Lucas-Lehmer test: Difference between revisions

=={{header|D}}==

{{trans|Python}}

<lang d>import std.stdio, std.algorithm, std.range, std.math, std.conv ;

import std.bigint, core.thread ;

bool isPrime(int p) {

if(p < 2 || p % 2 == 0) return p == 2 ;

foreach( i ; iota(3, max(to!uint(sqrt(p)),3) + 1,2))

if(p % i == 0)

return false ;

return true ;

}

bool isMersennePrime(int p) {

if(!isPrime(p)) return false ;

if(p == 2) return true ;

auto mp = (BigInt(1) << p) - 1 ;

auto s = BigInt(4) ;

foreach(_ ; iota(3, p + 1))

s = (s*s - 2) % mp ;

return s == 0 ;

}

void main() {

int[] result ;

auto tgroup = new ThreadGroup ;

foreach(p ; iota(2,1000))

tgroup.add(new class (p) Thread {

int num ;

this(int n) { num = n ; super(&run) ; }

private void run() {

if(isMersennePrime(num))

result ~= num ;

}

}) ;

foreach(t ; tgroup)

t.start() ;

tgroup.joinAll() ;

writeln(reduce!`a~" "~b`(map!`"M"~to!string(a)`(result.sort))) ;

}</lang>

Output:

<pre>M2 M5 M7 M13 M17 M19 M31 M61 M89 M107 M127 M521 M607</pre>