Serialization of gtsam classes such as gtsam::NonlinearFactorGraph

[Timo Hinzmann]

Just a question: Is there a minimal working example for the serialization of e.g. gtsam::NonlinearFactorGraph?

With

  gtsam::NonlinearFactorGraph factors;
  gtsam::Symbol x1('x',1);
  gtsam::Pose2 prior(0.0, 0.0, 0.0);
  gtsam::noiseModel::Diagonal::shared_ptr priorNoise =
      gtsam::noiseModel::Diagonal::Sigmas(gtsam::Vector3(0.3, 0.3, 0.1));
  factors.add(gtsam::PriorFactor<gtsam::Pose2>(x1, prior, priorNoise));
  gtsam::serializeToFile(factors, "factor");

I get

terminate called after throwing an instance of 'boost::archive::archive_exception'
  what():  unregistered class - derived class not registered or exported

Same with gtsam::Values.

What am I missing? Thanks a lot.

[Frank Dellaert]

@jdong37 has experience with this.

[Jing Dong]

Hi @hitimo , that's a pitfall when using boost serialization for derived class. You need to call BOOST_CLASS_EXPORT_GUID to regester the derived class before trying to serialize it. See http://www.boost.org/doc/libs/1_32_0/libs/serialization/doc/special.html for explanation and gtsam/navigation/tests/testImuFactorSerialization.cpp as an example.

[Frank Dellaert]

Question answered

[Timo Hinzmann]

@jdong37 Thanks for the help.

[Tal Regev]

I add

BOOST_CLASS_EXPORT_GUID(gtsam::NonlinearFactorGraph, "NonlinearFactorGraph")

also try:

BOOST_CLASS_EXPORT(gtsam::NonlinearFactorGraph)
BOOST_CLASS_EXPORT_IMPLEMENT(gtsam::NonlinearFactorGraph)

and it say the same error:

terminate called after throwing an instance of 'boost::archive::archive_exception'
  what():  unregistered class - derived class not registered or exported

can you resolve it? @dellaert @jdong37
I am using gtsam 4.0.0 (from devel branch).

[Jing Dong]

Hi @talregev you need export the factor classes you use, not the factor graph class. For example, if you use Prior factor for Vector3 in the graph, try

typedef PriorFactor<Vector3>                    PriorFactorVector3;
BOOST_CLASS_EXPORT_GUID(PriorFactorVector3, "gtsam::PriorFactorVector3");

[Tal Regev]

it doesn't work. I will copy my program:

#include <gtsam/slam/PoseTranslationPrior.h>
#include <gtsam/base/serialization.h>
#include <gtsam/base/serializationTestHelpers.h>
#include <gtsam/geometry/Pose3.h>
#include <gtsam/geometry/Pose2.h>
#include <gtsam/slam/BetweenFactor.h>
#include <gtsam/slam/PriorFactor.h>
#include <gtsam/inference/Symbol.h>
#include <gtsam/nonlinear/NonlinearFactorGraph.h>


typedef gtsam::PriorFactor<gtsam::Pose2>    PriorFactorPose2;
typedef gtsam::BetweenFactor<gtsam::Pose2>  BetweenFactorPose2;


BOOST_CLASS_EXPORT_GUID(PriorFactorPose2,"gtsam::PriorFactorPose2")
BOOST_CLASS_EXPORT_GUID(BetweenFactorPose2, "gtsam::BetweenFactorPose2")

int main(int argc, char** argv) {

    gtsam::Key i1 = gtsam::symbol('x',1);
    gtsam::Key i2 = gtsam::symbol('x',2);
    gtsam::Key i3 = gtsam::symbol('x',3);
    gtsam::Key j1 = gtsam::symbol('l',1);
    gtsam::Key j2 = gtsam::symbol('l',2);

    gtsam::NonlinearFactorGraph graph;
    gtsam::Pose2 priorMean = gtsam::Pose2(0.0, 0.0, 0.0);
    gtsam::Vector sigma_p(3);
    sigma_p << 0.3, 0.3, 0.1;
    gtsam::SharedNoiseModel priorNoise = gtsam::noiseModel::Diagonal::Sigmas(sigma_p);
    PriorFactorPose2 prior = PriorFactorPose2(i1, priorMean, priorNoise);
    graph.add(prior);

    gtsam::Pose2 odometry = gtsam::Pose2(2.0, 0.0, 0.0);
    gtsam::Vector sigma(3);
    sigma << 0.2, 0.2, 0.2;
    gtsam::SharedNoiseModel odometryNoise = gtsam::noiseModel::Diagonal::Sigmas(sigma);

    graph.add(BetweenFactorPose2(i1, i2, odometry, odometryNoise));
    graph.add(BetweenFactorPose2(i2, i3, odometry, odometryNoise));

    std::string serialized;
    serialized = gtsam::serialize(graph);
    std::cout << serialized;
    return 0;
}

[Tal Regev]

do you have a tests cpp or example that i can compile?

[Tal Regev]

i copy all definition from testSerializationSLAM.cpp then it work :\

[Life Zero]

I got the same error there. I try BOOST_CLASS_EXPORT_GUID and all definition from testSerializationSLAM.cpp but error still in gtsam::Values and gtsam::NonlinearFactorGraph. Anyone can help me ?

[Frank Dellaert]

You need to make sure all factors you want to export are registered. Can’t be of much help beyond this. PS we migrated to GitHub years ago, might want to re-open an issue there if it still does not work, although this might be more for the google user group.

[José Luis Blanco-Claraco]

Start from this source code:

https://github.com/borglab/gtsam/blob/develop/tests/testSerializationSLAM.cpp

Make sure of adding boost macros for every single class and template instance you use in your program! It’s really hard to debug since boost error messages doesn’t help, but in the end it works

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