R/sample_df.R

In dill/ltdesigntester: Test Performance of Line Transect Designs

#' Sample data using a detection function
#'
#' @param df \code{DSsim} \code{Detectability} object defining the detection function
#' @param distances vector of distances
#' @return logical vector of the same length as \code{distances} indicating which objects were detected
sample_df <- function(df, distances){

  if(df@key.function=="hn"){
    g <- function(x, sigma, b){
      exp(-x^2/(2*sigma^2))
    }
  }else if(df@key.function=="hr"){
    g <- function(x, sigma, b){
      1-exp(-(x/sigma)^(-b))
    }
  }else{
    stop("Detection function not \"hr\" or \"hn\"")
  }

  as.logical(rbinom(length(distances), 1,
                    g(distances, sigma=df@scale.param, b=df@shape.param)))
}