% cat main.go
package main

import "flag"
import "fmt"
import "math"
import "rand"
import "time"

var numprocs *int = flag.Int("procs", 4, "number of processors")
var iterations *int = flag.Int("iter", int(1e6), "number of iterations per proc")

func pi(max_iterations int, r chan float64) {
    successes := 0

    var x float64
    var y float64

    for i := 0; i <= max_iterations; i++ {
        x = rand.Float64()
        y = rand.Float64()

        if math.Sqrt(x*x + y*y) <= 1.0 {
            successes++
        }
    }

    fmt.Println(successes, max_iterations)

    fraction := float64(successes) / float64(max_iterations)
        r <- fraction * 4
}

func main() {
        flag.Parse()
        rand.Seed(time.Nanoseconds())
        fmt.Println(*numprocs)

        pcount := *numprocs
        iteration_count := *iterations

        r := make(chan float64, pcount)

        for i := 0; i < pcount; i++ {
                go pi(iteration_count, r)
        }

        var total float64 = 0.0
        for i := 0; i < pcount; i++ {
                result := <-r
                total += result
        }

        fmt.Println(total / float64(pcount))
}