I've tested out your code and it also did not work when I tried to compile it. However, based on the documentation for Boost Serialize, I am under the impression that it is intended to be used with the stream operator <<. The following code works fine for me:
namespace boost {
namespace serialization {
template <class Archive, typename Derived>
void serialize( Archive & ar, Eigen::EigenBase<Derived> & g, const unsigned int version){
ar & boost::serialization::make_array(g.derived().data(), g.size());
}
}
}
int main (int argc, char* argv[]){
std::ofstream out("my_archive");
boost::archive::text_oarchive oa (out);
Eigen::Matrix <double, 4, 4> a;
out << a;
return 0;
}
The file my_archive is created in the working folder with non-zero values (just the uninitialized garbage in memory, with the above over-simplified code).
EDIT:
I tried using the exact code above in my own application and found that I received the same error as you did. I honestly do not understand why that it, right now. The simplest fix that I found was to replace Eigen::EigenBase<Derived> with the actual Matrix type being used. The current code that I am using is:
namespace boost{
namespace serialization {
template <class Archive, typename Scalar>
void serialize ( Archive & ar, Eigen::Matrix<Scalar, -1, -1, 0, -1, -1> & g, const unsigned int version ){ /* ... */ }
}
}
The above code works for any scalar type (float, double, int) and for dynamic/runtime sized matrixes. For static sized, check into and update the template parameters accordingly.
EDIT #2 (April 09, 2014):
Despite the appearance of the above code working, when I tried to integrate it fully into my code and exercise it with appropriate unit testing, it stopped working. Unfortunately, the error messages that I was being given -- both from Visual Studio and clang -- were most unhelpful. Fortunately, gcc had buried within the horrible mess of error messages, a reference to CV-mismatch, which seems to have allowed me to fully address this.
The following code now appears to compile and run successfully. I've tried to make the formatting legible (without side-scrolling) -- hopefully the code below is clear:
namespace boost{
namespace serialization{
template< class Archive,
class S,
int Rows_,
int Cols_,
int Ops_,
int MaxRows_,
int MaxCols_>
inline void save(
Archive & ar,
const Eigen::Matrix<S, Rows_, Cols_, Ops_, MaxRows_, MaxCols_> & g,
const unsigned int version)
{
int rows = g.rows();
int cols = g.cols();
ar & rows;
ar & cols;
ar & boost::serialization::make_array(g.data(), rows * cols);
}
template< class Archive,
class S,
int Rows_,
int Cols_,
int Ops_,
int MaxRows_,
int MaxCols_>
inline void load(
Archive & ar,
Eigen::Matrix<S, Rows_, Cols_, Ops_, MaxRows_, MaxCols_> & g,
const unsigned int version)
{
int rows, cols;
ar & rows;
ar & cols;
g.resize(rows, cols);
ar & boost::serialization::make_array(g.data(), rows * cols);
}
template< class Archive,
class S,
int Rows_,
int Cols_,
int Ops_,
int MaxRows_,
int MaxCols_>
inline void serialize(
Archive & ar,
Eigen::Matrix<S, Rows_, Cols_, Ops_, MaxRows_, MaxCols_> & g,
const unsigned int version)
{
split_free(ar, g, version);
}
} // namespace serialization
} // namespace boost
A few critical points on the above code:
This code now has templated parameters for all of Eigen's Matrix parameters. This should allow it to work with all types of matrices and vectors, whether sized at compile-time or run-time. This is a major enhancement over the above code
It is essential that the serialization code be split into separate save and load functions. Otherwise, the deserialization code will not resize the matrix to hold the original data. I believe that Boost::Serialize does provide some additional functions that can be overloaded to perform operations on serialization or deserialization, but this approach was easier to implement.
The const qualifier on the save method is essential. This was the source of my troubles before an obscure g++ error keyed me in on this.
I cannot say that I have fully stress-tested this code yet. If you (or anyone else) finds any more problems with it, please do let me know and I'll try and follow up with anything else that I find.
Trust that that helps.
Shmuel
