1Gaussian(3)           User Contributed Perl Documentation          Gaussian(3)
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NAME

6       PDL::Fit::Gaussian - routines for fitting gaussians
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DESCRIPTION

9       This module contains some custom gaussian fitting routines.  These were
10       developed in collaboration with Alison Offer, they do a reasonably
11       robust job and are quite useful.
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13       Gaussian fitting is something I do a lot of, so I figured it was worth
14       putting in my special code.
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16       Note it is not clear to me that this code is fully debugged. The reason
17       I say that is because I tried using the internal linear eqn solving C
18       routines called elsewhere and they were giving erroneous results.  So
19       steal from this code with caution! However it does give good fits to
20       reasonable looking gaussians and tests show correct parameters.
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22                    KGB 29/Oct/2002
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SYNOPSIS

25               use PDL;
26               use PDL::Fit::Gaussian;
27               ($cen, $pk, $fwhm, $back, $err, $fit) = fitgauss1d($x, $data);
28               ($pk, $fwhm, $back, $err, $fit) = fitgauss1dr($r, $data);
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FUNCTIONS

31   fitgauss1d
32       Fit 1D Gassian to data piddle
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34         ($cen, $pk, $fwhm, $back, $err, $fit) = fitgauss1d($x, $data);
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36         ($cen, $pk, $fwhm, $back, $err, $fit) = fitgauss1d($x, $data);
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38         xval(n); data(n); [o]xcentre();[o]peak_ht(); [o]fwhm();
39         [o]background();int [o]err(); [o]datafit(n);
40         [t]sig(n);  [t]xtmp(n); [t]ytmp(n); [t]yytmp(n); [t]rtmp(n);
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42       Fits a 1D Gaussian robustly free parameters are the centre, peak
43       height, FWHM. The background is NOT fit, because I find this is
44       generally unreliable, rather a median is determined in the 'outer' 10%
45       of pixels (i.e. those at the start/end of the data piddle). The initial
46       estimate of the FWHM is the length of the piddle/3, so it might fail if
47       the piddle is too long. (This is non-robust anyway). Most data does
48       just fine and this is a good default gaussian fitter.
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50       SEE ALSO: fitgauss1dr() for fitting radial gaussians
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52   fitgauss1dr
53       Fit 1D Gassian to radial data piddle
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55         ($pk, $fwhm2, $back, $err, $fit) = fitgauss1dr($r, $data);
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57         ($pk, $fwhm2, $back, $err, $fit) = fitgauss1dr($r, $data);
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59         xval(n); data(n); [o]peak_ht(); [o]fwhm();
60         [o]background();int [o]err(); [o]datafit(n);
61         [t]sig(n);  [t]xtmp(n); [t]ytmp(n); [t]yytmp(n); [t]rtmp(n);
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63       Fits a 1D radial Gaussian robustly free parameters are the peak height,
64       FWHM. Centre is assumed to be X=0 (i.e. start of piddle).  The
65       background is NOT fit, because I find this is generally unreliable,
66       rather a median is determined in the 'outer' 10% of pixels (i.e. those
67       at the end of the data piddle). The initial estimate of the FWHM is the
68       length of the piddle/3, so it might fail if the piddle is too long.
69       (This is non-robust anyway). Most data does just fine and this is a
70       good default gaussian fitter.
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72       SEE ALSO: fitgauss1d() to fit centre as well.
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BUGS

75       May not converge for weird data, still pretty good!
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AUTHOR

78       This file copyright (C) 1999, Karl Glazebrook (kgb@aaoepp.aao.gov.au),
79       Gaussian fitting code by Alison Offer (aro@aaocbn.aao.gov.au).  All
80       rights reserved. There is no warranty. You are allowed to redistribute
81       this software / documentation under certain conditions. For details,
82       see the file COPYING in the PDL distribution. If this file is separated
83       from the PDL distribution, the copyright notice should be included in
84       the file.
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88perl v5.28.1                      2019-02-14                       Gaussian(3)
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