Your code is nearly correct but has a few mistakes:
You don't need to be making the size_tag
since you are serializing the number of rows and columns explicitly. Generally cereal uses size_tag
for resizable containers like vectors or lists. Even though the matrix can resize, it makes more sense just to serialize the rows and columns explicitly.
- Your load function should accept its parameter by non-const reference
- You shouldn't use operator= with the
std::ofstream
objects - It's better practice to let scoping and RAII handle closing/tearing down of the
std::ofstream
as well as cereal archives (the binary archive will flush its contents immediately, but in general cereal archives are only guaranteed to flush their contents on destruction)
Here's a version that compiles and produces correct output under g++ and clang++:
#include <cereal/cereal.hpp>
#include <cereal/archives/binary.hpp>
#include <Eigen/Dense>
#include <fstream>
namespace cereal
{
template <class Archive, class _Scalar, int _Rows, int _Cols, int _Options, int _MaxRows, int _MaxCols> inline
typename std::enable_if<traits::is_output_serializable<BinaryData<_Scalar>, Archive>::value, void>::type
save(Archive & ar, Eigen::Matrix<_Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols> const & m)
{
int32_t rows = m.rows();
int32_t cols = m.cols();
ar(rows);
ar(cols);
ar(binary_data(m.data(), rows * cols * sizeof(_Scalar)));
}
template <class Archive, class _Scalar, int _Rows, int _Cols, int _Options, int _MaxRows, int _MaxCols> inline
typename std::enable_if<traits::is_input_serializable<BinaryData<_Scalar>, Archive>::value, void>::type
load(Archive & ar, Eigen::Matrix<_Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols> & m)
{
int32_t rows;
int32_t cols;
ar(rows);
ar(cols);
m.resize(rows, cols);
ar(binary_data(m.data(), static_cast<std::size_t>(rows * cols * sizeof(_Scalar))));
}
}
int main() {
Eigen::MatrixXd test = Eigen::MatrixXd::Random(10, 3);
{
std::ofstream out("eigen.cereal", std::ios::binary);
cereal::BinaryOutputArchive archive_o(out);
archive_o(test);
}
std::cout << "test:" << std::endl << test << std::endl;
Eigen::MatrixXd test_loaded;
{
std::ifstream in("eigen.cereal", std::ios::binary);
cereal::BinaryInputArchive archive_i(in);
archive_i(test_loaded);
}
std::cout << "test loaded:" << std::endl << test_loaded << std::endl;
}