dd_skewgauss

Skew Gaussian distribution parametric model

Syntax

info = dd_skewgauss()
P = dd_skewgauss(r,param)
Parameters
  • r - Distance axis (N-array)
  • param - Model parameters
Returns
  • P - Distance distribution (N-array)
  • info - Model information (struct)

Model

../_images/model_scheme_dd_skewgauss.png

P(r) = \sqrt{\frac{2}{\pi}}\frac{1}{\sigma}\exp\left(-\frac{(r-\left<r\right>)^2}{\sqrt(2)\sigma^2}\right)\frac{1}{2}\left(1 + erf\left(\frac{(r-\left<r\right>)}{\sqrt{2}\sigma}\right) \right)

with \sigma = w/(2\sqrt{2ln(2)})

Variable Symbol Default Lower bound Upper bound Description
param(1) r_0 3.5 1.0 20 Center distance (nm)
param(2) w 0.5 0.2 5 FWHM (nm)
param(2) \alpha 5.0 -15 15 Skewness

Example using default parameters:

../_images/model_dd_skewgauss.png

Description

info = dd_skewgauss()

Returns an info structure containing the specifics of the model:

  • info.model - Full name of the parametric model.
  • info.nparam - Total number of adjustable parameters.
  • info.parameters - Structure array with information on individual parameters.
P = dd_skewgauss(r,param)

Computes the distance distribution model P from the axis r according to the parameters array param. The required parameters can also be found in the info structure.