Comments on: A Simple TBB Program: TBB Prime http://www.kerrywong.com/2008/06/22/a-simple-tbb-program-tbb-prime/ Fri, 12 Mar 2010 01:25:24 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: kwong http://www.kerrywong.com/2008/06/22/a-simple-tbb-program-tbb-prime/comment-page-1/#comment-12098 kwong Sat, 12 Jul 2008 23:58:07 +0000 http://www.kerrywong.com/2008/06/22/a-simple-tbb-program-tbb-prime/#comment-12098 The default blocked_range does not divide odd-number-only range correctly. Thus the operator() loop needs to be changed to <code> for (size_t i = r.begin(); i < r.end(); i++) { test_prime(i); } </code> and the main loop in test_prime needs to be changed to <code> for (int i = 2; i <= sqrt((double) num); i+=1) { if (num % i == 0) { is_prime = false; break; } } </code> The default blocked_range does not divide odd-number-only range correctly. Thus the operator() loop needs to be changed to

for (size_t i = r.begin(); i < r.end(); i++)
{
test_prime(i);
}

and the main loop in test_prime needs to be changed to


for (int i = 2; i < = sqrt((double) num); i+=1)
{
if (num % i == 0)
{
is_prime = false;
break;
}
}

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