std::atomic<size_t> counter = 0;

size_t N = 1 << num_layers;

size_t *D = new size_t [N];

#pragma omp parallel num_threads(num_threads)

{

#pragma omp single

{

for(size_t i = 1; i<N; ++i) {

size_t p = i / 2;

size_t l = i * 2;

size_t r = l + 1;

if(l < N && r < N) {

#pragma omp task firstprivate(i) depend(out:D[l], D[r]) depend(in:D[p])

{

//printf("%d\n", i);

counter.fetch_add(1, std::memory_order_relaxed);

}

}

else {

#pragma omp task firstprivate(i) depend(in:D[p])

{

//printf("%d\n", i);

counter.fetch_add(1, std::memory_order_relaxed);

}

}

}

}

}

assert((counter + 1) == N);

delete [] D;

size_t num_layers,

unsigned num_threads

) {

auto beg = std::chrono::high_resolution_clock::now();

binary_tree_omp(num_layers, num_threads);

auto end = std::chrono::high_resolution_clock::now();

return std::chrono::duration_cast<std::chrono::microseconds>(end - beg);