry xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:svg="http://www.w3.org/2000/svg" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:db="http://docbook.org/ns/docbook" xmlns:scilab="http://www.scilab.org" xml:id="m2sci_eig">
  14     <refnamediv>
  15         <refname>eig (Matlab function)</refname>
  16         <refpurpose>Find eigenvalues and eigenvectors</refpurpose>
  17     </refnamediv>
  18     <refsection>
  19         <title>Matlab/Scilab equivalent</title>
  20         <informaltable border="1" width="100%">
  21             <tr>
  22                 <td align="center">
  23                     <emphasis role="bold">Matlab</emphasis>
  24                 </td>
  25                 <td align="center">
  26                     <emphasis role="bold">Scilab</emphasis>
  27                 </td>
  28             </tr>
  29             <tr>
  30                 <td>
  31                     <programlisting role="example"><![CDATA[
  32 eig
  33 ]]></programlisting>
  34                 </td>
  35                 <td>
  36                     <programlisting role="example"><![CDATA[
  37 spec ; bdiag
  38 ]]></programlisting>
  39                 </td>
  40             </tr>
  41         </informaltable>
  42     </refsection>
  43     <refsection>
  44         <title>Particular cases</title>
  45         <variablelist>
  46             <varlistentry>
  47                 <term>eig(A)</term>
  48                 <listitem>
  49                     <para>Scilab equivalent for eig(A) is spec(A). Scilab eigenvector matrix can differ from Matlab one.</para>
  50                 </listitem>
  51             </varlistentry>
  52             <varlistentry>
  53                 <term>eig(A,'nobalance')</term>
  54                 <listitem>
  55                     <para>
  56                         There is no Scilab equivalent for <emphasis role="bold">"nobalance"</emphasis> option. See examples.
  57                     </para>
  58                 </listitem>
  59             </varlistentry>
  60             <varlistentry>
  61                 <term>eig(A,B,flag)</term>
  62                 <listitem>
  63                     <para>
  64                         There is no Scilab equivalent for <emphasis role="bold">flag</emphasis>.
  65                     </para>
  66                 </listitem>
  67             </varlistentry>
  68         </variablelist>
  69     </refsection>
  70     <refsection>
  71         <title>Additional Remarks</title>
  72         <para>
  73             <note>
  74                 If matrix <varname>B</varname> is nonsingular, the generalized eigenvalues can be computed
  75                 as the eigenvalues of the matrix <latex>B^{-1}A</latex> i.e. <code>d=spec(B^-1*A)</code>.
  76             </note>
  77         </para>
  78     </refsection>
  79
  80     <refsection>
  81         <title>Examples</title>
  82         <informaltable border="1" width="100%">
  83             <tr>
  84                 <td align="center">
  85                     <emphasis role="bold">Matlab</emphasis>
  86                 </td>
  87                 <td align="center">
  88                     <emphasis role="bold">Scilab</emphasis>
  89                 </td>
  90             </tr>
  91             <tr>
  92                 <td>
  93                     <programlisting role="example"><![CDATA[
  94 d = eig(A,'balance')
  95 [V,D] = eig(A,'balance')
  96 [V,D] = eig(A,'balance')
  97 d = eig(A,B)
  98 d = eig(A,B)
  99 d = eig(A,B)
 100 [V,D] = eig(A,B)
 101 ]]></programlisting>
 102                 </td>
 103                 <td>
 104                     <programlisting role="example"><![CDATA[
 105 d = spec(A)
 106 [D,V]=bdiag(A)
 107 [V,D] = spec(A)
 108 [al,be] = spec(A,B); d = al./be;
 109 d = spec(A,B)
 110 d = spec(inv(B)*A)
 111 [al,be,V] = spec(A,B); D = diag(al./be);
 112 ]]></programlisting>
 113                 </td>
 114             </tr>
 115         </informaltable>
 116     </refsection>
 117 </refentry>