如何序列化犰狳的载体 [英] How to serialize armadillo's vector

问题描述

如何序列化arma::Col?以下是MWE和错误输出.

How can I serialize arma::Col? Below are a MWE and the error output.

MWE:

#include <boost/mpi/environment.hpp>
#include <boost/mpi/communicator.hpp>
#include <iostream>
#include "armadillo"

namespace mpi = boost::mpi;

struct S
{   
    int i;
    arma::Col<double>::fixed<3> cvector;

    friend class boost::serialization::access;

    template<class Archive>
    void serialize(Archive& ar, const unsigned int version) 
    {
        ar& i;
        ar& cvector;
    }
};

int main()
{ 
    mpi::environment env;
    mpi::communicator world;

    S s;

    if (world.rank() == 0)
    {
        s.cvector[0] = 2;
        s.cvector[1] = 2;
        world.send(1, 0, s);
    }
    else
    {
        world.recv(0, 0, s);
        std::cout << s.cvector[0] << std::endl;
        std::cout << s.cvector[1] << std::endl;
    }

    return 0;
}

错误输出(跳过需要"内容)

error: ‘class arma::Col<double>::fixed<3ull>’ has no member named ‘serialize’; did you mean ‘set_size’? t.serialize(ar, file_version);

error: ‘class arma::Col<double>::fixed<3ull>’ has no member named ‘serialize’; did you mean ‘set_size’? t.serialize(ar, file_version);

此帖子似乎与我的问题有关，很遗憾，该问题没有得到答案.

This post seems to be related to my question and unfortunately it is unanswered.

推荐答案

问题的真正症结在于您想向各种Armadillo对象添加serialize()成员函数，但这似乎并不是可能...除了在Armadillo中巧妙地使用了预处理器之外，确实如此！

The real crux of the issue here is that you want to add a serialize() member function to the various Armadillo objects, but that doesn't appear to be possible... except that thanks to a clever use of the preprocessor in Armadillo, it is!

看看Mat_bones.hpp和Col_bones.hpp ...，您会在Mat和Col的类定义内看到类似的内容:

Take a look at Mat_bones.hpp and Col_bones.hpp... you'll see something like this, inside of the class definitions of Mat and Col:

public:

#ifdef ARMA_EXTRA_COL_PROTO
  #include ARMA_INCFILE_WRAP(ARMA_EXTRA_COL_PROTO)
#endif

当我发现它时，这让我感到非常高兴，因为现在我可以做一些定义为Mat_extra_bones.hpp的文件了:

It made me very happy when I found this, because now I can do something like define a file called Mat_extra_bones.hpp:

//! Add a serialization operator.
template<typename Archive>
void serialize(Archive& ar, const unsigned int version);

，然后Mat_extra_meat.hpp:

// Add a serialization operator.
template<typename eT>
template<typename Archive>
void Mat<eT>::serialize(Archive& ar, const unsigned int /* version */)
{
  using boost::serialization::make_nvp;
  using boost::serialization::make_array;

  const uword old_n_elem = n_elem;

  // This is accurate from Armadillo 3.6.0 onwards.
  // We can't use BOOST_SERIALIZATION_NVP() because of the access::rw() call.
  ar & make_nvp("n_rows", access::rw(n_rows));
  ar & make_nvp("n_cols", access::rw(n_cols));
  ar & make_nvp("n_elem", access::rw(n_elem));
  ar & make_nvp("vec_state", access::rw(vec_state));

  // mem_state will always be 0 on load, so we don't need to save it.
  if (Archive::is_loading::value)
  {
    // Don't free if local memory is being used.
    if (mem_state == 0 && mem != NULL && old_n_elem > arma_config::mat_prealloc)
    {
      memory::release(access::rw(mem));
    }

    access::rw(mem_state) = 0;

    // We also need to allocate the memory we're using.
    init_cold();
  }

  ar & make_array(access::rwp(mem), n_elem);
}

然后，在您的程序中，您所需要做的就是

Then, in your program, all you need to do is

#define ARMA_EXTRA_MAT_PROTO mat_extra_bones.hpp
#define ARMA_EXTRA_MAT_MEAT mat_extra_meat.hpp

和serialize()函数将是Mat类的成员.您可以轻松地将此解决方案改编为其他犰狳类型.

and the serialize() function will be a member of the Mat class. You can easily adapt this solution for other Armadillo types.

实际上，这正是mlpack库的内容( http://www.mlpack.org/)确实如此，因此，如果您有兴趣，可以仔细看看我在此处实现的确切解决方案:

In fact this is exactly what the mlpack library (http://www.mlpack.org/) does, so if you are interested you can take a closer look at the exact solution I implemented there:

https://github.com/mlpack/mlpack/tree/master/src/mlpack/core/arma_extend

这篇关于如何序列化犰狳的载体的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！