CODEWITHSUNDEEP
copenmprace-condition
Shmoopy
Shmoopy

Reputation: 5534

OpenMP race condition?

I've read that variables in OpenMP are shared by default. Does this mean that in the following code, which is supposed to sum all the numbers from 0 to N-1, there is a race condition?

int sum = 0,i;
#pragma omp parallel for
for (i = 0; i < N; i++)
    sum+=i;

Upvotes: 1

Views: 1062

Answers (1)

Vladimir F Героям слава
Vladimir F Героям слава

Reputation: 59998

Yes, there is a race condition. You should add reduction(+:sum) to the pragma. This will effectively make invisible private copies in each thread and then sum them after the loop.

Upvotes: 3

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