R/rbimod.r

In simglm: Simulate Models Based on the Generalized Linear Model

#' Simulating mixture normal distributions
#' 
#' Input simulation metrics returns mixture normal random variable.
#' 
#' Function to simulate mixture normal distributions.  The function computes
#' adds the specified number of normal distributions into a single vector.
#' 
#' Use of the function \code{\link{desireVar}} can be used to generate a mixture 
#' normal distribution with a specific global variance.
#' 
#' @param n Number of random draws.  Optionally can be a vector with number 
#'  in each simulated normal distribution.
#' @param mean Vector of mean values for each normal distribution.
#' Must be the same length as num_dist.
#' @param var Vector of variance values for each normal distribution.
#' Must be the same length as num_dist.
#' @param num_dist Number of normal distributions to use when simulating mixture
#'  normal distribution.
#' @export 
rbimod <- function(n, mean, var, num_dist){
  if(length(mean) != num_dist) stop("length of mean must equal num_dist")
  if(length(var) != num_dist) stop("length of var must equal num_dist")
  
  if(length(n) > 1) {
    unlist(lapply(1:num_dist, function(xx) rnorm(n[xx], mean = mean[xx], 
                                                 sd = var[xx])))
  } else {
    unlist(lapply(1:num_dist, function(xx) rnorm(n/num_dist, mean = mean[xx], 
                                                 sd = var[xx])))
  }

}