Facteurs_premiers.groovy

def primes(long upto) {
    def primes=[];
    // We only search primes below sqrt, as a result of algrebraic well knwon results
    long max = Math.max(Math.sqrt(upto), 1L);
    for(tested in 2..max) {
        long maxTested = Math.sqrt(tested);
        boolean isPrime = true;
        for(i in primes) {
            if(isPrime) {
                if(i<=maxTested) {
                    isPrime = tested%i!=0;
                } else {
                    break;
                }
            } else
                break;
        }
        if(isPrime) {
            if(primes.size()%1000==0)
                println "found new prime $tested (the "+primes.size()+"th)";
            primes << tested;
            
        } else {
            if(tested%10000==0) {
                println "reached $tested";
            }
        }
    }
    return primes;
}

long start = System.currentTimeMillis();
NUMBER = 131900005;
def p = primes(NUMBER);
// println "found primes "+p.join(", ");
primeDividors = p.findAll {n -> NUMBER%n==0};
println primeDividors.join(", ");
long end = System.currentTimeMillis();
println "duration "+((end-start)/1000.0)+" s";