* Bug #8395 fixed - dft has been deprecated to fft.
[scilab.git] / scilab / modules / signal_processing / help / en_US / transforms / dft.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" xmlns:scilab="http://www.scilab.org" xml:lang="en" xml:id="dft">
3     <refnamediv>
4         <refname>dft (deprecated)</refname>
5         <refpurpose>discrete Fourier transform
6             <emphasis role="bold">This function is obsolete.</emphasis>
7         </refpurpose>
8     </refnamediv>
9     <refsynopsisdiv>
10         <title>Calling Sequence</title>
11         <synopsis>[xf]=dft(x,flag);</synopsis>
12     </refsynopsisdiv>
13     <refsection>
14         <title>Arguments</title>
15         <variablelist>
16             <varlistentry>
17                 <term>x</term>
18                 <listitem>
19                     <para>input vector</para>
20                 </listitem>
21             </varlistentry>
22             <varlistentry>
23                 <term>flag</term>
24                 <listitem>
25                     <para>indicates dft (flag=-1)  or idft (flag=1)</para>
26                 </listitem>
27             </varlistentry>
28             <varlistentry>
29                 <term>xf</term>
30                 <listitem>
31                     <para>output vector</para>
32                 </listitem>
33             </varlistentry>
34         </variablelist>
35     </refsection>
36     <refsection>
37         <title>Description</title>
38         <para>
39             Function which computes dft of vector <literal>x</literal>.
40         </para>
41     </refsection>
42     <refsection>
43         <title>Examples</title>
44         <programlisting role="example"><![CDATA[ 
45 n=8;omega = exp(-2*%pi*%i/n);
46 j=0:n-1;F=omega.^(j'*j);  //Fourier matrix
47 x=1:8;x=x(:);
48 F*x
49 fft(x,-1)
50 dft(x,-1)
51 inv(F)*x
52 fft(x,1)
53 dft(x,1)
54  ]]></programlisting>
55     </refsection>
56     
57     <refsection>
58         <title>History</title>
59         <revhistory>
60             <revision>
61                 <revnumber>5.4.1</revnumber>
62                 <revremark>
63                     dft is obsolete. The algorithm has been moved to the <link linkend="fft">fft</link> help page.
64                 </revremark>
65             </revision>
66         </revhistory>
67     </refsection>
68     
69     <refsection role="see also">
70         <title>See Also</title>
71         <simplelist type="inline">
72             <member>
73                 <link linkend="fft">fft</link>
74             </member>
75         </simplelist>
76     </refsection>
77 </refentry>