28.1.3 Asym2Sig

Function

y=y_0+A\frac 1{1+e^{-\frac{x-x_c+w_1/2}{w_2}}}(1-\frac 1{1+e^{-\frac{x-x_c-w_1/2}{w_3}}})

Brief Description

Asymmetric double Sigmoidal function.

Sample Curve

CFF Image012.jpg

Parameters

Number: 6

Names: y0, xc, A, w1, w2, w3

Meanings: y0 = offset, xc = center, A = amplitude, w1 = full width of half maximum, w2 = variance of low-energy side, w3 = variance of high-energy side.

Lower Bounds: w1 > 0.0, w2 > 0.0, w3 > 0.0

Upper Bounds: none

Script Access

nlf_asym2sig(x,y0,xc,A,w1,w2,w3)

Function File

FITFUNC\ASYMDBLS.FDF

Category

Peak Functions,Power,PFW