28.1.106 Logistpk


Function

y=y_0+\frac{4Ae^{-\frac{x-xc}w}}{\left( 1+e^{-\frac{x-xc}w}\right) ^2}

Brief Description

Logistic peak function, also called Hubbert function.

Sample Curve

CFF Image312.jpg

Parameters

Number: 4

Names: y0, xc, w, A

Meanings: y0 = offset, xc = center, w = width, A = amplitude

Lower Bounds: w > 0.0

Upper Bounds: none

Derived Parameters

Full Width at Half Maximum: FWHM = w * ( ln(3 + 2 * sqrt(2)) - ln(3 - 2 * sqrt(2)) )

Script Access

nlf_logistpk(x,y0,xc,w,A)

Function File

FITFUNC\LOGISTPK

Category

Origin Basic Functions, Growth/Sigmoidal, Peak Functions