Setting seed when using future

tidyverse
, ,
1

Hi, I have some basic question regarding seeds when using parallelization. Suppose I would like to create a new column named SUM based on the numeric columns from the iris dataset:

library(tidyverse)
library(future)
library(furrr)

sum_function <- function(a, b, c, d){
  return (a + b + c + d + rnorm(1))
}

plan("multisession", workers = 1)

set.seed(42, kind = "L'Ecuyer-CMRG")

new_iris <- iris %>% 
  mutate(SUM = pmap(.l = list(Sepal.Length, Sepal.Width, Petal.Length, Petal.Width),
                    .f = sum_function))

future_iris <- iris %>% 
  mutate(SUM = future_pmap(.l = list(Sepal.Length, Sepal.Width, Petal.Length, Petal.Width),
                    .f = sum_function, 
                    .options = furrr_options(seed = 42)))

Unfortunately, the dataframes differ in their value in the SUM column. How can I fix this?