SSexp: Self-Starting Nls exponential regression model

Description Usage Arguments Format Value Author(s) Examples

Description

This selfStart model evaluates the exponential growth regression model and its gradient. It has an initial attribute that will evaluate initial estimates of the parameters y0, and b for a given set of data. Instead of the standard exp function this implementation use the 10^ function.

f(x)=y_0 \times 10^b

Usage

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SSexp(x, b, y0)

Arguments

x

a numeric vector of values at which to evaluate the model

b

a numeric parameter representing the growth rate

y0

a numeric parameter representing the value of the response when x is 0

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)$plate_1

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

summary(ig)

Example output

  analyte        b        c obs   rsquare convergence   fct
1     FGF 8.181471 1.441658  17 0.9261425 convergence SSexp

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