primes_tbb

//=======================================================================
//
// SAMPLE SOURCE CODE - SUBJECT TO THE TERMS OF END-USER LICENSE AGREEMENT FOR
// INTEL(R) PARALLEL ADVISOR 2011.
//
// Copyright 2009-2010 Intel Corporation
//
// THIS FILE IS PROVIDED "AS IS" WITH NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT
// NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE, NON-INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS.
//
// ========================================================================

#include "stdafx.h"
#include <stdio.h>
#include <tbb/mutex.h>
#include <tbb/blocked_range.h>
#include <tbb/parallel_for.h>
#include <tbb/partitioner.h>

typedef tbb::blocked_range<int> int_blocked_range;

const int limit         = 3000000;
const int correctCount  = 216816;
int primes = (limit >= 2) ? 1 : 0;  // two is a prime, so count it
tbb::mutex primeMutex;

void Tick() {
    tbb::mutex::scoped_lock lockUntilScopeExit(primeMutex);
    primes++;
}

bool IsPrime(int p) {
    for (int i = 3; i*i <= p; i += 2) {
        if (p/i*i == p) return false;
    }
    return true;
}
class LoopBody {
public:
    LoopBody() {}
    void operator() (const int_blocked_range& range) const {
        const int upper = 3 + 2*range.end();  // expand range
        for (int p = 3 + 2*range.begin(); p < upper; p+=2) {
            if (IsPrime(p)) Tick();
        }
    }
 };

#include <tbb/task_scheduler_init.h>

int _tmain(int argc, _TCHAR* argv[])
{
    tbb::task_scheduler_init tsi;

    tbb::parallel_for(
        int_blocked_range(3-3, (limit-3)/2 + 1),   // make contiguous range 0..
        LoopBody(),
        tbb::auto_partitioner());

    printf("primes = %d\n", primes);
    return primes != correctCount;
}