R/td2pLL.R

In jcduda/td2pLL: Fitting a time-dose two-parameter log-logistic model to time-dose-response data

# function: td2pLL
#' @export
#' @title Calculate response value for given td2pLL model
#' @description `td2pLL` returns the response value of a fully specified
#'  time-dose two-parameter log-logistic model at a certain time (t) and dose (d)
#'  value:
#'  \deqn{f(d,t)=100-100\frac{d^h}{EC_{50}(t)^h + d^h}}
#'  with
#'  \deqn{EC_{50}(t) = \Delta \cdot t^{-\gamma} + C_0}
#' @param time (`numeric(1)`)\cr
#'  Time value at which the response shall be calculated. Must be greater than 0.
#' @param dose numeric for the dose (or concentration) value where the response
#'  shall be calculated
#' @param h (`numeric(1)`)\cr
#'  The `h` parameter of the model.
#' @param gamma (`numeric(1)`)\cr
#'  The `gamma` parameter of the model.
#' @param c0 (`numeric(1)`)
#'  The `c0` parameter of the model.
#' @param delta (`numeric(1)`)\cr
#'  The `delta` parameter of the model.
#' @return (`numeric(1)`)\cr
#'  The response value of the model _in percent_ at the given `time` and
#'  `dose` value.
#' @examples
#'  td2pLL(time = 4, dose = 0.1, h = 2, gamma = 2.5, c0 = 0.1, delta = 0.3)
td2pLL <- function(time, dose, h, gamma, c0, delta) {
  ED50 <- delta * time^(-gamma) + c0
  resp <- 100 - 100 * (dose^h) / (ED50^h + dose^h)
  return(resp = resp)
}