Last modified: December 2018

URL: http://cxc.harvard.edu/sherpa/ahelp/normbeta1d.html
AHELP for CIAO 4.11 Sherpa v1

normbeta1d

Context: models

Synopsis

One-dimensional normalized beta model function.

Syntax

normbeta1d

Description

This is the same model as the Beta1D model but with a different slope parameter and normalisation.


Example

>>> create_model_component("normbeta1d", "mdl")
>>> print(mdl)

Create a component of the normbeta1d model and display its default parameters. The output is:

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.pos      thawed            0 -3.40282e+38  3.40282e+38           
   mdl.width    thawed            1  1.17549e-38  3.40282e+38           
   mdl.index    thawed          2.5          0.5         1000           
   mdl.ampl     thawed            1            0  3.40282e+38           

ATTRIBUTES

The attributes for this object are:

pos

The center of the line.

w

The line width.

alpha

The slope of the profile at large radii.

ampl

The amplitude refers to the integral of the model.

Notes

The functional form of the model for points is:

f(x) = A * (1 + ((x - pos) / w)^2)^(-alpha)

   A = ampl / integral f(x) dx

The grid version is evaluated by numerically intgerating the function over each bin using a non-adaptive Gauss-Kronrod scheme suited for smooth functions [1] , falling over to a simple trapezoid scheme if this fails.

References


Bugs

See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.

See Also

models
beta1d, lorentz1d