# PowLaw1D¶

class sherpa.models.basic.PowLaw1D(name='powlaw1d')[source]

One-dimensional power-law function.

It is assumed that the independent axis is positive at all points.

gamma

The photon index of the power law.

ref

As the reference point is degenerate with the amplitude, the alwaysfrozen attribute of the reference point is set so that it can not be varied during a fit.

ampl

The amplitude of the model.

Notes

The functional form of the model for points is:

f(x) = ampl * (x / ref)^(-gamma)


and for an integrated grid it is the integral of this over the bin.

Attributes Summary

Methods Summary

 apply(outer, *otherargs, **otherkwargs) calc(pars, xlo, *args, **kwargs) get_center() guess(dep, *args, **kwargs) Set an initial guess for the parameter values. regrid(*arrays) reset() set_center(*args, **kwargs) startup() Called before a model may be evaluated multiple times. teardown() Called after a model may be evaluated multiple times.

Attributes Documentation

thawedparhardmaxes
thawedparhardmins
thawedparmaxes
thawedparmins
thawedpars

Methods Documentation

apply(outer, *otherargs, **otherkwargs)
calc(pars, xlo, *args, **kwargs)
get_center()
guess(dep, *args, **kwargs)[source]

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.

regrid(*arrays)
reset()
set_center(*args, **kwargs)
startup()

Called before a model may be evaluated multiple times.

teardown()

Called after a model may be evaluated multiple times.

setup()