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

NAME
       PDL::Fit::Gaussian - routines for fitting gaussians

DESCRIPTION
       This module contains some custom	gaussian fitting routines.  These were
       developed in collaboration with Alison Offer, they do a reasonably
       robust job and are quite	useful.

       Gaussian	fitting	is something I do a lot	of, so I figured it was	worth
       putting in my special code.

       Note it is not clear to me that this code is fully debugged. The	reason
       I say that is because I tried using the internal	linear eqn solving C
       routines	called elsewhere and they were giving erroneous	results.  So
       steal from this code with caution! However it does give good fits to
       reasonable looking gaussians and	tests show correct parameters.

		    KGB	29/Oct/2002

SYNOPSIS
	       use PDL;
	       use PDL::Fit::Gaussian;
	       ($cen, $pk, $fwhm, $back, $err, $fit) = fitgauss1d($x, $data);
	       ($pk, $fwhm, $back, $err, $fit) = fitgauss1dr($r, $data);

FUNCTIONS
   fitgauss1d
       Fit 1D Gassian to data piddle

	 ($cen,	$pk, $fwhm, $back, $err, $fit) = fitgauss1d($x,	$data);

	 ($cen,	$pk, $fwhm, $back, $err, $fit) = fitgauss1d($x,	$data);

	 xval(n); data(n); [o]xcentre();[o]peak_ht(); [o]fwhm();
	 [o]background();int [o]err(); [o]datafit(n);
	 [t]sig(n);  [t]xtmp(n); [t]ytmp(n); [t]yytmp(n); [t]rtmp(n);

       Fits a 1D Gaussian robustly free	parameters are the centre, peak
       height, FWHM. The background is NOT fit,	because	I find this is
       generally unreliable, rather a median is	determined in the 'outer' 10%
       of pixels (i.e. those at	the start/end of the data piddle). The initial
       estimate	of the FWHM is the length of the piddle/3, so it might fail if
       the piddle is too long. (This is	non-robust anyway). Most data does
       just fine and this is a good default gaussian fitter.

       SEE ALSO: fitgauss1dr() for fitting radial gaussians

   fitgauss1dr
       Fit 1D Gassian to radial	data piddle

	 ($pk, $fwhm2, $back, $err, $fit) = fitgauss1dr($r, $data);

	 ($pk, $fwhm2, $back, $err, $fit) = fitgauss1dr($r, $data);

	 xval(n); data(n); [o]peak_ht(); [o]fwhm();
	 [o]background();int [o]err(); [o]datafit(n);
	 [t]sig(n);  [t]xtmp(n); [t]ytmp(n); [t]yytmp(n); [t]rtmp(n);

       Fits a 1D radial	Gaussian robustly free parameters are the peak height,
       FWHM. Centre is assumed to be X=0 (i.e. start of	piddle).  The
       background is NOT fit, because I	find this is generally unreliable,
       rather a	median is determined in	the 'outer' 10%	of pixels (i.e.	those
       at the end of the data piddle). The initial estimate of the FWHM	is the
       length of the piddle/3, so it might fail	if the piddle is too long.
       (This is	non-robust anyway). Most data does just	fine and this is a
       good default gaussian fitter.

       SEE ALSO: fitgauss1d() to fit centre as well.

BUGS
       May not converge	for weird data,	still pretty good!

AUTHOR
       This file copyright (C) 1999, Karl Glazebrook (kgb@aaoepp.aao.gov.au),
       Gaussian	fitting	code by	Alison Offer (aro@aaocbn.aao.gov.au).  All
       rights reserved.	There is no warranty. You are allowed to redistribute
       this software / documentation under certain conditions. For details,
       see the file COPYING in the PDL distribution. If	this file is separated
       from the	PDL distribution, the copyright	notice should be included in
       the file.

perl v5.32.0			  2020-08-09			   Gaussian(3)

NAME | DESCRIPTION | SYNOPSIS | FUNCTIONS | BUGS | AUTHOR

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