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<?xml version="1.0" encoding="UTF-8"?>
<!--
*
* This help file was generated from fft1.sci using help_from_sci().
*
-->
<refentry version="5.0-subset Scilab" xml:id="fft1" xml:lang="en"
xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:svg="http://www.w3.org/2000/svg"
xmlns:ns3="http://www.w3.org/1999/xhtml"
xmlns:mml="http://www.w3.org/1998/Math/MathML"
xmlns:scilab="http://www.scilab.org"
xmlns:db="http://docbook.org/ns/docbook">
<refnamediv>
<refname>fft1</refname>
<refpurpose>Calculates the discrete Fourier transform of a matrix using Fast Fourier Transform algorithm.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Calling Sequence</title>
<synopsis>
fft (x, n, dim)
fft (x, n)
fft (x)
</synopsis>
</refsynopsisdiv>
<refsection>
<title>Parameters</title>
<variablelist>
<varlistentry><term>x:</term>
<listitem><para> input matrix</para></listitem></varlistentry>
<varlistentry><term>n:</term>
<listitem><para> Specifies the number of elements of x to be used</para></listitem></varlistentry>
<varlistentry><term>dim:</term>
<listitem><para> Specifies the dimention of the matrix along which the FFT is performed</para></listitem></varlistentry>
</variablelist>
</refsection>
<refsection>
<title>Description</title>
<para>
This is an Octave function.
The FFT is calculated along the first non-singleton dimension of the array. Thus, FFT is computed for each column of x.
</para>
<para>
n is an integer specifying the number of elements of x to use. If n is larger than dimention along. which the FFT is calculated, then x is resized and padded with zeros.
Similarly, if n is smaller, then x is truncated.
</para>
<para>
dim is an integer specifying the dimension of the matrix along which the FFT is performed.
</para>
</refsection>
<refsection>
<title>Examples</title>
<programlisting role="example"><![CDATA[
x = [1 2 3; 4 5 6; 7 8 9]
n = 3
dim = 2
fft1 (x, n, dim)
ans =
6.0000 + 0.0000i -1.5000 + 0.8660i -1.5000 - 0.8660i
15.0000 + 0.0000i -1.5000 + 0.8660i -1.5000 - 0.8660i
24.0000 + 0.0000i -1.5000 + 0.8660i -1.5000 - 0.8660i
]]></programlisting>
</refsection>
</refentry>
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