问题描述
我有一个简单的示例，尝试根据此carma使用pybind11和example来往犰狳矩阵和numpy数组之间来回。没有printarma（）函数，代码可以正常工作，即仅使用pybind11包装即可编译代码，我可以在python中运行它。这里的问题似乎与焦油有关。这是代码：
#include <ostream>
#include <iostream>
#include <armadillo>
#include <carma/carma.h>
#include <pybind11/pybind11.h>
#include <pybind11/numpy.h>
namespace py = pybind11;
using namespace std;
class Base
{
public:
virtual void test() = 0;
virtual void printarma() = 0;
};
class Derived: public Base
{
public:
void printarma(py::array_t<double> & arr) {arma::Mat<double> mat = carma::arr_to_mat<double>(arr);
std::cout << mat<< std::endl;}
void test() {cout << "Test";}
};
PYBIND11_MODULE(example,m) {
py::class_<Base>(m,"Base");
py::class_<Derived,Base>(m,"Derived")
.def(py::init<>())
.def("test",&Derived::test);
m.def("printarma",&Derived::printarma,py::arg("arr"));
}
我运行命令：
c++ -O3 -Wall -shared -std=c++14 -fPIC -larmadillo `python3 -m pybind11 --includes` abstrakt_test.cpp -o example`python3-config --extension-suffix`
错误是：
In file included from /home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:47,from /home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/numpy.h:12,from /usr/local/include/carma/carma/converters.h:24,from /usr/local/include/carma/carma/arraystore.h:1,from /usr/local/include/carma/carma.h:1,from abstrakt_test.cpp:18:
/home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/detail/init.h: In instantiation of ‘Class* pybind11::detail::initimpl::construct_or_initialize(Args&& ...) [with Class = Derived; Args = {}; typename std::enable_if<(! std::is_constructible<_Tp,_Args>::value),int>::type <anonymous> = 0]’:
/home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/detail/init.h:174:66: required from ‘static void pybind11::detail::initimpl::constructor<Args>::execute(Class&,const Extra& ...) [with Class = pybind11::class_<Derived,Base>; Extra = {}; typename std::enable_if<(! Class::has_alias),int>::type <anonymous> = 0; Args = {}]’
/home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:1148:9: required from ‘pybind11::class_<type_,options>& pybind11::class_<type_,options>::def(const pybind11::detail::initimpl::constructor<Args ...>&,const Extra& ...) [with Args = {}; Extra = {}; type_ = Derived; options = {Base}]’
abstrakt_test.cpp:45:26: required from here
/home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/detail/init.h:63:64: error: invalid new-expression of abstract class type ‘Derived’
inline Class *construct_or_initialize(Args &&...args) { return new Class{std::forward<Args>(args)...}; }
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
abstrakt_test.cpp:31:7: note: because the following virtual functions are pure within ‘Derived’:
class Derived: public Base
^~~~~~~
abstrakt_test.cpp:29:18: note: ‘virtual void Base::printarma()’
virtual void printarma() = 0;
^~~~~~~~~
In file included from /home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/numpy.h:12,from abstrakt_test.cpp:18:
/home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h: In instantiation of ‘void pybind11::cpp_function::initialize(Func&&,Return (*)(Args ...),const Extra& ...) [with Func = pybind11::cpp_function::cpp_function(Return (Class::*)(Arg ...),const Extra& ...) [with Return = void; Class = Derived; Arg = {pybind11::array_t<double,16>&}; Extra = {pybind11::name,pybind11::scope,pybind11::sibling,pybind11::arg}]::<lambda(Derived*,pybind11::array_t<double>&)>; Return = void; Args = {Derived*,pybind11::array_t<double,pybind11::arg}]’:
/home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:78:9: required from ‘pybind11::cpp_function::cpp_function(Return (Class::*)(Arg ...),pybind11::arg}]’
/home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:819:22: required from ‘pybind11::module& pybind11::module::def(const char*,Func&&,const Extra& ...) [with Func = void (Derived::*)(pybind11::array_t<double>&); Extra = {pybind11::arg}]’
abstrakt_test.cpp:47:55: required from here
/home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:133:50: error: static assertion Failed: The number of argument annotations does not match the number of function arguments
static_assert(expected_num_args<Extra...>(sizeof...(Args),cast_in::has_args,cast_in::has_kwargs),~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/attr.h:13,from /home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:44,from abstrakt_test.cpp:18:
/home/mikanim/anaconda3/envs/pybind/lib/python3.7/site-packages/pybind11/include/pybind11/cast.h:1958:57: error: ‘std::enable_if_t<std::is_void<_Res>::value,pybind11::detail::void_type> pybind11::detail::argument_loader<Args>::call(Func&&) && [with Return = void; Guard = pybind11::detail::void_type; Func = pybind11::cpp_function::cpp_function(Return (Class::*)(Arg ...),pybind11::array_t<double>&)>&; Args = {Derived*,16>&}; std::enable_if_t<std::is_void<_Res>::value,pybind11::detail::void_type> = pybind11::detail::void_type]’,declared using local type ‘pybind11::cpp_function::cpp_function(Return (Class::*)(Arg ...),pybind11::array_t<double>&)>’,is used but never defined [-fpermissive]
enable_if_t<std::is_void<Return>::value,void_type> call(Func &&f) && {
谢谢！
编辑：
不含逗号的代码：
c++ -O3 -Wall -shared -std=c++11 -fPIC `python3 -m pybind11 --includes` abstrakt_test.cpp -o example`python3-config --extension-suffix`
#include <ostream>
#include <iostream>
#include <pybind11/pybind11.h>
namespace py = pybind11;
using namespace std;
class Base
{
public:
virtual void test() = 0;
};
class Derived: public Base
{
public:
void test() {cout << "Test";}
};
PYBIND11_MODULE(example,&Derived::test);
}
解决方法
最后有两件事：基类中的虚函数需要向其添加py::array_t<double> & arr，而结尾处的分号.def需要与{{1 }}在m之前。这段代码可以在python中编译并工作：
.def