ExponentialCutoffPowerLaw1D

class astropy.modeling.powerlaws.ExponentialCutoffPowerLaw1D(amplitude=1, x_0=1, alpha=1, x_cutoff=1, **kwargs)[source]

Bases: astropy.modeling.Fittable1DModel

One dimensional power law model with an exponential cutoff.

Parameters
amplitudefloat

Model amplitude

x_0float

Reference point

alphafloat

Power law index

x_cutofffloat

Cutoff point

Notes

Model formula (with \(A\) for amplitude and \(\alpha\) for alpha):

\[f(x) = A (x / x_0) ^ {-\alpha} \exp (-x / x_{cutoff})\]

Attributes Summary

alpha

amplitude

input_units

This property is used to indicate what units or sets of units the evaluate method expects, and returns a dictionary mapping inputs to units (or None if any units are accepted).

param_names

x_0

x_cutoff

Methods Summary

evaluate(x, amplitude, x_0, alpha, x_cutoff)

One dimensional exponential cutoff power law model function

fit_deriv(x, amplitude, x_0, alpha, x_cutoff)

One dimensional exponential cutoff power law derivative with respect to parameters

Attributes Documentation

alpha = Parameter('alpha', value=1.0)
amplitude = Parameter('amplitude', value=1.0)
input_units
param_names = ('amplitude', 'x_0', 'alpha', 'x_cutoff')
x_0 = Parameter('x_0', value=1.0)
x_cutoff = Parameter('x_cutoff', value=1.0)

Methods Documentation

static evaluate(x, amplitude, x_0, alpha, x_cutoff)[source]

One dimensional exponential cutoff power law model function

static fit_deriv(x, amplitude, x_0, alpha, x_cutoff)[source]

One dimensional exponential cutoff power law derivative with respect to parameters