I am currently working on a project which deals with geometric problems. Since this project will be used commercially I cannot use libraries like CGAL.
I am currently using boost::geometry with inexact types but I encountered numeric issues.
I tried to simply use an exact point type from boost::multiprecision but it doesn't compile when I call boost::geometry functions.
I found this page which shows how to use a numeric_adaptor to use boost::geometry with exact number types. However, it seems outdated and I wasn't able to make it work.
Can boost::geometry be used with exact number types ? How ?
#include <vector>
#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point_xy.hpp>
#include <boost/geometry/geometries/segment.hpp>
#include <boost/geometry/algorithms/intersection.hpp>
#include <boost/multiprecision/gmp.hpp>
namespace bg = boost::geometry;
namespace bm = boost::multiprecision;
typedef bg::model::d2::point_xy<bm::mpq_rational> point;
typedef boost::geometry::model::segment<point> segment;
int main(void)
{
point a(0,0);
point b(1,0);
point c(1,1);
point d(0,1);
segment s1(a,c);
segment s2(b,d);
std::vector<point> ip;
bg::intersection(s1, s2, ip); // Doesn't compile
return 0;
}
clang++3.4.2 output:
In file included from boost_geom_intersect.cpp:3:
In file included from /usr/include/boost/geometry.hpp:17:
In file included from /usr/include/boost/geometry/geometry.hpp:36:
In file included from /usr/include/boost/geometry/core/radian_access.hpp:21:
In file included from /usr/include/boost/numeric/conversion/cast.hpp:33:
In file included from /usr/include/boost/numeric/conversion/converter.hpp:14:
/usr/include/boost/numeric/conversion/converter_policies.hpp:187:69: error: cannot convert 'const
boost::multiprecision::detail::expression<boost::multiprecision::detail::divides,
boost::multiprecision::detail::expression<boost::multiprecision::detail::multiply_immediates,
boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
void, void>, boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, void, void>' to 'result_type' (aka 'double') without a conversion
operator
static result_type low_level_convert ( argument_type s ) { return static_cast<result_type>(s) ; }
^~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/boost/numeric/conversion/detail/converter.hpp:524:32: note: in instantiation of member function
'boost::numeric::raw_converter<boost::numeric::conversion_traits<double, boost::multiprecision::detail::expression<boost::multiprecision::detail::divides,
boost::multiprecision::detail::expression<boost::multiprecision::detail::multiply_immediates,
boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
void, void>, boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, void, void> > >::low_level_convert' requested here
return RawConverterBase::low_level_convert(s);
^
/usr/include/boost/numeric/conversion/cast.hpp:53:27: note: in instantiation of member function
'boost::numeric::convdetail::non_rounding_converter<boost::numeric::conversion_traits<double,
boost::multiprecision::detail::expression<boost::multiprecision::detail::divides,
boost::multiprecision::detail::expression<boost::multiprecision::detail::multiply_immediates,
boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
void, void>, boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, void, void> >,
boost::numeric::convdetail::dummy_range_checker<boost::numeric::conversion_traits<double,
boost::multiprecision::detail::expression<boost::multiprecision::detail::divides,
boost::multiprecision::detail::expression<boost::multiprecision::detail::multiply_immediates,
boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
void, void>, boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, void, void> > >,
boost::numeric::raw_converter<boost::numeric::conversion_traits<double, boost::multiprecision::detail::expression<boost::multiprecision::detail::divides,
boost::multiprecision::detail::expression<boost::multiprecision::detail::multiply_immediates,
boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
void, void>, boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, void, void> > > >::convert' requested here
return converter::convert(arg);
^
/usr/include/boost/geometry/policies/robustness/segment_ratio.hpp:146:22: note: in instantiation of function template specialization 'boost::numeric_cast<double,
boost::multiprecision::detail::expression<boost::multiprecision::detail::divides,
boost::multiprecision::detail::expression<boost::multiprecision::detail::multiply_immediates,
boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
void, void>, boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, void, void> >' requested here
: boost::numeric_cast<double>
^
/usr/include/boost/geometry/policies/robustness/segment_ratio.hpp:129:9: note: in instantiation of member function
'boost::geometry::segment_ratio<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1> >::initialize' requested here
initialize();
^
/usr/include/boost/geometry/strategies/cartesian/cart_intersect.hpp:207:33: note: in instantiation of member function
'boost::geometry::segment_ratio<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1> >::assign' requested here
sinfo.robust_ra.assign(robust_da, robust_da0);
^
/usr/include/boost/geometry/algorithms/detail/overlay/intersection_insert.hpp:114:47: note: in instantiation of function template specialization
'boost::geometry::strategy::intersection::relate_cartesian_segments<boost::geometry::policies::relate::segments_intersection_points<boost::geometry::segment_intersection_points<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational,
1>, boost::geometry::cs::cartesian>, boost::geometry::segment_ratio<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1> > > >,
void>::apply<boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> >,
boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> >, boost::geometry::detail::no_rescale_policy,
boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, boost::geometry::cs::cartesian> >' requested
here
intersection_return_type is = policy::apply(segment1, segment2,
^
/usr/include/boost/geometry/algorithms/intersection.hpp:51:12: note: in instantiation of function template specialization
'boost::geometry::detail::intersection::intersection_segment_segment_point<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational,
1>, boost::geometry::cs::cartesian>
>::apply<boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> >,
boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> >, boost::geometry::detail::no_rescale_policy,
std::back_insert_iterator<std::vector<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian>, std::allocator<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational,
1>, boost::geometry::cs::cartesian> > > >, boost::geometry::strategy_intersection<boost::geometry::cartesian_tag,
boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> >,
boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> >, boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian>, boost::geometry::detail::no_rescale_policy, void> >' requested here
>::apply(geometry1, geometry2, robust_policy, std::back_inserter(geometry_out), strategy);
^
/usr/include/boost/geometry/algorithms/intersection.hpp:148:12: note: in instantiation of function template specialization
'boost::geometry::dispatch::intersection<boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational,
1>, boost::geometry::cs::cartesian> >,
boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> >, boost::geometry::segment_tag, boost::geometry::segment_tag, false>::apply<boost::geometry::detail::no_rescale_policy,
std::vector<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>, boost::geometry::cs::cartesian>,
std::allocator<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> > >, boost::geometry::strategy_intersection<boost::geometry::cartesian_tag,
boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> >,
boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> >, boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian>, boost::geometry::detail::no_rescale_policy, void> >' requested here
>::apply(geometry1, geometry2, robust_policy, geometry_out, strategy());
^
/usr/include/boost/geometry/algorithms/intersection.hpp:308:21: note: in instantiation of function template specialization
'boost::geometry::resolve_variant::intersection<boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational,
1>, boost::geometry::cs::cartesian> >,
boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> >
>::apply<std::vector<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian>, std::allocator<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational,
1>, boost::geometry::cs::cartesian> > > >' requested here
>::template apply
^
boost_geom_intersect.cpp:27:9: note: in instantiation of function template specialization
'boost::geometry::intersection<boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational,
1>, boost::geometry::cs::cartesian> >,
boost::geometry::model::segment<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> >, std::vector<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational,
1>, boost::geometry::cs::cartesian>,
std::allocator<boost::geometry::model::d2::point_xy<boost::multiprecision::number<boost::multiprecision::backends::gmp_rational, 1>,
boost::geometry::cs::cartesian> > > >' requested here
bg::intersection(s1, s2, ip); // Doesn't compile
^
1 error generated.
Boost Geometry is getting confused by the proxy types returned from expression templates, where it is expecting the concrete numeric results: documentation
The Multiprecision library comes in two distinct parts:
An expression-template-enabled front-end number that handles all the operator overloading, expression evaluation optimization, and code reduction.
A selection of back-ends that implement the actual arithmetic operations, and need conform only to the reduced interface requirements of the front-end.
The meta-programming grinds to a halt there.
Fortunately, you can simply use the mpq_rational modified to disable expressions templates:
typedef bm::number<bm::gmp_rational, bm::et_off> my_rational;
This will compile without problems.
Coliru chokes on it, but here it is: http://coliru.stacked-crooked.com/a/232d98bfbb430468
#include <vector>
#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point_xy.hpp>
#include <boost/geometry/geometries/segment.hpp>
#include <boost/geometry/algorithms/intersection.hpp>
#include <boost/multiprecision/gmp.hpp>
#include <boost/multiprecision/number.hpp>
namespace bg = boost::geometry;
namespace bm = boost::multiprecision;
typedef bm::number<bm::gmp_rational, bm::et_off> my_rational;
typedef bg::model::d2::point_xy<my_rational > point;
typedef boost::geometry::model::segment<point> segment;
int main(void)
{
point a(0,0);
point b(1,0);
point c(1,1);
point d(0,1);
segment s1(a,c);
segment s2(b,d);
std::vector<point> ip;
bg::intersection(s1, s2, ip); // Doesn't compile
return 0;
}
Related
I want to use CGAL wrapper for OpenGR to register two point clouds(reference.ply and 1.ply), and I wrote the following simple program (basically copying from the CGAL OpenGR example):
#include <CGAL/Simple_cartesian.h>
#include <CGAL/IO/read_ply_points.h>
#include <CGAL/IO/write_ply_points.h>
#include <CGAL/property_map.h>
#include <CGAL/Aff_transformation_3.h>
#include <CGAL/OpenGR/compute_registration_transformation.h>
#include <fstream>
#include <iostream>
#include <utility>
#include <vector>
typedef CGAL::Simple_cartesian<double> K;
typedef K::Point_3 Point_3;
typedef K::Vector_3 Vector_3;
typedef std::pair<Point_3, Vector_3> Pwn;
typedef CGAL::First_of_pair_property_map<Pwn> Point_map;
typedef CGAL::Second_of_pair_property_map<Pwn> Normal_map;
namespace params = CGAL::parameters;
int main(int argc, const char** argv) {
const char* fname1 = "data/reference.ply";
const char* fname2 = "data/1.ply";
std::vector<Pwn> pwns1, pwns2;
std::ifstream input(fname1);
if (!input ||
!CGAL::read_ply_points(input, std::back_inserter(pwns1),
CGAL::parameters::point_map(CGAL::First_of_pair_property_map<Pwn>()).
normal_map(Normal_map())))
{
std::cerr << "Error: cannot read file " << fname1 << std::endl;
return EXIT_FAILURE;
}
input.close();
input.open(fname2);
if (!input ||
!CGAL::read_ply_points(input, std::back_inserter(pwns2),
CGAL::parameters::point_map(Point_map()).
normal_map(Normal_map())))
{
std::cerr << "Error: cannot read file " << fname2 << std::endl;
return EXIT_FAILURE;
}
input.close();
std::cerr << "Computing registration transformation using OpenGR Super4PCS.." << std::endl;
// First, compute registration transformation using OpenGR Super4PCS
K::Aff_transformation_3 res =
std::get<0>( // get first of pair, which is the transformation
CGAL::OpenGR::compute_registration_transformation
(pwns1, pwns2,
params::point_map(Point_map()).normal_map(Normal_map()),
params::point_map(Point_map()).normal_map(Normal_map()))
);
return EXIT_SUCCESS;
}
The error occurs when I compile the program using Makefile created by cmake, and there are a lot of errors that involves the Eigen library (The error is pretty long):
senyangjiang#senyangjiang-MS-7A38:~/Desktop/dev_compare/cgal_compare/build$ make
Scanning dependencies of target compare
[ 50%] Building CXX object CMakeFiles/compare.dir/compare.cpp.o
/home/senyangjiang/Desktop/dev_compare/OpenGR/3rdparty/Eigen/Eigen/src/Core/Product.h:29:127: error: no type named ‘ReturnType’ in ‘struct Eigen::ScalarBinaryOpTraits<float, double, Eigen::internal::scalar_product_op<float, double> >’
29 | typedef typename ScalarBinaryOpTraits<typename traits<LhsCleaned>::Scalar, typename traits<RhsCleaned>::Scalar>::ReturnType Scalar;
| ^~~~~~
home/senyangjiang/Desktop/dev_compare/OpenGR/3rdparty/Eigen/Eigen/src/Core/DenseBase.h:83:17: error: no members matching ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base {aka Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>}::coeff’ in ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base’ {aka ‘class Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>’}
83 | using Base::coeff;
| ^~~~~
/home/senyangjiang/Desktop/dev_compare/OpenGR/3rdparty/Eigen/Eigen/src/Core/DenseBase.h:84:17: error: no members matching ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base {aka Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>}::coeffByOuterInner’ in ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base’ {aka ‘class Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>’}
84 | using Base::coeffByOuterInner;
| ^~~~~~~~~~~~~~~~~
/home/senyangjiang/Desktop/dev_compare/OpenGR/3rdparty/Eigen/Eigen/src/Core/DenseBase.h:85:26: error: no members matching ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base {aka Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>}::operator()’ in ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base’ {aka ‘class Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>’}
85 | using Base::operator();
| ^
/home/senyangjiang/Desktop/dev_compare/OpenGR/3rdparty/Eigen/Eigen/src/Core/DenseBase.h:86:26: error: no members matching ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base {aka Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>}::operator[]’ in ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base’ {aka ‘class Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>’}
86 | using Base::operator[];
| ^
/home/senyangjiang/Desktop/dev_compare/OpenGR/3rdparty/Eigen/Eigen/src/Core/DenseBase.h:87:17: error: no members matching ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base {aka Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>}::x’ in ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base’ {aka ‘class Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>’}
87 | using Base::x;
| ^
/home/senyangjiang/Desktop/dev_compare/OpenGR/3rdparty/Eigen/Eigen/src/Core/DenseBase.h:88:17: error: no members matching ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base {aka Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>}::y’ in ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base’ {aka ‘class Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>’}
88 | using Base::y;
| ^
/home/senyangjiang/Desktop/dev_compare/OpenGR/3rdparty/Eigen/Eigen/src/Core/DenseBase.h:89:17: error: no members matching ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base {aka Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>}::z’ in ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base’ {aka ‘class Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>’}
89 | using Base::z;
| ^
/home/senyangjiang/Desktop/dev_compare/OpenGR/3rdparty/Eigen/Eigen/src/Core/DenseBase.h:90:17: error: no members matching ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base {aka Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>}::w’ in ‘Eigen::DenseBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0> >::Base’ {aka ‘class Eigen::DenseCoeffsBase<Eigen::Product<Eigen::Ref<const Eigen::Matrix<float, -1, -1> >, Eigen::Homogeneous<Eigen::Matrix<double, 3, 1>, 0>, 0>, 0>’}
90 | using Base::w;
| ^
... more errors like this
/home/senyangjiang/Desktop/dev_compare/OpenGR/3rdparty/Eigen/Eigen/src/Core/AssignEvaluator.h:834:3: error: static assertion failed: YOU_MIXED_DIFFERENT_NUMERIC_TYPES__YOU_NEED_TO_USE_THE_CAST_METHOD_OF_MATRIXBASE_TO_CAST_NUMERIC_TYPES_EXPLICITLY
834 | EIGEN_CHECK_BINARY_COMPATIBILIY(Func,typename ActualDstTypeCleaned::Scalar,typename Src::Scalar);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
make[2]: *** [CMakeFiles/compare.dir/build.make:63: CMakeFiles/compare.dir/compare.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:76: CMakeFiles/compare.dir/all] Error 2
make: *** [Makefile:84: all] Error 2
I can solve the error by changing my code from
typedef CGAL::Simple_cartesian<double> K;
to
typedef CGAL::Simple_cartesian<float> K;
in other words, changing double to float. But I prefer using double due to higher precision, is there any other way to resolve the error?
So I want to use vectors as keys in my unordered_map. I have followed this answer and I have the following
#include <iostream>
#include <cstdlib>
#include <tuple>
#include <unordered_map>
#include <vector>
#include <boost/functional/hash.hpp> /* hash_combine */
template <typename T>
struct vectorHasher{
std::size_t operator()(std::vector<T> &in) const
{
using boost::hash_value;
using boost::hash_combine;
// Start with a hash value of 0
std::size_t seed = 0;
T value;
for (int i=0; i< in.size(); i++)
{
value = static_cast<T>(in[i]);
hash_combine(seed, hash_value(value));
}
return seed;
}
};
int main()
{
typedef std::unordered_map< std::vector<std::size_t>, int, vectorHasher<std::vector<std::size_t> > > map_type;
map_type mymap;
std::vector<size_t> vec (3,100);
mymap[vec] = 1;
return 0;
}
, but I get the following error compiling the code.
In file included from mytest_vectorhasher.cpp:6:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/unordered_map:404:17: error:
no matching function for call to object of type 'const
vectorHasher<std::__1::vector<unsigned long, std::__1::allocator<unsigned long> >
>'
{return static_cast<const _Hash&>(*this)(__x);}
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__hash_table:1976:21: note:
in instantiation of member function
'std::__1::__unordered_map_hasher<std::__1::vector<unsigned long,
std::__1::allocator<unsigned long> >,
std::__1::__hash_value_type<std::__1::vector<unsigned long,
std::__1::allocator<unsigned long> >, int>, vectorHasher<std::__1::vector<unsigned
long, std::__1::allocator<unsigned long> > >, true>::operator()' requested here
size_t __hash = hash_function()(__k);
^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/unordered_map:1443:21: note:
in instantiation of function template specialization
'std::__1::__hash_table<std::__1::__hash_value_type<std::__1::vector<unsigned long,
std::__1::allocator<unsigned long> >, int>,
std::__1::__unordered_map_hasher<std::__1::vector<unsigned long,
std::__1::allocator<unsigned long> >,
std::__1::__hash_value_type<std::__1::vector<unsigned long,
std::__1::allocator<unsigned long> >, int>, vectorHasher<std::__1::vector<unsigned
long, std::__1::allocator<unsigned long> > >, true>,
std::__1::__unordered_map_equal<std::__1::vector<unsigned long,
std::__1::allocator<unsigned long> >,
std::__1::__hash_value_type<std::__1::vector<unsigned long,
std::__1::allocator<unsigned long> >, int>,
std::__1::equal_to<std::__1::vector<unsigned long, std::__1::allocator<unsigned
long> > >, true>,
std::__1::allocator<std::__1::__hash_value_type<std::__1::vector<unsigned long,
std::__1::allocator<unsigned long> >, int> >
>::__emplace_unique_key_args<std::__1::vector<unsigned long,
std::__1::allocator<unsigned long> >, const std::__1::piecewise_construct_t &,
std::__1::tuple<const std::__1::vector<unsigned long, std::__1::allocator<unsigned
long> > &>, std::__1::tuple<> >' requested here
return __table_.__emplace_unique_key_args(__k,
^
mytest_vectorhasher.cpp:41:10: note: in instantiation of member function
'std::__1::unordered_map<std::__1::vector<unsigned long,
std::__1::allocator<unsigned long> >, int, vectorHasher<std::__1::vector<unsigned
long, std::__1::allocator<unsigned long> > >,
std::__1::equal_to<std::__1::vector<unsigned long, std::__1::allocator<unsigned
long> > >, std::__1::allocator<std::__1::pair<const std::__1::vector<unsigned long,
std::__1::allocator<unsigned long> >, int> > >::operator[]' requested here
mymap[vec] = 1;
^
mytest_vectorhasher.cpp:13:17: note: candidate function not viable: no known conversion
from 'const std::__1::vector<unsigned long, std::__1::allocator<unsigned long> >'
to 'std::vector<vector<unsigned long, allocator<unsigned long> > > &' for 1st
argument
std::size_t operator()(std::vector<T> &in) const
^
1 error generated.
Is it something easy that I am messing up? What am I doing wrong?
There are two errors in this example. First, your hasher's operator() parameter should be const.
std::size_t operator()(const std::vector<T> &in) const
// Add const here ^^^^^
Second is you are defining your hashing type as vectorHasher<std::vector<std::size_t> > which would imply that T = std::vector<std::size_t>, meaning that you are trying to instantiate a hasher with std::size_t operator()(const std::vector<std::vector<std::size_t>> &in) const which is too many vectors. Remove the std::vector from your map type declaration like this :
typedef std::unordered_map< std::vector<std::size_t>, int, vectorHasher< std::size_t > > map_type;
// Remove std::vector from this template argument ^^^^^^^^^^^
The problem is you have the wrong parameter for operator(). When you construct the vectorHasher you use
vectorHasher<std::vector<std::size_t>>
Which means T is a
std::vector<std::size_t>
That means your operator() looks like
std::size_t operator()(std::vector<std::vector<std::size_t>> &in) const
Which is not what you want. What you can do is to use T directly like
std::size_t operator()(const T& in) const
Or change the vectorHasher to be
vectorHasher<std::size_t>
There are 2 errors in your code.
1) Since you defined your vectorHasher as
template <typename T>
struct vectorHasher{
std::size_t operator()(std::vector<T> &in) const
{
// ...
}
};
The following template instantiation vectorHasher<std::vector<std::size_t>> expands to:
struct vectorHasher{
std::size_t operator()(std::vector<std::vector<std::size_t>> &in) const
{
// ...
}
};
And, sure enough, std::vector<std::size_t> can't be passed to this function.
Change the instantiation of the template to vectorHasher<std::size_t>.
2) operator() of the struct used for hashing needs to take const value/reference, so you should change the signature of it to:
std::size_t operator()(std::vector<T> const &in) const
Live demo.
I am trying to partition a boost::range::transformed adaptor:
#include <boost/range.hpp>
#include <boost/range/algorithm/partition.hpp>
#include <boost/range/algorithm/transform.hpp>
#include <boost/range/any_range.hpp>
#include <boost/range/adaptor/transformed.hpp>
using boost::adaptors::transformed;
void foo()
{
boost::any_range<int,
boost::forward_traversal_tag,
int&,
std::ptrdiff_t> r;
auto t = r | transformed( [](int) {return 0;} );
auto p = boost::range::partition(t, [](int) {return true;} );
std::vector<int> v;
auto t2 = r | transformed( [](int) {return 0;} );
auto p2 = boost::range::partition(t2, [](int) {return true;} );
}
The compiler complains for p1 and p2 that it cannot find a function __partition which accepts a boost::iterators__transform_iterator. The complete error message is
In file included from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/algorithm:62:0,
from /tmp/boost_1_59_0/boost/iterator/iterator_concepts.hpp:29,
from /tmp/boost_1_59_0/boost/range/concepts.hpp:20,
from /tmp/boost_1_59_0/boost/range/size_type.hpp:20,
from /tmp/boost_1_59_0/boost/range/size.hpp:21,
from /tmp/boost_1_59_0/boost/range/functions.hpp:20,
from /tmp/boost_1_59_0/boost/range.hpp:18,
from range_partition.cpp:1:
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/stl_algo.h: In instantiation of ‘_BIter std::partition(_BIter, _BIter, _Predicate) [with _BIter = boost::iterators::transform_iterator<boost::range_detail::default_constructible_unary_fn_wrapper<foo()::<lambda(int)>, int>, boost::range_detail::any_iterator<int, boost::iterators::forward_traversal_tag, int&, long int, boost::any_iterator_buffer<64ul> >, boost::iterators::use_default, boost::iterators::use_default>; _Predicate = foo()::<lambda(int)>]’:
/tmp/boost_1_59_0/boost/range/algorithm/partition.hpp:34:65: required from ‘typename boost::range_iterator<C>::type boost::range::partition(ForwardRange&, UnaryPredicate) [with ForwardRange = boost::range_detail::transformed_range<foo()::<lambda(int)>, boost::range_detail::any_range<int, boost::iterators::forward_traversal_tag, int&, long int> >; UnaryPredicate = foo()::<lambda(int)>; typename boost::range_iterator<C>::type = boost::iterators::transform_iterator<boost::range_detail::default_constructible_unary_fn_wrapper<foo()::<lambda(int)>, int>, boost::range_detail::any_iterator<int, boost::iterators::forward_traversal_tag, int&, long int, boost::any_iterator_buffer<64ul> >, boost::iterators::use_default, boost::iterators::use_default>]’
range_partition.cpp:22:66: required from here
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/stl_algo.h:4509:43: error: no matching function for call to ‘__partition(boost::iterators::transform_iterator<boost::range_detail::default_constructible_unary_fn_wrapper<foo()::<lambda(int)>, int>, boost::range_detail::any_iterator<int, boost::iterators::forward_traversal_tag, int&, long int, boost::any_iterator_buffer<64ul> >, boost::iterators::use_default, boost::iterators::use_default>&, boost::iterators::transform_iterator<boost::range_detail::default_constructible_unary_fn_wrapper<foo()::<lambda(int)>, int>, boost::range_detail::any_iterator<int, boost::iterators::forward_traversal_tag, int&, long int, boost::any_iterator_buffer<64ul> >, boost::iterators::use_default, boost::iterators::use_default>&, foo()::<lambda(int)>&, std::__iterator_traits<boost::iterators::transform_iterator<boost::range_detail::default_constructible_unary_fn_wrapper<foo()::<lambda(int)>, int>, boost::range_detail::any_iterator<int, boost::iterators::forward_traversal_tag, int&, long int, boost::any_iterator_buffer<64ul> >, boost::iterators::use_default, boost::iterators::use_default>, true>::iterator_category)’
std::__iterator_category(__first));
^
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/stl_algo.h:4509:43: note: candidates are:
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/stl_algo.h:1462:5: note: template<class _ForwardIterator, class _Predicate> _ForwardIterator std::__partition(_ForwardIterator, _ForwardIterator, _Predicate, std::forward_iterator_tag)
__partition(_ForwardIterator __first, _ForwardIterator __last,
^
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/stl_algo.h:1462:5: note: template argument deduction/substitution failed:
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/stl_algo.h:4509:43: note: cannot convert ‘std::__iterator_category<boost::iterators::transform_iterator<boost::range_detail::default_constructible_unary_fn_wrapper<foo()::<lambda(int)>, int>, boost::range_detail::any_iterator<int, boost::iterators::forward_traversal_tag, int&, long int, boost::any_iterator_buffer<64ul> >, boost::iterators::use_default, boost::iterators::use_default> >((*(const boost::iterators::transform_iterator<boost::range_detail::default_constructible_unary_fn_wrapper<foo()::<lambda(int)>, int>, boost::range_detail::any_iterator<int, boost::iterators::forward_traversal_tag, int&, long int, boost::any_iterator_buffer<64ul> >, boost::iterators::use_default, boost::iterators::use_default>*)(& __first)))’ (type ‘std::__iterator_traits<boost::iterators::transform_iterator<boost::range_detail::default_constructible_unary_fn_wrapper<foo()::<lambda(int)>, int>, boost::range_detail::any_iterator<int, boost::iterators::forward_traversal_tag, int&, long int, boost::any_iterator_buffer<64ul> >, boost::iterators::use_default, boost::iterators::use_default>, true>::iterator_category {aka boost::iterators::detail::iterator_category_with_traversal<std::input_iterator_tag, boost::iterators::forward_traversal_tag>}’) to type ‘std::forward_iterator_tag’
std::__iterator_category(__first));
^
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/stl_algo.h:1487:5: note: template<class _BidirectionalIterator, class _Predicate> _BidirectionalIterator std::__partition(_BidirectionalIterator, _BidirectionalIterator, _Predicate, std::bidirectional_iterator_tag)
__partition(_BidirectionalIterator __first, _BidirectionalIterator __last,
^
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/stl_algo.h:1487:5: note: template argument deduction/substitution failed:
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/stl_algo.h:4509:43: note: cannot convert ‘std::__iterator_category<boost::iterators::transform_iterator<boost::range_detail::default_constructible_unary_fn_wrapper<foo()::<lambda(int)>, int>, boost::range_detail::any_iterator<int, boost::iterators::forward_traversal_tag, int&, long int, boost::any_iterator_buffer<64ul> >, boost::iterators::use_default, boost::iterators::use_default> >((*(const boost::iterators::transform_iterator<boost::range_detail::default_constructible_unary_fn_wrapper<foo()::<lambda(int)>, int>, boost::range_detail::any_iterator<int, boost::iterators::forward_traversal_tag, int&, long int, boost::any_iterator_buffer<64ul> >, boost::iterators::use_default, boost::iterators::use_default>*)(& __first)))’ (type ‘std::__iterator_traits<boost::iterators::transform_iterator<boost::range_detail::default_constructible_unary_fn_wrapper<foo()::<lambda(int)>, int>, boost::range_detail::any_iterator<int, boost::iterators::forward_traversal_tag, int&, long int, boost::any_iterator_buffer<64ul> >, boost::iterators::use_default, boost::iterators::use_default>, true>::iterator_category {aka boost::iterators::detail::iterator_category_with_traversal<std::input_iterator_tag, boost::iterators::forward_traversal_tag>}’) to type ‘std::bidirectional_iterator_tag’
std::__iterator_category(__first));
I am quite lost and don't see a solution for this. Any help would be greatly appreciated.
The transformed range is not a mutable sequence.
You cannot partition such a range (because you can't swap elements).
You can look at partition_copy, in which case you should have a destination iterator to receive the partitioned range.
With a bit of work, it seems like you should be able to craft a Boost Range style Adaptor out of this too (see docs on extending: http://www.boost.org/doc/libs/1_59_0/libs/range/doc/html/range/reference/extending/method_3.html) in case you really insist on having partitioned like in the first example.
Sample
Here's what I'd suggest as a 'halfway' solution: convenient without too much effort (c++11)
Live On Coliru
#include <boost/range.hpp>
#include <boost/range/algorithm.hpp>
#include <boost/range/algorithm_ext.hpp>
#include <boost/range/any_range.hpp>
#include <boost/range/adaptors.hpp>
using boost::adaptors::transformed;
namespace {
// convenience wrapper
template <typename Range, typename Predicate, typename OutIt1, typename OutIt2>
std::pair<OutIt1, OutIt2> partition_copy(Range const& range, OutIt1 out1, OutIt2 out2, Predicate&& predicate) {
return std::partition_copy(
boost::begin(range), boost::end(range),
out1, out2,
std::forward<Predicate>(predicate));
}
}
#include <iostream>
int main()
{
std::vector<int> demo { 1,2,7,3,-9,42 };
std::vector<int> even, odd;
partition_copy(
demo | transformed( [](int i) {return i+1;} ),
back_inserter(even), back_inserter(odd),
[] (int i) { return 0 == i%2; }
);
// output
boost::copy(even, std::ostream_iterator<int>(std::cout << "even : ", " "));
boost::copy(odd, std::ostream_iterator<int>(std::cout << "\nodd : ", " "));
}
Prints
even : 2 8 4 -8
odd : 3 43
Consider this:
#include <iostream>
#include <map>
#include <string>
#include <boost/assign/list_of.hpp>
using boost::assign::map_list_of;
const std::map<int, std::map<int, char> > test = map_list_of
(100, map_list_of
(1, 'a')
(2, 'b')
)
(101, map_list_of
(1, 'c')
(2, 'd')
)
;
int main()
{
std::cout << test.find(101)->second.find(2)->second << "\n";
}
I wanted the result to be a program that, when executed, outputs d.
Instead, I get this:
$ clang++ -std=c++03 -O2 -Wall -pedantic -pthread main.cpp
In file included from main.cpp:1:
In file included from /usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/iostream:39:
In file included from /usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/ostream:38:
In file included from /usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/ios:40:
In file included from /usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/char_traits.h:39:
In file included from /usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_algobase.h:64:
/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_pair.h:119:22: error: call to constructor of 'std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > >' is ambiguous
: first(__p.first), second(__p.second) { }
^ ~~~~~~~~~~
/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_tree.h:1843:29: note: in instantiation of function template specialization 'std::pair<const int, std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > > >::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > >' requested here
_M_insert_unique_(end(), *__first);
^
/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_map.h:255:16: note: in instantiation of function template specialization 'std::_Rb_tree<int, std::pair<const int, std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > > >, std::_Select1st<std::pair<const int, std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > > > >, std::less<int>, std::allocator<std::pair<const int, std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > > > > >::_M_insert_unique<std::_Deque_iterator<std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > >, std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > > &, std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > > *> >' requested here
{ _M_t._M_insert_unique(__first, __last); }
^
/usr/local/include/boost/assign/list_of.hpp:163:20: note: in instantiation of function template specialization 'std::map<int, std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > >, std::less<int>, std::allocator<std::pair<const int, std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > > > > >::map<std::_Deque_iterator<std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > >, std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > > &, std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > > *> >' requested here
return Container( begin(), end() );
^
/usr/local/include/boost/assign/list_of.hpp:142:20: note: in instantiation of function template specialization 'boost::assign_detail::converter<boost::assign_detail::generic_list<std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > > >, std::_Deque_iterator<std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > >, std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > > &, std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > > *> >::convert<std::map<int, std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > >, std::less<int>, std::allocator<std::pair<const int, std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > > > > > >' requested here
return convert<Container>( c, tag_type() );
^
/usr/local/include/boost/assign/list_of.hpp:436:49: note: in instantiation of function template specialization 'boost::assign_detail::converter<boost::assign_detail::generic_list<std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > > >, std::_Deque_iterator<std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > >, std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > > &, std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > > *> >::convert_to_container<std::map<int, std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > >, std::less<int>, std::allocator<std::pair<const int, std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > > > > > >' requested here
return this-> BOOST_NESTED_TEMPLATE convert_to_container<Container>();
^
main.cpp:7:50: note: in instantiation of function template specialization 'boost::assign_detail::generic_list<std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> > > >::operator map<std::map<int, std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > >, std::less<int>, std::allocator<std::pair<const int, std::map<int, char, std::less<int>, std::allocator<std::pair<const int, char> > > > > > >' requested here
const std::map<int, std::map<int, char> > test = map_list_of
^
/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_map.h:171:7: note: candidate constructor
map(const _Compare& __comp,
^
/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_map.h:182:7: note: candidate constructor
map(const map& __x)
^
1 error generated.
(similar results under GCC)
How can I resolve this?
I get a similar error even if I use std::map<int, char>(map_list_of(...)) instead of map_list_of(...) for those inner maps.
C++03 defines two constructors for map that can be called with one argument [lib.map]p2:
explicit map(const Compare& comp = Compare(),
const Allocator& = Allocator());
// [...]
map(const map<Key,T,Compare,Allocator>& x);
boost's map_list_of creates an object of a generic_list class template instantiation, from the recent SVN:
template< class Key, class T >
inline assign_detail::generic_list< std::pair
<
BOOST_DEDUCED_TYPENAME assign_detail::assign_decay<Key>::type,
BOOST_DEDUCED_TYPENAME assign_detail::assign_decay<T>::type
> >
map_list_of( const Key& k, const T& t )
Where the primary generic_list template contains the following conversion operator:
template< class Container >
operator Container() const
{
return this-> BOOST_NESTED_TEMPLATE convert_to_container<Container>();
}
Both map constructors are viable, as this operator allows conversion to both map and Compare. As far as I know, you cannot SFINAE-constrain a conversion operator in C++03.
The map is constructed explicitly when inserting a new node in the outer map. A pair of iterators is used to iterate over the inner generic_list to construct the outer map. Dereferencing this iterator yields a std::pair<int, boost::assign_detail::generic_list<std::pair<int, char> >. The node (value) type of the outer map is std::pair<int const, std::map<int, char> >.
Therefore, the compiler tries to construct the latter type from the former. In C++03, this pair constructor is not SFINAE-constrained, since that's not possible in C++03. [lib.pairs]p1
template<class U, class V> pair(const pair<U, V> &p);
libstdc++ implements this as follows:
template<class _U1, class _U2>
pair(const pair<_U1, _U2>& __p)
: first(__p.first), second(__p.second) { }
I'm not entirely sure if that's compliant, since [lib.pairs]p4
Effects: Initializes members from the corresponding members of the argument, performing implicit conversions as needed.
(But, as I said, SFINAE on ctors cannot be implemented in C++03.)
In C++11 and 14, this also fails, but for a different reason. Here, the pair constructors are SFINAE-constrained. But the constrain requires implicit convertibility (is_convertible), while the program has UB if the target pair of types cannot be constructed from the sources (is_constructible). I've written a bit more about this issue in another SO answer. Interestingly, a proposed solution N4387 to the issue mentioned in that other question says:
It should be noted here, that for the general case the
std::is_constructible<T, U>::value requirement for the non-explicit
constructor which is constrained on std::is_convertible<U, T>::value
is not redundant, because it is possible to create types that can be
copy-initialized but not direct-initialized
This is exactly the case we run into here: A map can be copy-initialized from a generic_list, since this makes the explicit constructor non-viable. But a map cannot be direct-initialized from generic_list, since this makes the conversion ambiguous.
As far as I can see, N4387 does not solve the problem in the OP. On the other hand, with uniform initialization, we have an alternative to map_list_of. And we can SFINAE-constrain conversion operators since C++11.
One solution is to eliminate the explicit constructor by only allowing implicit conversions:
template<typename T> T implicit_cast(T t) { return t; }
implicit_cast<InnerMap>( map_list_of(1, 'a')(2, 'b') )
But there's a more direct way: simply use the convert_to_container member function of generic_list's base class converter (also a class template):
map_list_of(1, 'a')(2, 'b').convert_to_container<InnerMap>()
This is a simplified version of some code I wrote:
#include <iostream>
#include <boost/mpl/vector.hpp>
#include <boost/mpl/contains.hpp>
#include <boost/mpl/placeholders.hpp>
#include <boost/fusion/include/filter_if.hpp>
#include <boost/fusion/include/for_each.hpp>
#include <boost/fusion/include/map.hpp>
#include <boost/fusion/include/pair.hpp>
#include <boost/fusion/include/io.hpp>
namespace ids{
struct a0{};
struct a1{};
struct a2{};
struct a3{};
};
typedef boost::fusion::map< boost::fusion::pair<ids::a0,int>
, boost::fusion::pair<ids::a1,double>
, boost::fusion::pair<ids::a2,char>
, boost::fusion::pair<ids::a3,long> > map_type;
typedef boost::mpl::vector<ids::a0,ids::a3> vec_ids_type;
template <typename T>
struct get_first
{
typedef typename T::first_type type;
};
typedef boost::fusion::result_of::filter_if<
map_type
, boost::mpl::contains<
vec_ids_type
, get_first<
boost::mpl::placeholders::_1
>
>
>::type view_type;
struct SetToZero
{
template <typename Field>
void operator()(Field & field) const
{
field.second = 0;
}
};
int main() {
map_type m( boost::fusion::make_pair<ids::a0>(1)
, boost::fusion::make_pair<ids::a1>(2.0)
, boost::fusion::make_pair<ids::a2>('a')
, boost::fusion::make_pair<ids::a3>(4)
);
std::cout << m << std::endl;
view_type v(m);
std::cout << v << std::endl;
boost::fusion::for_each(v,SetToZero());
std::cout << m << std::endl;
}
I want to use view_type to set to zero some elements in an instance of map_type. If the key of one element in map_type is in vec_ids_type, then the data corresponding to that element has to be set to zero, which is done by calling the functor SetToZero. For all this to work, T is meant to be a fusion::pair when get_first<T> is instantiated.
This code compiles and runs perfectly using boost 1.40 and g++ 4.4.3. However I tried to recompile my code using newer versions of boost and g++ and I get compilation errors. Although I think it has to do with boost and not with the compiler, I'll also mention the g++ version. First I tried using boost 1.48.0.2 and g++ 4.6.3, then I tried using boost 1.49.0.1 and g++ 4.7.2. Both attempts failed, giving very similar (if not the same) compilation errors. The error messages are:
tests.cpp: In instantiation of ‘struct get_first<ids::a0>’:
/usr/include/boost/mpl/aux_/has_type.hpp:20:1: required from ‘struct boost::mpl::aux::has_type<get_first<ids::a0>, mpl_::bool_<true> >’
/usr/include/boost/mpl/aux_/preprocessed/gcc/quote.hpp:32:36: required from ‘struct boost::mpl::quote1<get_first, mpl_::void_>::apply<ids::a0>’
/usr/include/boost/mpl/aux_/preprocessed/gcc/apply_wrap.hpp:36:8: required from ‘struct boost::mpl::apply_wrap1<boost::mpl::quote1<get_first, mpl_::void_>, ids::a0>’
/usr/include/boost/mpl/aux_/preprocessed/gcc/bind.hpp:144:21: [ skipping 16 instantiation contexts ]
/usr/include/boost/mpl/aux_/preprocessed/gcc/iter_fold_if_impl.hpp:101:135: required from ‘struct boost::mpl::aux::iter_fold_if_impl<boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l>, void, mpl_::arg<1>, boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> >, 0>, mpl_::na, boost::mpl::always<mpl_::bool_<false> > >’
/usr/include/boost/mpl/iter_fold_if.hpp:81:12: required from ‘struct boost::mpl::iter_fold_if<boost::mpl::vector<ids::a0, ids::a3>, void, mpl_::arg<1>, boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, mpl_::na, mpl_::na>::result_’
/usr/include/boost/mpl/iter_fold_if.hpp:104:11: required from ‘struct boost::mpl::iter_fold_if<boost::mpl::vector<ids::a0, ids::a3>, void, mpl_::arg<1>, boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, mpl_::na, mpl_::na>’
/usr/include/boost/mpl/find_if.hpp:39:17: required from ‘struct boost::mpl::find_if<boost::mpl::vector<ids::a0, ids::a3>, boost::mpl::same_as<get_first<mpl_::arg<1> > > >’
/usr/include/boost/mpl/find.hpp:28:8: required from ‘struct boost::mpl::find<boost::mpl::vector<ids::a0, ids::a3>, get_first<mpl_::arg<1> > >’
/usr/include/boost/mpl/aux_/contains_impl.hpp:33:54: required from ‘struct boost::mpl::contains_impl<boost::mpl::aux::vector_tag>::apply<boost::mpl::vector<ids::a0, ids::a3>, get_first<mpl_::arg<1> > >’
/usr/include/boost/mpl/contains.hpp:30:8: required from ‘struct boost::mpl::contains<boost::mpl::vector<ids::a0, ids::a3>, get_first<mpl_::arg<1> > >’
tests.cpp:70:16: required from here
tests.cpp:37:34: error: no type named ‘first_type’ in ‘struct ids::a0’
In file included from /usr/include/boost/mpl/assert.hpp:17:0,
from /usr/include/boost/mpl/aux_/na_assert.hpp:23,
from /usr/include/boost/mpl/arg.hpp:25,
from /usr/include/boost/mpl/placeholders.hpp:24,
from /usr/include/boost/mpl/apply.hpp:24,
from /usr/include/boost/mpl/aux_/iter_apply.hpp:17,
from /usr/include/boost/mpl/aux_/find_if_pred.hpp:14,
from /usr/include/boost/mpl/find_if.hpp:17,
from /usr/include/boost/mpl/find.hpp:17,
from /usr/include/boost/mpl/aux_/contains_impl.hpp:20,
from /usr/include/boost/mpl/contains.hpp:20,
from tests.cpp:12:
/usr/include/boost/mpl/not.hpp: In instantiation of ‘struct boost::mpl::not_<boost::mpl::aux::iter_apply1<boost::mpl::same_as<get_first<mpl_::arg<1> > >, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> > >’:
/usr/include/boost/mpl/aux_/nested_type_wknd.hpp:26:31: required from ‘struct boost::mpl::aux::nested_type_wknd<boost::mpl::apply1<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> > >’
/usr/include/boost/mpl/aux_/preprocessed/gcc/and.hpp:23:8: required from ‘struct boost::mpl::aux::and_impl<true, boost::mpl::apply1<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> >, mpl_::bool_<true>, mpl_::bool_<true>, mpl_::bool_<true> >’
/usr/include/boost/mpl/aux_/preprocessed/gcc/and.hpp:48:8: required from ‘struct boost::mpl::and_<boost::mpl::not_<boost::is_same<boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> > >, boost::mpl::apply1<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> >, mpl_::bool_<true>, mpl_::bool_<true>, mpl_::bool_<true> >’
/usr/include/boost/mpl/iter_fold_if.hpp:40:58: required from ‘struct boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> >::apply<void, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> >’
/usr/include/boost/mpl/aux_/preprocessed/gcc/apply_wrap.hpp:46:8: required from ‘struct boost::mpl::apply_wrap2<boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> >, 0>, void, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> >’
/usr/include/boost/mpl/aux_/preprocessed/gcc/apply.hpp:67:8: [ skipping 4 instantiation contexts ]
/usr/include/boost/mpl/iter_fold_if.hpp:104:11: required from ‘struct boost::mpl::iter_fold_if<boost::mpl::vector<ids::a0, ids::a3>, void, mpl_::arg<1>, boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, mpl_::na, mpl_::na>’
/usr/include/boost/mpl/find_if.hpp:39:17: required from ‘struct boost::mpl::find_if<boost::mpl::vector<ids::a0, ids::a3>, boost::mpl::same_as<get_first<mpl_::arg<1> > > >’
/usr/include/boost/mpl/find.hpp:28:8: required from ‘struct boost::mpl::find<boost::mpl::vector<ids::a0, ids::a3>, get_first<mpl_::arg<1> > >’
/usr/include/boost/mpl/aux_/contains_impl.hpp:33:54: required from ‘struct boost::mpl::contains_impl<boost::mpl::aux::vector_tag>::apply<boost::mpl::vector<ids::a0, ids::a3>, get_first<mpl_::arg<1> > >’
/usr/include/boost/mpl/contains.hpp:30:8: required from ‘struct boost::mpl::contains<boost::mpl::vector<ids::a0, ids::a3>, get_first<mpl_::arg<1> > >’
tests.cpp:70:16: required from here
/usr/include/boost/mpl/not.hpp:39:8: error: ‘value’ is not a member of ‘boost::mpl::aux::nested_type_wknd<boost::mpl::aux::iter_apply1<boost::mpl::same_as<get_first<mpl_::arg<1> > >, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> > >’
In file included from /usr/include/boost/mpl/aux_/include_preprocessed.hpp:37:0,
from /usr/include/boost/mpl/and.hpp:42,
from /usr/include/boost/mpl/logical.hpp:18,
from /usr/include/boost/mpl/iter_fold_if.hpp:19,
from /usr/include/boost/mpl/find_if.hpp:19,
from /usr/include/boost/mpl/find.hpp:17,
from /usr/include/boost/mpl/aux_/contains_impl.hpp:20,
from /usr/include/boost/mpl/contains.hpp:20,
from tests.cpp:12:
/usr/include/boost/mpl/aux_/preprocessed/gcc/and.hpp: In instantiation of ‘struct boost::mpl::aux::and_impl<true, boost::mpl::apply1<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> >, mpl_::bool_<true>, mpl_::bool_<true>, mpl_::bool_<true> >’:
/usr/include/boost/mpl/aux_/preprocessed/gcc/and.hpp:48:8: required from ‘struct boost::mpl::and_<boost::mpl::not_<boost::is_same<boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> > >, boost::mpl::apply1<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> >, mpl_::bool_<true>, mpl_::bool_<true>, mpl_::bool_<true> >’
/usr/include/boost/mpl/iter_fold_if.hpp:40:58: required from ‘struct boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> >::apply<void, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> >’
/usr/include/boost/mpl/aux_/preprocessed/gcc/apply_wrap.hpp:46:8: required from ‘struct boost::mpl::apply_wrap2<boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> >, 0>, void, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> >’
/usr/include/boost/mpl/aux_/preprocessed/gcc/apply.hpp:67:8: required from ‘struct boost::mpl::apply2<boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> >, 0>, void, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> >’
/usr/include/boost/mpl/aux_/preprocessed/gcc/iter_fold_if_impl.hpp:62:63: required from ‘struct boost::mpl::aux::iter_fold_if_forward_step<boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l>, void, mpl_::arg<1>, boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> >, 0> >’
/usr/include/boost/mpl/aux_/preprocessed/gcc/iter_fold_if_impl.hpp:101:135: [ skipping 2 instantiation contexts ]
/usr/include/boost/mpl/iter_fold_if.hpp:104:11: required from ‘struct boost::mpl::iter_fold_if<boost::mpl::vector<ids::a0, ids::a3>, void, mpl_::arg<1>, boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, mpl_::na, mpl_::na>’
/usr/include/boost/mpl/find_if.hpp:39:17: required from ‘struct boost::mpl::find_if<boost::mpl::vector<ids::a0, ids::a3>, boost::mpl::same_as<get_first<mpl_::arg<1> > > >’
/usr/include/boost/mpl/find.hpp:28:8: required from ‘struct boost::mpl::find<boost::mpl::vector<ids::a0, ids::a3>, get_first<mpl_::arg<1> > >’
/usr/include/boost/mpl/aux_/contains_impl.hpp:33:54: required from ‘struct boost::mpl::contains_impl<boost::mpl::aux::vector_tag>::apply<boost::mpl::vector<ids::a0, ids::a3>, get_first<mpl_::arg<1> > >’
/usr/include/boost/mpl/contains.hpp:30:8: required from ‘struct boost::mpl::contains<boost::mpl::vector<ids::a0, ids::a3>, get_first<mpl_::arg<1> > >’
tests.cpp:70:16: required from here
/usr/include/boost/mpl/aux_/preprocessed/gcc/and.hpp:23:8: error: ‘value’ is not a member of ‘boost::mpl::aux::nested_type_wknd<boost::mpl::apply1<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> > >’
In file included from /usr/include/boost/mpl/aux_/include_preprocessed.hpp:37:0,
from /usr/include/boost/mpl/aux_/iter_fold_if_impl.hpp:32,
from /usr/include/boost/mpl/iter_fold_if.hpp:25,
from /usr/include/boost/mpl/find_if.hpp:19,
from /usr/include/boost/mpl/find.hpp:17,
from /usr/include/boost/mpl/aux_/contains_impl.hpp:20,
from /usr/include/boost/mpl/contains.hpp:20,
from tests.cpp:12:
/usr/include/boost/mpl/aux_/preprocessed/gcc/iter_fold_if_impl.hpp: In instantiation of ‘struct boost::mpl::aux::iter_fold_if_forward_step<boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l>, void, mpl_::arg<1>, boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> >, 0> >’:
/usr/include/boost/mpl/aux_/preprocessed/gcc/iter_fold_if_impl.hpp:101:135: required from ‘struct boost::mpl::aux::iter_fold_if_impl<boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l>, void, mpl_::arg<1>, boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> >, 0>, mpl_::na, boost::mpl::always<mpl_::bool_<false> > >’
/usr/include/boost/mpl/iter_fold_if.hpp:81:12: required from ‘struct boost::mpl::iter_fold_if<boost::mpl::vector<ids::a0, ids::a3>, void, mpl_::arg<1>, boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, mpl_::na, mpl_::na>::result_’
/usr/include/boost/mpl/iter_fold_if.hpp:104:11: required from ‘struct boost::mpl::iter_fold_if<boost::mpl::vector<ids::a0, ids::a3>, void, mpl_::arg<1>, boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, mpl_::na, mpl_::na>’
/usr/include/boost/mpl/find_if.hpp:39:17: required from ‘struct boost::mpl::find_if<boost::mpl::vector<ids::a0, ids::a3>, boost::mpl::same_as<get_first<mpl_::arg<1> > > >’
/usr/include/boost/mpl/find.hpp:28:8: required from ‘struct boost::mpl::find<boost::mpl::vector<ids::a0, ids::a3>, get_first<mpl_::arg<1> > >’
/usr/include/boost/mpl/aux_/contains_impl.hpp:33:54: required from ‘struct boost::mpl::contains_impl<boost::mpl::aux::vector_tag>::apply<boost::mpl::vector<ids::a0, ids::a3>, get_first<mpl_::arg<1> > >’
/usr/include/boost/mpl/contains.hpp:30:8: required from ‘struct boost::mpl::contains<boost::mpl::vector<ids::a0, ids::a3>, get_first<mpl_::arg<1> > >’
tests.cpp:70:16: required from here
/usr/include/boost/mpl/aux_/preprocessed/gcc/iter_fold_if_impl.hpp:62:63: error: no type named ‘type’ in ‘struct boost::mpl::apply2<boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> >, 0>, void, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> >’
/usr/include/boost/mpl/aux_/preprocessed/gcc/iter_fold_if_impl.hpp:65:78: error: no type named ‘type’ in ‘struct boost::mpl::apply2<boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::mpl::aux::find_if_pred<boost::mpl::same_as<get_first<mpl_::arg<1> > > >, 0>, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 2l> >, 0>, void, boost::mpl::v_iter<boost::mpl::vector<ids::a0, ids::a3>, 0l> >’
tests.cpp: In instantiation of ‘struct get_first<mpl_::arg<1> >’:
tests.cpp:70:16: required from here
tests.cpp:37:34: error: no type named ‘first_type’ in ‘struct mpl_::arg<1>’
From the very first line of the error messages there is something completely unexpected for me tests.cpp: In instantiation of ‘struct get_first<ids::a0>’. This should not happen because get_first should only be instantiated using elements of map_type, i.e. fusion::pair. I really don't understand why this is happening.
As I said, it works perfectly with boost 1.40, and it makes a lot of sense for me as it is written now, so I really don't see where the error is. My only guess is that something might have changed in the newer versions of fusion or mpl that is causing this. Actually I checked the change logs of Boost.Fusion and Boost and something related to fusion views have been modified/added. Maybe a bug? or, Am I missing something? why it does not work with the newer versions of boost that I tried?
thanks in advance!
Using:
typedef boost::fusion::result_of::filter_if<
map_type
,
boost::mpl::lambda<
boost::mpl::contains<
vec_ids_type
,
get_first<
boost::mpl::_1
>
>
>::type
>::type view_type;
Seems to make it work as you can see here. Currently LiveWorkspace uses boost 1.53.0.