SSl5: Self-Starting Nls 5 parameters logistic regression model
In drLumi: Multiplex Immunoassays Data Analysis

Description Usage Arguments Format Value Author(s) Examples

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}}

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

`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

A selfStart model

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

John Aponte <john.aponte@cresib.cat>

# 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)

  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