First-order Compartment Model

Usage

SSfol(Dose, input, lKe, lKa, lCl)

Arguments

Dose a numeric value representing the initial dose.
input a numeric vector at which to evaluate the model.
lKe a numeric parameter representing the natural logarithm of the elimination rate constant.
lKe a numeric parameter representing the natural logarithm of the absorption rate constant.
lCl a numeric parameter representing the natural logarithm of the clearance.

Description

This selfStart model evaluates the first-order compartment function and its gradient. It has an initial attribute that will evaluate initial estimates of the parameters lKe, lKa, and lCl for a given set of data.

Value

a numeric vector of the same length as input. It is the value of the expression Dose*exp(lKe+lKa-lCl)*(exp(-exp(lKe)*input) - exp(-exp(lKa)*input))/(exp(lKa) - exp(lKe)). If all of the arguments lKe, lKa, and lCl are names of objects, as opposed to expressions or explicit numerical values, the gradient matrix with respect to these names is attached as an attribute named gradient.

Author(s)

Jose Pinheiro and Douglas Bates

See Also

nls, selfStart

Examples

library( lme )
data( Theoph )
Theoph.1 <- Theoph[ Theoph$Subject == 1, ]
SSfol( Theoph.1$Dose, Theoph.1$Time, -2.5, 0.5, -3 )  # response only
lKe <- -2.5
lKa <- 0.5
lCl <- -3
SSfol( Theoph.1$Dose, Theoph.1$Time, lKe, lKa, lCl ) # response and gradient


[Package Contents]