Guess growth models parameters

Description

Guess initial parameters values for growth models

Usage

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

Arguments

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.

Value

A list with entries:

Author(s)

Julien Gagneur

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")

Results

R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
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Type 'license()' or 'licence()' for distribution details.

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'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library(cellGrowth)
Loading required package: locfit
locfit 1.5-9.1 	 2013-03-22
> png(filename="/home/ddbj/snapshot/RGM3/R_BC/result/cellGrowth/guessCellGrowthParams.Rd_%03d_medium.png", width=480, height=480)
> ### Name: guessCellGrowthParams
> ### Title: Guess growth models parameters
> ### Aliases: guessCellGrowthParams
> 
> ### ** 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")
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>