library("snow")
library("parallel")

cpu <- Sys.getenv("SLURM_CPUS_ON_NODE", 1) # Number of cores requested (use 1 core if running outside a job).
hosts <- rep("localhost",cpu)
cl <- makeCluster(hosts, type = "SOCK")
# Create random matrices.
n <- 5000
A <- matrix(rnorm(n^2),n)
B <- matrix(rnorm(n^2),n)

# Single core time of matrix multiplication of matrices
# A and B.
message("Single core matrix multiplication time: ")
system.time(A %*% B)

# Multiple core time of matrix multiplication of
# matrices A and B.
message("Parallel matrix multiplication time: ")
system.time(parMM(cl, A, B))

# Stop cores properly.
stopCluster(cl)