Primality

A distributed finder of prime written in Haskell. Because Haskell is cool. Distributed-ness to come later.

Build Instructions

Before you can build this application you will need a few things on your local machine. This program has only been tested on Linux-based systems, and although there is no reason to believe it won't work on Windows or OS/X, we make no promises.

General Requirements

1. GHC (The Glasgow Haskell Compiler)
   • Note that if you are using the Ubuntu repositories the version of GHC you install may be out of date.
2. Cabal gasp
3. The monad-par package (Installed from Cabal)

Extremely detailed requirements

In case the above is daunting, and assuming you are on Ubuntu (or an Ubuntu-based distribution) you may do the following:

sudo apt-get install haskell-package
cabal install monad-par

Actual build instructions

To build this program, run:

ghc main.hs primeTest.hs -rtsopts -threaded -O2

Using this program

At the moment, this application accepts two arguments - a lower bound and an upper bound. A few additional flags must be added to encourage it to run multiple threads.

./main <lowerBound> <upperBound> +RTS -N<threads>

lowerBound is, of course, the lower bound of the range to search. upperBound is, surprisingly, the upper bound of the range to search. threads specifies the number of threads to divide the work between. Leaving it blank will automatically determine the number of threads your system supports (either the number of cores, or the number of cores * 2 if you have hyperthreading) and use that many threads.

Timing program performance

We have here a very simple application that finds all the primes in a given range. Naturally the favorite use for such a program is comparing how long a given range takes on various CPUs. The example below finds the first 1 million prime numbers and dumps them into /dev/null, then it prints out how long that totally productive task took. Way to put that computer to good use, guys.

time ./main 1 15485864 +RTS -N > /dev/null

TODO:

• Make things look pretty
• add command line options