cellGrowth (version 1.16.0)

guessCellGrowthParams: Guess growth models parameters

Description

Guess initial parameters values for growth models

Usage

guessCellGrowthParams(x, z, relative.height.at.lag = 0.1)

Arguments

x

numeric vector: time points

z

codenumeric vector: log(OD)

relative.height.at.lag

numeric scalar (see Details)

Value

A list with entries:

mu

numeric scalar: maximal growth rate parameter

l

numeric scalar: time lag parameter

z0

numeric scalar: minimal log(OD) parameter

zmax

numeric scalar: maximal log(OD) parameter

Details

The relative.height.at.lag parameter should be close to the relative height of the point, where the curve reaches its maximal slope. If the fitting fails, try to set this parameter to a different value.

Examples

x <- 1:1000
z <- gompertz(x, mu=0.01, l=200, z0=1, zmax=5)+rnorm(length(x),mean=0,sd=0.25)
guess <- guessCellGrowthParams(x,z,relative.height.at.lag=0.5)
fit <- nls(z~gompertz(x,mu,l,z0,zmax),start=guess)
	plot(x,z)
lines(x,predict(fit,x),lwd=2,col="red")