Commit 57199184 authored by Andreas J. Guelzow's avatar Andreas J. Guelzow Committed by Andreas J. Guelzow

document Fourier Analysis Tool. new

2002-01-11 Andreas J. Guelzow <aguelzow@taliesin.ca>

	* analysis-tools.sgml : document Fourier Analysis Tool.
	* doc/C/figures/analysistools-fourier-formula.png : new
parent 25051821
2002-01-11 Andreas J. Guelzow <aguelzow@taliesin.ca>
* analysis-tools.sgml : document Fourier Analysis Tool.
* doc/C/figures/analysistools-fourier-formula.png : new
2002-01-11 Andreas J. Guelzow <aguelzow@taliesin.ca>
* analysis-tools.sgml : update histogram documentation
......
2002-01-11 Andreas J. Guelzow <aguelzow@taliesin.ca>
* analysis-tools.sgml : document Fourier Analysis Tool.
* doc/C/figures/analysistools-fourier-formula.png : new
2002-01-11 Andreas J. Guelzow <aguelzow@taliesin.ca>
* analysis-tools.sgml : update histogram documentation
......
......@@ -454,7 +454,50 @@
<sect1 id="fourier-analysis-tool">
<title>Fourier Analysis Tool</title>
<para>This tool is not yet implemented.</para>
<figure id="fourier-tool-dialog">
<title>Fourier Analysis Tool Dialog</title>
<screenshot>
<graphic fileref="figures/analysistools-fourier.png" format="PNG"></graphic>
</screenshot>
</figure>
<para>The Fourier Analysis tool normally performs a Fast Fourier Transform to obtain the
discrete fourier transform <parameter>F<subscript>s</subscript></parameter> of the given
sequence <parameter>f<subscript>t</subscript></parameter> of real numbers according to
the formula given in <xref linkend="fourier-tool-formula">.</para>
<para>Select the <quote><guilabel>Inverse</guilabel></quote> option to calculate the
inverse discrete fourier transform <parameter>f<subscript>t</subscript></parameter>
of the given sequence <parameter>F<subscript>s</subscript></parameter> of real
numbers</para>
<note><para>If the given sequences does not contain a number of terms that is a power
of 2 (i.e.
2, 4, 8, 16, 32, 64, 128, etc.), this tool will append zeros to reach such a power of
2!</para></note>
<para>Specify the cells containing the datasets in the <quote><guilabel>Input
Range</guilabel></quote> entry. The entered range or ranges are grouped into
sequences either by rows or by columns.</para>
<para>If you have labels
in the first cell of each data set, select the
<quote><guilabel>Labels</guilabel></quote> option.</para>
<figure id="fourier-tool-formula">
<title>Fourier Analysis Formulae</title>
<screenshot>
<graphic fileref="figures/analysistools-fourier-formula.png" format="PNG"></graphic>
</screenshot>
</figure>
<note><para>Before using the numbers obtained by this tool, ensure that these are in fact the
correct formulae for your discipline. In the physical sciences this fourier transform tends
to be called the inverse fourier transform and vice versa. Moreover, frequently the scaling
factor varies.</para>
<para>For example <application>Mathematica</application> uses the terms fourier
transform and inverse fourier transform with the reversed meaning than
<application>Gnumeric</application> and it uses a scaling factor of
<parameter>1/SQRT(N)</parameter> rather than <parameter>1/N</parameter>.</para></note>
</sect1>
<sect1 id="ftest-two-sample-for-variances-tool">
......
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