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Three-Phase Dose-Response Model

Source: R/threephase.R
threephase.Rd

A ten-parameter dose-response model combining three log-logistic components, extending the two-phase model (twophase) for describing even more complex dose-response patterns.

Usage

threephase(
  fixed = c(NA, NA, NA, NA, NA, NA, NA, NA, NA, NA),
  names = c("b1", "c1", "d1", "e1", "b2", "d2", "e2", "b3", "d3", "e3"),
  fctName,
  fctText
)

Arguments

fixed

numeric vector specifying which parameters are fixed and at what value they are fixed. NAs are used for parameters that are not fixed.

names

a vector of character strings giving the names of the parameters (should not contain ":"). The default is reasonable.

fctName

optional character string used internally by convenience functions.

fctText

optional character string used internally by convenience functions.

Value

A list containing the nonlinear function, the self starter function, and the parameter names.

Details

The model function is the sum of a four-parameter log-logistic model and two three-parameter log-logistic models:

$$f(x) = \mathrm{LL.4}(x; b1, c1, d1, e1) + \mathrm{LL.3}(x; b2, d2, e2) + \mathrm{LL.3}(x; b3, d3, e3)$$

See also

twophase, llogistic

Author

Christian Ritz