AbsorptionLorentz¶
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class
sherpa.astro.optical.
AbsorptionLorentz
(name='absorptionlorentz')[source] [edit on github]¶ Bases:
sherpa.models.model.RegriddableModel1D
Lorentz function for modeling absorption (equivalent width).
This model is intended to be used to modify another model (e.g. by multiplying the two together). It is for use when the independent axis is in Angstroms.
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fwhm
¶ The full-width half-maximum of the model in km/s.
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pos
¶ The center of the lorentzian, in Angstroms.
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ewidth
¶ The equivalent width of the model, in Angstroms.
Notes
The functional form of the model for points is:
f(x) = 1 - ewidth * c / (1.571 * fwhm * pos * l(x)) l(x) = 1 + 4 * ((1 / x - 1 / pos) * pos * c / fwhm)^2 c = speed of light in km/s
and for integrated data sets the low-edge of the grid is used.
The speed of light can be found by inspecting the module variable
sherpa.astro.optical.c_km
.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
(p, x[, xhi])Evaluate the model on a grid.
guess
(dep, *args, **kwargs)Set an initial guess for the parameter values.
regrid
(*args, **kwargs)The class RegriddableModel1D allows the user to evaluate in the requested space then interpolate onto the data space.
reset
()Reset the parameter values.
set_center
(*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
= 1¶
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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
(p, x, xhi=None, **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) [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]¶ The class RegriddableModel1D allows the user to evaluate in the requested space then interpolate onto the data space. An optional argument ‘interp’ enables the user to change the interpolation method.
Examples
>>> import numpy as np >>> from sherpa.models.basic import Box1D >>> mybox = Box1D() >>> request_space = np.arange(1, 10, 0.1) >>> regrid_model = mybox.regrid(request_space, interp=linear_interp)
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reset
() [edit on github]¶ Reset the parameter values.
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set_center
(*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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