Find a way to use different explicit template instantiation C++ library in the same program

[jorisv]

Explicit template instantiation C++ library use a context file that define the custom scalar to be used.

This custom scalar is a globally defined, and then, it's impossible to have the explicit template instantiation defined for two custom scalar type in the same C++ file.

By example the following code will be able to use explicit template instantiation for double but not for cppad:

#include "pinocchio/autodiff/cppad.hpp"
#include "pinocchio/multibody/model.hpp"
#include "pinocchio/multibody/data.hpp"
#include "pinocchio/multibody/sample-models.hpp"

typedef pinocchio::ModelTpl<CppAD::AD<double>> ADModel;
typedef pinocchio::DataTpl<CppAD::AD<double>> ADData;

int main()
{
  pinocchio::Model model;
  pinocchio::buildModels::manipulator(model);
  pinocchio::Data data(model);

  ADModel ad_model = model.cast<CppAD::AD<double>>();
  ADData ad_data(ad_model);
}

We should find another way to declare explicit template instantiation that allow to declare it to multiple scalar type.