Self-starter for the Cedergreen-Ritz-Streibig Dose-Response Model

A self-starting function for the Cedergreen-Ritz-Streibig model, used to find initial parameter estimates for non-linear regression (e.g., with nls or drc).

Usage

cedergreen.ssf(
  method = c("loglinear", "anke", "method3", "normolle"),
  fixed,
  alpha,
  useFixed = FALSE
)

Arguments

method

A character string specifying the method for estimating initial 'b' and 'e' parameters. Using descriptive names is preferred.

fixed

A numeric vector of fixed parameter values, with NA for parameters that need to be estimated. The required order is c(b, c, d, e, f).

alpha

A numeric value for the alpha parameter, which is treated as a known constant during the estimation of the other initial parameters.

useFixed

A logical value. If TRUE, the function will use the non-NA values provided in the fixed argument as fixed parameters and only estimate the others.

Value

A numeric vector of initial parameter estimates for the model parameters that were not specified as fixed.

Details

This function is a closure that returns another function. The returned function takes a data frame and calculates initial values for the model parameters (b, c, d, e, f). This self-starter relies on several helper functions (e.g., findcd, findbe1, findbe2, findbe3) which must be available in the calling environment.