scippneutron.peaks.model.PseudoVoigtModel

class scippneutron.peaks.model.PseudoVoigtModel(*, prefix='')

A Pseudo-Voigt function.

The model implements

\[f(x; A, \mu, \sigma, \alpha) = \alpha L(x; A, \mu, \sigma) + (1-\alpha) G(x; A, \mu, \sigma_G)\]

where \(L\) is a Lorentzian and \(G\) is a Gaussian. \(\sigma_G\) is derived from \(\sigma\) such that \(L\) and \(G\) have the same FWHM.

It has parameters

• \(A\): 'amplitude'

• \(\mu\): 'loc'

• \(\sigma\): 'scale'

• \(\alpha\): 'fraction'

__init__(*, prefix='')

Initialize a base model.

Parameters:

• param_names – Names of parameters in arbitrary order. Does not include the prefix.

• prefix (str, default: '') – Prefix used for model parameters in all user-facing data.

Methods

__init__(*[, prefix])	Initialize a base model.
fwhm(params)	Compute full width at half maximum.
guess(data, *[, coord])	Roughly estimate the model parameters for given data.
with_prefix(prefix)	Return a copy of the model with a new prefix.

Attributes

param_bounds	Parameter bounds.
param_names	Parameter names including the prefix.
prefix	Prefix for parameter names.

fwhm(params)

Compute full width at half maximum.

Parameters:

params (dict[str, Variable]) – Parameter values for which to compute the FWHM.

Returns:

Variable – FWHM of the model at the given parameters.