BrokenPowerlaw¶

class sherpa.astro.optical.BrokenPowerlaw(name='brokenpowerlaw')[source]¶

Bases: sherpa.models.model.ArithmeticModel

Broken power-law model.

It is for use when the independent axis is in Angstroms.

refer¶: The reference point at which the amplitude is defined, with units of Angstroms.

ampl¶: The amplitude at the reference point.

index1¶: The index for the power law below the reference point.

index2¶: The index for the power law above the reference point.

See also

Polynomial, Powerlaw

Notes

The functional form of the model for points is:

f(x) = ampl * (x / refer)^index1      x < refer

     = ampl * (x / refer)^index2      x >= refer

and for integrated data sets the low-edge of the grid is used.

Attributes Summary

`thawedparhardmaxes`
`thawedparhardmins`
`thawedparmaxes`
`thawedparmins`
`thawedpars`

Methods Summary

`apply`(outer, \otherargs, \\*otherkwargs)
`calc`(p, x[, xhi])
`get_center`()
`guess`(dep, \args, \\*kwargs)	Set an initial guess for the parameter values.
`reset`()
`set_center`(\args, \\*kwargs)
`startup`()
`teardown`()

Attributes Documentation

thawedparhardmaxes¶

thawedparhardmins¶

thawedparmaxes¶

thawedparmins¶

thawedpars¶

Methods Documentation

apply(outer, *otherargs, **otherkwargs)¶

calc(p, x, xhi=None, **kwargs)[source]¶

get_center()¶

guess(dep, *args, **kwargs)¶

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.

reset()¶

set_center(*args, **kwargs)¶

startup()¶

teardown()¶