omp_set_num_threads(nthreads);

int i, j, k;

#pragma omp parallel shared(a, b, c, nthreads) private(i, j, k)

{

#pragma omp for schedule (static)

for (i=0; i<N; i++)

for (j=0; j<N; j++)

a[i][j]= i+j;

#pragma omp for schedule (static)

for (i=0; i<N; i++)

for (j=0; j<N; j++)

b[i][j]= i*j;

#pragma omp for schedule (static)

for (i=0; i<N; i++)

for (j=0; j<N; j++)

c[i][j]= 0;

#pragma omp for schedule (static)

for (i=0; i<N; i++) {

for(j=0; j<N; j++) {

for (k=0; k<N; k++) {

c[i][j] += a[i][k] * b[k][j];

}

}

}

}

//std::cout << reduce_sum() << std::endl;

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

matrix_multiplication_omp(num_threads);

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

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