LogParabola

class sherpa.models.basic.LogParabola(name='logparabola')

Bases: sherpa.models.model.RegriddableModel1D

One-dimensional log-parabolic function.

ref

The reference point for the normalization.

c1

The power-law index (gamma).

c2

The curvature of the parabola (beta).

ampl

The amplitude of the model.

See also

Exp, Exp10, Log, Log10, Sqrt

Notes

The functional form of the model for points is:

f(x) = ampl * (x / ref) ^ (-c1 - c2 * log_10 (x / ref))

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

[1]	https://www.gnu.org/software/gsl/manual/html_node/QNG-non_002dadaptive-Gauss_002dKronrod-integration.html

Attributes Summary

thawedparhardmaxes
thawedparhardmins
thawedparmaxes
thawedparmins
thawedpars

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)

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.

See also

teardown()

teardown()

Called after a model may be evaluated multiple times.

See also

setup()