Problems compiling Boost::Python

Question

I want to use c++ numerical recipes on my python script but I am having some issues compiling some stuff in the Boost Python Libraries. Specificly I want to expose the amoeba function to python. I use Make rather than BJam. This is what I get when I try to compile:

costantinoagnesi@costantino-HP-Pavilion-dv5-Notebook-PC:~/Desktop/Boost Python Test$  make
g++ -I/usr/include/python2.7 -I/usr/include -fPIC -c amoeba_py.C
In file included from /usr/local/include/boost/python/object/make_instance.hpp:10:0,
               from /usr/local/include/boost/python/object/make_ptr_instance.hpp:8,
               from /usr/local/include/boost/python/to_python_indirect.hpp:11,
               from /usr/local/include/boost/python/converter/arg_to_python.hpp:10,
               from /usr/local/include/boost/python/call.hpp:15,
               from /usr/local/include/boost/python/object_core.hpp:14,
               from /usr/local/include/boost/python/args.hpp:25,
               from /usr/local/include/boost/python.hpp:11,
               from amoeba_py.C:73:
/usr/local/include/boost/python/converter/registered.hpp: In function ‘const boost::python::converter::registration&
boost::python::converter::detail::registry_lookup2(T& (*)()) [with T = double(const NRVec<double>&)]’:
/usr/local/include/boost/python/converter/registered.hpp:94:40:   instantiated from ‘const >boost::python::converter::registration& boost::python::converter::detail::registry_lookup1(boost::type<T>) [with T = double (&)(const NRVec<double>&)]’
/usr/local/include/boost/python/converter/registered.hpp:105:23:   instantiated from const boost::python::converter::registration& boost::python::converter::detail::registered_base<double (&)(const NRVec<double>&)>::converters’
/usr/local/include/boost/python/converter/arg_from_python.hpp:269:99:   instantiated from  ‘boost::python::converter::pointer_arg_from_python<T>::pointer_arg_from_python(PyObject*) [with T = double (*)(const NRVec<double>&), PyObject = _object]’
/usr/local/include/boost/python/arg_from_python.hpp:70:18:   instantiated from ‘boost::python::arg_from_python<T>::arg_from_python(PyObject*) [with T = double (*)(const NRVec<double>&), PyObject = _object]’
/usr/local/include/boost/preprocessor/iteration/detail/local.hpp:43:1:   instantiated from >‘PyObject* boost::python::detail::caller_arity<5u>::impl<F, Policies, Sig>::operator( (PyObject*, PyObject*) [with F = void (*)(NRMat<double>&, NRVec<double>&, double, double (*)(const NRVec<double>&), int&), Policies = boost::python::default_call_policies, Sig = boost::mpl::vector6<void, NRMat<double>&, NRVec<double>&, double, double (*)(const NRVec<double>&), int&>, PyObject = _object]’
/usr/local/include/boost/python/object/py_function.hpp:38:33:   instantiated from ‘PyObject* boost::python::objects::caller_py_function_impl<Caller>::operator()(PyObject*, PyObject*) [with Caller = boost::python::detail::caller<void (*)(NRMat<double>&, NRVec<double>&, double, double (*)(const NRVec<double>&), int&), boost::python::default_call_policies, boost::mpl::vector6<void, NRMat<double>&, NRVec<double>&, double, double (*)(const NRVec<double>&), int&> >, PyObject = _object]’ amoeba_py.C:79:1:   instantiated from here
/usr/local/include/boost/python/converter/registered.hpp:86:7: error: no matching function >for call to ‘register_shared_ptr1(double (*)(const NRVec<double>&))’
/usr/local/include/boost/python/converter/registered.hpp:86:7: note: candidate is:
/usr/local/include/boost/python/converter/registered.hpp:77:3: note: template<class T> void boost::python::converter::detail::register_shared_ptr1(const volatile T*)
make: *** [amoeba_py.o] Error 1

Can someone help me decipher what this error means and perhaps give me some helpful tip to finish my project. It's worth noting that the classic Boost Python example compiles just fine. Thank you!

Here's the offending text: (lines 73-79)

#include <boost/python.hpp>
using namespace boost::python;

BOOST_PYTHON_MODULE(amoeba)
{
     def("amoeba", NR::amoeba);
}

Answer 1

I suspect you're having a similar problem to the guy who asked this question. Are you passing a function pointer as an argument in your C++ code? If so, you can't do that in Python -- see the answer as to why.

Answer 2

You forgot reference operator. Thus the def is getting parameter type double (*)(const NRVec<double>&) instead of const volatile T* it expects.

Your code ought to look like this:

BOOST_PYTHON_MODULE(amoeba)
{
     def("amoeba", &NR::amoeba);
}