* Bug #11670 to 11676 fixed - Add examples in the signal processing help pages.
[scilab.git] / scilab / modules / signal_processing / help / en_US / mfft.xml
1 <?xml version="1.0" encoding="UTF-8"?>
2 <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="mfft">
3     <refnamediv>
4         <refname>mfft</refname>
5         <refpurpose> multi-dimensional fft</refpurpose>
6     </refnamediv>
7     <refsynopsisdiv>
8         <title>Calling Sequence</title>
9         <synopsis>[xk]=mfft(x,flag,dim)</synopsis>
10     </refsynopsisdiv>
11     <refsection>
12         <title>Arguments</title>
13         <variablelist>
14             <varlistentry>
15                 <term>x</term>
16                 <listitem>
17                     <para>
18                         <literal>x(i,j,k,...)</literal> input signal in the form of a row vector whose values are arranged so that the i index runs the quickest, followed by the j index, etc.
19                     </para>
20                 </listitem>
21             </varlistentry>
22             <varlistentry>
23                 <term>flag</term>
24                 <listitem>
25                     <para>(-1) FFT or (1) inverse FFT</para>
26                 </listitem>
27             </varlistentry>
28             <varlistentry>
29                 <term>dim</term>
30                 <listitem>
31                     <para>
32                         dimension vector which gives the number of values of <literal>x</literal> for each of its indices
33                     </para>
34                 </listitem>
35             </varlistentry>
36             <varlistentry>
37                 <term>xk</term>
38                 <listitem>
39                     <para>
40                         output of multidimensional fft in same format as for <literal>x</literal>
41                     </para>
42                 </listitem>
43             </varlistentry>
44         </variablelist>
45     </refsection>
46     <refsection>
47         <title>Description</title>
48         <para>
49             FFT for a multi-dimensional signal
50         </para>
51         <para>
52             For example for a three dimensional vector which has three points
53             along its first dimension, two points along its second
54             dimension and three points along its third dimension the row
55             vector is arranged as follows
56         </para>
57         <programlisting role="no-scilab-exec"><![CDATA[ 
58 x=[x(1,1,1),x(2,1,1),x(3,1,1),
59    x(1,2,1),x(2,2,1),x(3,2,1),
60    x(1,1,2),x(2,1,2),x(3,1,2),
61    x(1,2,2),x(2,2,2),x(3,2,2),
62    x(1,1,3),x(2,1,3),x(3,1,3),
63    x(1,2,3),x(2,2,3),x(3,2,3)]
64  ]]></programlisting>
65         <para>
66             and the <literal>dim</literal> vector is: <literal>dim=[3,2,3]</literal>
67         </para>
68     </refsection>
69     <refsection>
70         <title>Examples</title>
71         <programlisting role="example"><![CDATA[ 
72 y1=matrix(1:6,2,3)
73 y2=matrix(7:12,2,3)
74 y=matrix([y1,y2],1,12)
75 yf=mfft(y,-1,[2 3 2])
76  ]]></programlisting>
77     </refsection>
78     
79 </refentry>