SSl5: Self-Starting Nls 5 parameters logistic regression model

Description Usage Arguments Format Value Author(s) Examples

Description

This selfStart model evaluates the 5 parameters logistic regression model and its gradient. It has an initial attribute that will evaluate initial estimates of the parameters hAsym, lAsym, Slope, xMid and Asymetry for a given set of data Instead of the standard exp function this implementation use the 10^ function.

f(x)=lAsym +\frac{hAsym-lAsym}{(1+10^{Slope(x-xMid)})^{Asymetry}}

Usage

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SSl5(x, Slope, lAsym, hAsym, xMid, Asymetry)

Arguments

x

a numeric vector of values at which to evaluate the model

Slope

is a numeric parameter representing the -slope of the function at the inflection point

lAsym

a numeric parameter representing the lower asymptote when x trend to -Inf

hAsym

a numeric parameter representing the higher asymptote when x trend to Inf

xMid

is the x value corresponding to the inflection point

Asymetry

is a numeric parameter representing the asymetry around the inflection point

Format

A selfStart model

Value

The value returned is a list containing the nonlinear function, the self starter function and the parameter names.

Author(s)

John Aponte <[email protected]>

Examples

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# Load data
data(ecdata)
data(mfidata)

# Select analyte FGF for plate 1
dat <- mfidata[mfidata$plate=="plate_1" & mfidata$analyte=="FGF",]

sdf <- data_selection(dat, ecdata)[[1]]

# SSl5
ig <- scluminex("plate_1",sdf$standard, sdf$background,
            lfct="SSl5",
            bkg="ignore",
            fmfi="mfi",
            verbose=FALSE)

summary(ig)

Example output

  analyte          b        c        d        e        f obs   rsquare
1     FGF -0.8828771 1.306848 3.683054 1.389077 1.767844  17 0.9986956
  convergence  fct
1 convergence SSl5

drLumi documentation built on May 30, 2017, 5:47 a.m.