Parallelを使ってモンテカルロを並列計算

ParallelMontecarlo.php

<?php

const N = 100000000;

$para_count = 12;
$parallel = new ParallelFor(function(int $c){
    $x = mt_rand() / mt_getrandmax();
    $y = mt_rand() / mt_getrandmax();
    if(($x**2 + $y**2)**2 < 1) $c++;
    return $c;
}, N, $para_count);

$c = 0;
for($i=0;$i<$para_count;$i++){
    $c += $parallel->getFutures()[$i]->value();
}
$pi = 4*$c/N;
var_dump($pi);


class ParallelFor {

    public function __construct(Closure $func, int $count, int $max_parallel){
        $this->func = $func;
        if($count < $max_parallel){
            echo 'count < max_parallel', PHP_EOL;
            return;
        }
        $this->count = $count;
        $this->max_parallel = $max_parallel;

        $futures = [];
        for($i=0;$i<$max_parallel;$i++){
            $runtime = ParallelFactory::create();
            $futures[] = $runtime->run(function() use ($func, $i, $count, $max_parallel){
                $c = 0;
                for($j=($count/$max_parallel)*$i;$j<($count/$max_parallel)*($i+1);$j++){
                    $c = ($func)($c);
                }
                return $c;
            });
        }
        $this->futures = $futures;
    }

    public function getFunction(){
        return $this->func;
    }

    public function getFutures(){
        return $this->futures;
    }

    public function getMaxParallel(){
        return $this->max_parallel;
    }
}


class ParallelFactory {

    public static function create(){
        return new \parallel\Runtime;
    }

}

汎用性のある書き方を見つけたい