simple parallelization example

parallelization_test.r

# part of this code from Thiele's http://goo.gl/Ed1zrq

# call packages
library(parallel)
library(microbenchmark)


#create simple function
testfun1 <- function(x) {
    return(x*x)
}
my.v1 <- 1:10
print(my.v1)
my.v1.quad <- sapply(my.v1, testfun1)
print(my.v1.quad)


# detect the number of cores available
processors <- detectCores()
processors

# create cluster
cl <- makeCluster(processors)

# call parallel sapply
my.v1.quad.par <- parSapply(cl, my.v1, testfun1)
print(my.v1.quad.par)


#microbenchmark
compared <- microbenchmark(my.v1.quad, my.v1.quad.par, times=1000L)
print(compared)
boxplot(compared)

# stop cluster
stopCluster(cl)