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<?xml version="1.0" encoding="UTF-8"?>
<!--
*
* This help file was generated from goertzel.sci using help_from_sci().
*
-->
<refentry version="5.0-subset Scilab" xml:id="goertzel" xml:lang="en"
xmlns="http://docbook.org/ns/docbook"
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<refnamediv>
<refname>goertzel</refname>
<refpurpose>Computes DFT using the second order Goertzel Algorithm</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Calling Sequence</title>
<synopsis>
Y = goertzel(X,INDVEC,DIM)
</synopsis>
</refsynopsisdiv>
<refsection>
<title>Parameters</title>
<variablelist>
</variablelist>
</refsection>
<refsection>
<title>Description</title>
<para>
goertzel(X,INDVEC)
Computes the DFT of X at indices INDVEC using the second order algorithm along
the first non-singleton dimension. Elements of INDVEC must be positive integers
less than the length of the first non-singleton dimension. If INDVEC is empty
the DFT is computed at all indices along the first non-singleton dimension
goertzel(X,INDVEC,DIM)
Implements the algorithm along dimension DIM
In general goertzel is slower than fft when computing the DFT for all indices
along a particular dimension. However it is computationally more efficient when
the DFT at only a subset of indices is desired
Example
x=rand(1,5)
x =
</para>
<para>
0.6283918 0.8497452 0.6857310 0.8782165 0.0683740
y=goertzel(x,2);
y =
</para>
<para>
- 0.3531539 - 0.6299881i
Author
Ankur Mallick
References
Goertzel, G. (January 1958), "An Algorithm for the Evaluation of Finite Trigonometric Series", American Mathematical Monthly 65 (1): 34–35, doi:10.2307/2310304
</para>
</refsection>
</refentry>
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