Synopsis
One-dimensional broken power-law function.
Syntax
bpl1d
Example
>>> create_model_component("bpl1d", "mdl")
>>> print(mdl)Create a component of the bpl1d model and display its default parameters. The output is:
mdl Param Type Value Min Max Units ----- ---- ----- --- --- ----- mdl.gamma1 thawed 0 -10 10 mdl.gamma2 thawed 0 -10 10 mdl.eb thawed 100 0 1000 mdl.ref frozen 1 -3.40282e+38 3.40282e+38 mdl.ampl thawed 1 1e-20 3.40282e+38
ATTRIBUTES
The attributes for this object are:
| Attribute | Definition |
|---|---|
| gamma1 | The slope of the power law below the break point. |
| gamma2 | The slope of the power law above the break point. |
| eb | The position of the break point. |
| ref | The reference position for the amplitude. |
| ampl | The amplitude, defined with respect to the reference position. |
Notes
The functional form of the model for points is:
f(x) = ampl * (x / ref)^(-gamma1) x <= eb
= ampl' * (x / ref)^(-gamma2) otherwise
ampl' = ampl (eb / ref)^(gamma2 - gamma1)and for an integrated grid it is the integral of this over the bin.
Bugs
See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.