1
<?xml version="1.0" encoding="UTF-8"?>
3
* Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
4
* Copyright (C) 2008 - INRIA
6
* This file must be used under the terms of the CeCILL.
7
* This source file is licensed as described in the file COPYING, which
8
* you should have received as part of this distribution. The terms
9
* are also available at
10
* http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
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" version="5.0-subset Scilab" xml:lang="en" xml:id="projspec">
15
<refname>projspec</refname>
16
<refpurpose> spectral operators</refpurpose>
19
<title>Calling Sequence</title>
20
<synopsis>[S,P,D,i]=projspec(A)</synopsis>
23
<title>Arguments</title>
28
<para>square matrix</para>
34
<para>square matrices</para>
41
integer (index of the zero eigenvalue of <literal>A</literal>).
48
<title>Description</title>
50
Spectral characteristics of <literal>A</literal> at 0.
53
<literal>S</literal> = reduced resolvent at 0 (<literal>S</literal> = -Drazin_inverse(<literal>A</literal>)).
56
<literal>P</literal> = spectral projection at 0.
59
<literal>D</literal> = nilpotent operator at 0.
62
<literal>index</literal> = index of the 0 eigenvalue.
65
One has <literal>(s*eye()-A)^(-1) = D^(i-1)/s^i +... + D/s^2 + P/s - S - s*S^2 -...</literal>
66
around the singularity s=0.
70
<title>Examples</title>
71
<programlisting role="example"><![CDATA[
72
deff('j=jdrn(n)','j=zeros(n,n);for k=1:n-1;j(k,k+1)=1;end')
73
A=sysdiag(jdrn(3),jdrn(2),rand(2,2));X=rand(7,7);
75
[S,P,D,index]=projspec(A);
76
index //size of J-block
77
trace(P) //sum of dimensions of J-blocks
82
<refsection role="see also">
83
<title>See Also</title>
84
<simplelist type="inline">
86
<link linkend="coff">coff</link>