embryogrowth (version 5.0)

dydt.Gompertz: Return the derivative of the Gompertz function

Description

Return the derivative of the Gompertz function dydt.Gompertz(t, size, parms)

Usage

dydt.Gompertz(t, size, parms)

Arguments

t

The time in any unit

size

The current size

parms

A vector with alpha and K values being c(alpha=x1, K=x2)

Value

• A list with the derivative

Details

dydt.Gompertz returns the derivative of the Gompertz function.

Examples

library(embryogrowth)
data(nest)
formated <- FormatNests(nest)
# The initial parameters value can be:
# "T12H", "DHA",  "DHH", "Rho25"
# Or
# "T12L", "DT", "DHA",  "DHH", "DHL", "Rho25"
x <- structure(c(118.768297442004, 475.750095909406, 306.243694918151,
116.055824800264), .Names = c("DHA", "DHH", "T12H", "Rho25"))
# pfixed <- c(K=82.33) or rK=82.33/39.33
pfixed <- c(rK=2.093313)
# K or rK are not used for dydt.linear or dydt.exponential
resultNest_4p <- searchR(parameters=x, fixed.parameters=pfixed,
	temperatures=formated, derivate=dydt.Gompertz, M0=1.7,
	test=c(Mean=39.33, SD=1.92), method = "BFGS", maxiter = 200)
data(resultNest_4p)