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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.

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.

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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