A Reliable Totient Range Function in Parallel

A reliable implementation of the totient range function in Erlang. This is a parallel and distributed implementation. A server process is spawned, which watches over its worker processes that it will spawn NWorker number of (specified by the user). Its worker: totientWorker process will compute a section of the totient range, all workers will be accumulated in the server during the final step.

This program simulates an environment where any of its important processes may be killed at anytime (a Chaos Monkey). As such, a reliable implementation will restart them, and proceed as normal.

Totient Function

In number theory, Euler's totient function counts the positive integers up to a given integer n that are relatively prime to n. It is written using the Greek letter phi as ϕ or φ, and may also be called Euler's phi function.

Expected Output

> totientrange:testRobust(4, 3).
Watching ClientWorker worker1
Watching ClientWorker worker2
Watching ClientWorker worker3
Watching ClientWorker worker4
Worker : Computing Range 1 3750
Worker : Computing Range 3751 7500
Worker : Computing Range 7501 11250
Worker : Computing Range 11251 15000
workerChaos killing worker4
workerChaos killing worker1
workerChaos killing worker4 [ true , true , true ]
Worker : Finished
Server : Received Sum 4275174
Worker : Finished
Server : Received Sum 12824238
Worker : Finished
Server : Received Sum 21371600
Worker : Finished
Server : Received Sum 29923304
Server : Sum of totients : 68394316
Server : Time taken in Secs , MicroSecs 13 302830

Manual

compile from the shell: >c(totientrange).

NWorkers number of workers
ATotient beginning integer for totient range
BTotient ending integer for totient range
run from the shell: `>server ! {range, ATotient, BTotient, NWorkers}.