A.4 Using the nowait Clause
If there are multiple independent loops within a parallel region, you can use the nowait clause (Section 2.4.1 on page 11) to avoid the implied barrier at the end of the for directive, as follows:
#pragma omp parallel
{
#pragma omp for nowait
for (i=1; i<n; i++)
b[i] = (a[i] + a[i-1]) / 2.0;
#pragma omp for nowait
for (i=0; i<m; i++)
y[i] = sqrt(z[i]);
}