fibonacci_device.cc

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// SPDX-License-Identifier: BSD-3-Clause
#include <ttg.h>
 
#if defined(TTG_HAVE_CUDA)
#define ES ttg::ExecutionSpace::CUDA
#include "cuda_runtime.h"
#include "fibonacci_cuda_kernel.h"
#else
#error " CUDA  is required to build this test!"
#endif
 
#include "ttg/serialization.h"
 
const int64_t F_n_max = 1000;
struct Fn : public ttg::TTValue<Fn> {
  std::unique_ptr<int64_t[]> F;  // F[0] = F_n, F[1] = F_{n-1}
  ttg::Buffer<int64_t> b;
 
  Fn() : F(std::make_unique<int64_t[]>(2)), b(F.get(), 2) { F[0] = 1; F[1] = 0; }
 
  Fn(const Fn&) = delete;
  Fn(Fn&& other) = default;
  Fn& operator=(const Fn& other) = delete;
  Fn& operator=(Fn&& other) = default;
 
  template <typename Archive>
  void serialize(Archive& ar) {
    ttg::ttg_abort();
  }
  template <typename Archive>
  void serialize(Archive& ar, const unsigned int) {
    ttg::ttg_abort();
  }
};
 
auto make_ttg_fib_lt(const int64_t F_n_max = 1000) {
  ttg::Edge<int64_t, Fn> f2f;
  ttg::Edge<void, Fn> f2p;
 
  auto fib = ttg::make_tt<ES>(
      [=](int64_t n, Fn&& f_n) -> ttg::device::Task {
        assert(n > 0);
        ttg::trace("in fib: n=", n, " F_n=", f_n.F[0]);
 
        co_await ttg::device::select(f_n.b);
 
        next_value(f_n.b.current_device_ptr());
 
        // wait for the task to complete and the values to be brought back to the host
        co_await ttg::device::wait(f_n.b);
 
        if (f_n.F[0] < F_n_max) {
          co_await ttg::device::forward(ttg::device::send<0>(n + 1, std::move(f_n)));
        } else {
          co_await ttg::device::forward(ttg::device::sendv<1>(std::move(f_n)));
        }
      },
      ttg::edges(f2f), ttg::edges(f2f, f2p), "fib");
  auto print = ttg::make_tt(
      [=](Fn&& f_n) {
        std::cout << "The largest Fibonacci number smaller than " << F_n_max << " is " << f_n.F[1] << std::endl;
      },
      ttg::edges(f2p), ttg::edges(), "print");
 
  auto ins = std::make_tuple(fib->template in<0>());
  std::vector<std::unique_ptr<::ttg::TTBase>> ops;
  ops.emplace_back(std::move(fib));
  ops.emplace_back(std::move(print));
  return make_ttg(std::move(ops), ins, std::make_tuple(), "Fib_n < N");
}
 
int main(int argc, char* argv[]) {
  ttg::initialize(argc, argv, -1);
  ttg::trace_on();
  int64_t N = 1000;
  if (argc > 1) N = std::atol(argv[1]);
 
  // make TTG
  auto fib = make_ttg_fib_lt(N);  // computes largest F_n < N
  // program complete, declare it executable
  ttg::make_graph_executable(fib.get());
  // start execution
  ttg::execute(ttg::ttg_default_execution_context());
  // start the computation by sending the first message
  if (ttg::default_execution_context().rank() == 0)
    fib->template in<0>()->send(1, Fn{});;
  // wait for the computation to finish
  ttg::fence(ttg::ttg_default_execution_context());
 
  ttg::finalize();
  return 0;
}