SigmaGauss2D¶
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class
sherpa.models.basic.
SigmaGauss2D
(name='sigmagauss2d')[source] [edit on github]¶ Bases:
sherpa.models.basic.Gauss2D
Two-dimensional gaussian function (varying sigma).
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sigma_a
¶ The sigma of the gaussian along the major axis.
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sigma_b
¶ The sigma of the gaussian along the minor axis.
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xpos
¶ The center of the gaussian on the x0 axis.
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ypos
¶ The center of the gaussian on the x1 axis.
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theta
¶ The angle of the major axis. It is in radians, measured counter-clockwise from the X0 axis (i.e. the line X1=0).
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ampl
¶ The amplitude refers to the maximum peak of the model.
See also
Notes
The functional form of the model for points is:
f(x0,x1) = ampl * exp(-r(x0,x1)^2 / 2) r(x0,x1)^2 = xoff(x0,x1)^2 + yoff(x0,x1)^2 ------------- ------------- sigma_a^2 sigma_b^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
The hard maximum values for the thawed parameters.
The hard minimum values for the thawed parameters.
Access to the maximum limits for the thawed parameters
Access to the minimum limits for the thawed parameters
Access to the thawed parameters of the model
Methods Summary
apply
(outer, *otherargs, **otherkwargs)calc
(*args, **kwargs)Evaluate the model on a grid.
guess
(dep, *args, **kwargs)Set an initial guess for the parameter values.
regrid
(*args, **kwargs)reset
()Reset the parameter values.
set_center
(xpos, ypos, *args, **kwargs)startup
([cache])Called before a model may be evaluated multiple times.
teardown
()Called after a model may be evaluated multiple times.
Attributes Documentation
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ndim
= 2¶
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thawedparhardmaxes
¶ The hard maximum values for the thawed parameters.
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thawedparhardmins
¶ The hard minimum values for the thawed parameters.
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thawedparmaxes
¶ Access to the maximum limits for the thawed parameters
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thawedparmins
¶ Access to the minimum limits for the thawed parameters
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thawedpars
¶ Access to the thawed parameters of the model
Methods Documentation
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apply
(outer, *otherargs, **otherkwargs) [edit on github]¶
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calc
(*args, **kwargs)[source] [edit on github]¶ Evaluate the model on a grid.
- Parameters
p (sequence of numbers) – The parameter values to use. The order matches the
pars
field.*args – The model grid. The values can be scalar or arrays, and the number depends on the dimensionality of the model and whether it is being evaluated over an integrated grid or at a point (or points).
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get_center
() [edit on github]¶
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guess
(dep, *args, **kwargs)[source] [edit on github]¶ Set an initial guess for the parameter values.
Attempt to set the parameter values, and ranges, for the model to match the data values. This is intended as a rough guess, so it is expected that the model is only evaluated a small number of times, if at all.
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regrid
(*args, **kwargs) [edit on github]¶
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reset
() [edit on github]¶ Reset the parameter values.
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set_center
(xpos, ypos, *args, **kwargs) [edit on github]¶
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startup
(cache=False) [edit on github]¶ Called before a model may be evaluated multiple times.
- Parameters
cache (bool, optional) – Should a cache be used when evaluating the models.
See also
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teardown
() [edit on github]¶ Called after a model may be evaluated multiple times.
See also
setup()
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