NormGauss2D

class sherpa.models.basic.NormGauss2D(name='normgauss2d')

Bases: sherpa.models.model.ArithmeticModel

Two-dimensional normalised gaussian function.

fwhm

The Full-Width Half Maximum of the gaussian along the major axis. It is related to the sigma value by: FWHM = sqrt(8 * log(2)) * sigma.

xpos

The center of the gaussian on the x0 axis.

ypos

The center of the gaussian on the x1 axis.

ellip

The ellipticity of the gaussian.

theta

The angle of the major axis. It is in radians, measured counter-clockwise from the X0 axis (i.e. the line X1=0).

ampl

The amplitude refers to the integral of the model over the range -infinity to infinity for both axes.

See also

Gauss2D, NormGauss1D, SigmaGauss2D

Notes

The functional form of the model for points is:

f(x0,x1) = 4 * log(2) * ampl * exp(-4 * log(2) * r(x0,x1)^2)
           -------------------------------------------------
               pi * fwhm * fwhm * sqrt(1 - ellip * ellip)

r(x0,x1)^2 = xoff(x0,x1)^2 * (1-ellip)^2 + yoff(x0,x1)^2
             -------------------------------------------
                         fwhm^2 * (1-ellip)^2

xoff(x0,x1) = (x0 - xpos) * cos(theta) + (x1 - ypos) * sin(theta)

yoff(x0,x1) = (x1 - ypos) * cos(theta) - (x0 - xpos) * sin(theta)

The grid version is evaluated by adaptive multidimensional integration scheme on hypercubes using cubature rules, based on code from HIntLib ([1]) and GSL ([2]).

References

[1]	HIntLib - High-dimensional Integration Library http://mint.sbg.ac.at/HIntLib/

[2]	GSL - GNU Scientific Library http://www.gnu.org/software/gsl/

Attributes Summary

thawedparhardmaxes
thawedparhardmins
thawedparmaxes
thawedparmins
thawedpars

Methods Summary

apply(outer, \*otherargs, \*\*otherkwargs)
calc(\*args, \*\*kwargs)
get_center()
guess(dep, \*args, \*\*kwargs)
reset()
set_center(xpos, ypos, \*args, \*\*kwargs)
startup()
teardown()

Attributes Documentation

thawedparhardmaxes

thawedparhardmins

thawedparmaxes

thawedparmins

thawedpars

Methods Documentation

apply(outer, *otherargs, **otherkwargs)

calc(*args, **kwargs)

get_center()

guess(dep, *args, **kwargs)

reset()

set_center(xpos, ypos, *args, **kwargs)

startup()

teardown()