R/node_negative_binomial.r

In simDAG: Simulate Data from a DAG and Associated Node Information

## generate data from a negative binomial regression
#' @export
node_negative_binomial <- function(data, parents, formula=NULL, betas,
                                   intercept, theta, link="log") {

  if (!data.table::is.data.table(data)) {
    data.table::setDT(data)
  }

  if (!is.null(formula)) {
    data <- stats::model.matrix(object=formula, data=data)
    data <- as.data.frame(data[, -1])
  } else {
    data <- as.data.frame(data[, parents, with=FALSE])
  }

  eta <- intercept + rowSums(mapply("*", data, betas))

  if (link=="log") {
    eta <- exp(eta)
  } else if (link=="sqrt") {
    eta <- eta^2
  }

  out <- stats::rnbinom(n=length(eta), mu=eta, size=theta)

  return(out)
}