b.cpp

b.cpp

hpx::future<std::uint64_t> fibonacci(std::uint64_t n, std::string prefix)
{
    if (n < 2) return hpx::make_ready_future(n);
    if (n < threshold) return hpx::make_ready_future(fibonacci_serial(n));

	auto new_prefix = prefix + "->" + std::to_string(n);
	std::cout << "[Debug] " << new_prefix << std::endl;

    hpx::future<std::uint64_t> lhs_future = hpx::async(&fibonacci, n-1, new_prefix);
	for (int i = 0; i < 1000000000; ++i) int j = i*i;
	hpx::future<std::uint64_t> rhs_future = fibonacci(n - 2, new_prefix);

	if (n == 10)
		auto aaarhs_future = fibonacci(n - 3, "X" + new_prefix);

    return
        hpx::dataflow(
            hpx::util::unwrapped(
            [](std::uint64_t lhs, std::uint64_t rhs)
            {
                return lhs + rhs;
            })
          , std::move(lhs_future), std::move(rhs_future)
        );
}

fibonacci_serial(10) == 55,elapsed time:,10867,[s]
[Debug] ->10
[Debug] ->10->8
[Debug] ->10->8->6
[Debug] ->10->8->6->4
[Debug] ->10->8->6->4->2
[Debug] X->10->7
[Debug] X->10->7->5
[Debug] X->10->7->5->3
[Debug] ->10->9
[Debug] ->10->9->7
[Debug] ->10->9->7->5