// Matrix-vector multiplication, inner level parallelization.
#define N 1000

double a[N][N],v[N],v_out[N];

void mv()
{           
  int i,j;
  for (i = 0; i < N; i++)
  {         
    float sum = 0.0;
#pragma omp parallel for reduction(+:sum)
    for (j = 0; j < N; j++)
    { 
      sum += a[i][j]*v[j];
    }  
    v_out[i] = sum;
  }         
}

int main()
{
  mv();
  return 0;
}