demo for ZeroMQ on R Pi caluculation

master.R

library('rzmq')

context = init.context()
sock1 = init.socket(context,"ZMQ_PUSH")
bind.socket(sock1,"ipc:///test1")
sock2 = init.socket(context,"ZMQ_PULL")
bind.socket(sock2,"ipc:///test2")

nw <- 10000

n <- 100000000

pai_func <- function(n) {
  x <- runif(n,0,1)
  y <- runif(n,0,1)
  return(4*length(which(x*x+y*y<1))/n)
}

n_unit <- n / nw
for (i in 1:nw) {
  send.socket(sock1,list(pai_func,n_unit))
}

sum <- 0
for (i in 1:nw) {
  res <- receive.socket(sock2)
  sum <- sum+res
}
pai <- sum / nw

print(paste("pi =",pai))

slave.R

library('rzmq')

context = init.context()
sock1 = init.socket(context,"ZMQ_PULL")
connect.socket(sock1,"ipc:///test1")
sock2 = init.socket(context,"ZMQ_PUSH")
connect.socket(sock2,"ipc:///test2")

while (1) {
      u <- receive.socket(sock1)
      func <- u[[1]]
      n <- u[[2]]
      res <- func(n)
      send.socket(sock2,res)
}

standalone.R

n <- 100000000

pai <- function(n) {
  x <- runif(n,0,1)
  y <- runif(n,0,1)
  return(4*length(which(x*x+y*y<1))/n)
}

print(paste("pi =",pai(n)))

test.sh

Rscript slave.R &
Rscript slave.R &
Rscript slave.R &
Rscript slave.R &
Rscript slave.R &
Rscript slave.R &
Rscript slave.R &
Rscript slave.R &
Rscript slave.R &
Rscript slave.R &

echo 'stand alone test'
time Rscript standalone.R

echo 'many process test'
time Rscript master.R