从 python 调用 boost rtree
Calling boost rtree from python
我正在尝试调整此 boost rtree example 以便 python 调用 c++ 库。这是我第一次尝试从 python 调用 c++。我在 ubuntu 16.04.7 LTS 上使用 cppyy 1.8.5（python 版本 3.6.7）和 boost rtree header-only 库（boost 版本 1.58）。这是我到目前为止的代码。
import cppyy
cppyy.set_debug()
import cppyy.ll
cppyy.ll.set_signals_as_exception(True)
cppyy.add_include_path('/usr/include')
cppyy.include('boost/geometry.hpp')
cppyy.include('boost/geometry/geometries/point.hpp')
cppyy.include('boost/geometry/geometries/box.hpp')
cppyy.include('boost/geometry/index/rtree.hpp')
cppyy.include('vector')
cppyy.include('iostream')
cppyy.include('boost/foreach.hpp')
cpp = cppyy.gbl
std = cpp.std
bg = cpp.boost.geometry
bgi = cpp.boost.geometry.index
point = bg.model.point[float, 2, bg.cs.cartesian]
box = bg.model.box[point]
value = std.pair[box, 'unsigned']
rtree = bgi.rtree[value, bgi.quadratic(16)]
for i in range(10):
b = box(point(i + 0.0, i + 0.0), point(i + 0.5, i + 0.5))
print(bg.wkt[box](b))
with cppyy.ll.signals_as_exception():
rtree.insert(std.make_pair(b, i))
在 for 循环中，框已创建，但 rtree.insert() 调用产生错误。
$ python try_cppyy_rtree.py
TClass::GetClass: Header Parsing - The representation of __cppyy_internal was not found in the type system. A lookup in the interpreter is about to be tried: this can cause parsing. This can be avoided selecting __cppyy_internal in the linkdef/selection file.
...<trimmed>...
TClass::GetClass: Header Parsing - The representation of boost::geometry::wkt_manipulator<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> > > was not found in the type system. A lookup in the interpreter is about to be tried: this can cause parsing. This can be avoided selecting boost::geometry::wkt_manipulator<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> > > in the linkdef/selection file.
POLYGON((0 0,0 0.5,0.5 0.5,0.5 0,0 0))
TClass::GetClass: Header Parsing - The representation of std::make_pair was not found in the type system. A lookup in the interpreter is about to be tried: this can cause parsing. This can be avoided selecting std::make_pair in the linkdef/selection file.
TClass::GetClass: Header Parsing - The representation of std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int> was not found in the type system. A lookup in the interpreter is about to be tried: this can cause parsing. This can be avoided selecting std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int> in the linkdef/selection file.
TClass::GetClass: Header Parsing - The representation of std::__pair_base<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int> was not found in the type system. A lookup in the interpreter is about to be tried: this can cause parsing. This can be avoided selecting std::__pair_base<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int> in the linkdef/selection file.
In file included from input_line_19:1:
In file included from /usr/include/boost/geometry.hpp:17:
In file included from /usr/include/boost/geometry/geometry.hpp:43:
In file included from /usr/include/boost/geometry/core/radian_access.hpp:28:
In file included from /usr/include/boost/geometry/util/math.hpp:28:
In file included from /usr/include/boost/math/constants/constants.hpp:18:
In file included from /usr/include/boost/lexical_cast.hpp:30:
In file included from /usr/include/boost/range/iterator_range_core.hpp:38:
In file included from /usr/include/boost/range/functions.hpp:18:
/usr/include/boost/range/begin.hpp:47:17: error: member reference type 'std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int> *const' is a pointer; did you mean
to use '->'?
return c.begin();
~^
->
/usr/include/boost/range/begin.hpp:111:12: note: in instantiation of function template specialization 'boost::range_detail::range_begin<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, int> *const>' requested here
return range_begin( r );
^
/usr/include/boost/range/begin.hpp:127:46: note: in instantiation of function template specialization 'boost::range_adl_barrier::begin<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, int> *>' requested here
return boost::range_adl_barrier::begin( r );
^
/usr/include/boost/geometry/index/rtree.hpp:1417:30: note: in instantiation of function template specialization 'boost::range_adl_barrier::const_begin<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, int> *>' requested here
for ( It it = boost::const_begin(rng); it != boost::const_end(rng) ; ++it )
^
/usr/include/boost/geometry/index/rtree.hpp:624:15: note: in instantiation of function template specialization 'boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, unsigned int>, boost::geometry::index::quadratic<16, 4>,
boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >
>::insert_dispatch<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int> *>' requested here
this->insert_dispatch(conv_or_rng, is_conv_t());
^
note: in instantiation of function template specialization 'boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, unsigned int>, boost::geometry::index::quadratic<16, 4>,
boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >
>::insert<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int> *>' requested here
In file included from input_line_19:1:
In file included from /usr/include/boost/geometry.hpp:17:
In file included from /usr/include/boost/geometry/geometry.hpp:43:
In file included from /usr/include/boost/geometry/core/radian_access.hpp:28:
In file included from /usr/include/boost/geometry/util/math.hpp:28:
In file included from /usr/include/boost/math/constants/constants.hpp:18:
In file included from /usr/include/boost/lexical_cast.hpp:30:
In file included from /usr/include/boost/range/iterator_range_core.hpp:38:
In file included from /usr/include/boost/range/functions.hpp:18:
/usr/include/boost/range/begin.hpp:47:18: error: no member named 'begin' in 'std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int>'
return c.begin();
~ ^
In file included from input_line_19:1:
In file included from /usr/include/boost/geometry.hpp:17:
In file included from /usr/include/boost/geometry/geometry.hpp:43:
In file included from /usr/include/boost/geometry/core/radian_access.hpp:28:
In file included from /usr/include/boost/geometry/util/math.hpp:28:
In file included from /usr/include/boost/math/constants/constants.hpp:18:
In file included from /usr/include/boost/lexical_cast.hpp:30:
In file included from /usr/include/boost/range/iterator_range_core.hpp:38:
In file included from /usr/include/boost/range/functions.hpp:19:
/usr/include/boost/range/end.hpp:48:21: error: member reference type 'std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int> *const' is a pointer; did you mean
to use '->'?
return c.end();
~^
->
/usr/include/boost/range/end.hpp:105:12: note: in instantiation of function template specialization 'boost::range_detail::range_end<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, int> *const>' requested here
return range_end( r );
^
/usr/include/boost/range/end.hpp:121:46: note: in instantiation of function template specialization 'boost::range_adl_barrier::end<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, int> *>' requested here
return boost::range_adl_barrier::end( r );
^
/usr/include/boost/geometry/index/rtree.hpp:1417:61: note: in instantiation of function template specialization 'boost::range_adl_barrier::const_end<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, int> *>' requested here
for ( It it = boost::const_begin(rng); it != boost::const_end(rng) ; ++it )
^
/usr/include/boost/geometry/index/rtree.hpp:624:15: note: in instantiation of function template specialization 'boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, unsigned int>, boost::geometry::index::quadratic<16, 4>,
boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >
>::insert_dispatch<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int> *>' requested here
this->insert_dispatch(conv_or_rng, is_conv_t());
^
note: in instantiation of function template specialization 'boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, unsigned int>, boost::geometry::index::quadratic<16, 4>,
boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >
>::insert<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int> *>' requested here
In file included from input_line_19:1:
In file included from /usr/include/boost/geometry.hpp:17:
In file included from /usr/include/boost/geometry/geometry.hpp:43:
In file included from /usr/include/boost/geometry/core/radian_access.hpp:28:
In file included from /usr/include/boost/geometry/util/math.hpp:28:
In file included from /usr/include/boost/math/constants/constants.hpp:18:
In file included from /usr/include/boost/lexical_cast.hpp:30:
In file included from /usr/include/boost/range/iterator_range_core.hpp:38:
In file included from /usr/include/boost/range/functions.hpp:19:
/usr/include/boost/range/end.hpp:48:22: error: no member named 'end' in 'std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int>'
return c.end();
~ ^
Traceback (most recent call last):
File "try_cppyy_rtree.py", line 58, in <module>
rtree.insert(std.make_pair(b, i))
TypeError: Template method resolution failed:
void boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert(const boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::value_type& value) =>
TypeError: unbound method rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert must be called with a rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > > instance as first argument
void boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert(const std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int>& conv_or_rng) =>
TypeError: unbound method rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert must be called with a rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > > instance as first argument
void boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert(std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int>*const& conv_or_rng) =>
TypeError: unbound method rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert must be called with a rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > > instance as first argument
void boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert(const std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int>& conv_or_rng) =>
TypeError: unbound method rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert must be called with a rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > > instance as first argument
关于如何让它工作的任何见解？是否建议将 cppyy 用于我正在尝试的操作？我最初选择 cppyy 是因为我看到使用其他方法的示例似乎需要目标文件，但 boost rtree 是一个仅包含头文件的库。
使用 cppyy 1.8.5 有什么理由吗？脚本的问题与 cppyy 版本无关，但我只验证了它可以在 2.0.0（基于较新版本的 Clang）上正确运行。
这一行有问题：
rtree = bgi.rtree[value, bgi.quadratic(16)]
使得rtree仍然只是一个类型对象。将语法与您之前（正确）音译的前面的 typedef 进行比较。要获得 bgi::rtree 的实际实例，您需要实例化类型：
rtree = bgi.rtree[value, bgi.quadratic(16)]()
注意额外的 ()。
我检查过 b 被复制了，所以循环创建框应该没问题。否则，使用 Python，因为 b 将被垃圾收集（与原始示例中的 C++ 相同，实际上，因为它们是堆栈对象），它的生命周期应该被管理（例如通过使用 smart指针）。
以下代码有效：
import cppyy
cppyy.set_debug()
import cppyy.ll
cppyy.ll.set_signals_as_exception(True)
cppyy.add_include_path('/usr/include')
cppyy.include('boost/geometry.hpp')
cppyy.include('boost/geometry/geometries/point.hpp')
cppyy.include('boost/geometry/geometries/box.hpp')
cppyy.include('boost/geometry/index/rtree.hpp')
cppyy.include('vector')
cppyy.include('iostream')
cppyy.include('boost/foreach.hpp')
cpp = cppyy.gbl
std = cpp.std
bg = cpp.boost.geometry
bgi = cpp.boost.geometry.index
point = bg.model.point[float, 2, bg.cs.cartesian]
box = bg.model.box[point]
value = std.pair[box, 'unsigned']
rtree = bgi.rtree[value, bgi.quadratic(16)]
for i in range(10):
b = box(point(i + 0.0, i + 0.0), point(i + 0.5, i + 0.5))
print(bg.wkt[box](b))
with cppyy.ll.signals_as_exception():
rtree.insert(std.make_pair(b, i))
# find values intersecting some area defined by a box
query_box = box(point(0,0), point(5,5))
result_s = std.vector[value]()
rtree.query(bgi.intersects(query_box), std.back_inserter(result_s))
# find 5 nearest values to a point
result_n = std.vector[value]()
rtree.query(bgi.nearest(point(0,0), 5),
std.back_inserter(result_n))
# display results
print('spatial query box:')
print(bg.wkt[box](query_box))
print('spatial query result')
for v in result_s:
print(str(bg.wkt[box](v[0])) + " - " + str(v[1]))
print('knn query point:')
print(bg.wkt[point](point(0,0)))
print('knn query result')
for v in result_n:
print(str(bg.wkt[box](v[0])) + " - " + str(v[1]))
我正在尝试调整此 boost rtree example 以便 python 调用 c++ 库。这是我第一次尝试从 python 调用 c++。我在 ubuntu 16.04.7 LTS 上使用 cppyy 1.8.5（python 版本 3.6.7）和 boost rtree header-only 库（boost 版本 1.58）。这是我到目前为止的代码。
import cppyy
cppyy.set_debug()
import cppyy.ll
cppyy.ll.set_signals_as_exception(True)
cppyy.add_include_path('/usr/include')
cppyy.include('boost/geometry.hpp')
cppyy.include('boost/geometry/geometries/point.hpp')
cppyy.include('boost/geometry/geometries/box.hpp')
cppyy.include('boost/geometry/index/rtree.hpp')
cppyy.include('vector')
cppyy.include('iostream')
cppyy.include('boost/foreach.hpp')
cpp = cppyy.gbl
std = cpp.std
bg = cpp.boost.geometry
bgi = cpp.boost.geometry.index
point = bg.model.point[float, 2, bg.cs.cartesian]
box = bg.model.box[point]
value = std.pair[box, 'unsigned']
rtree = bgi.rtree[value, bgi.quadratic(16)]
for i in range(10):
b = box(point(i + 0.0, i + 0.0), point(i + 0.5, i + 0.5))
print(bg.wkt[box](b))
with cppyy.ll.signals_as_exception():
rtree.insert(std.make_pair(b, i))
在 for 循环中，框已创建，但 rtree.insert() 调用产生错误。
$ python try_cppyy_rtree.py
TClass::GetClass: Header Parsing - The representation of __cppyy_internal was not found in the type system. A lookup in the interpreter is about to be tried: this can cause parsing. This can be avoided selecting __cppyy_internal in the linkdef/selection file.
...<trimmed>...
TClass::GetClass: Header Parsing - The representation of boost::geometry::wkt_manipulator<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> > > was not found in the type system. A lookup in the interpreter is about to be tried: this can cause parsing. This can be avoided selecting boost::geometry::wkt_manipulator<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> > > in the linkdef/selection file.
POLYGON((0 0,0 0.5,0.5 0.5,0.5 0,0 0))
TClass::GetClass: Header Parsing - The representation of std::make_pair was not found in the type system. A lookup in the interpreter is about to be tried: this can cause parsing. This can be avoided selecting std::make_pair in the linkdef/selection file.
TClass::GetClass: Header Parsing - The representation of std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int> was not found in the type system. A lookup in the interpreter is about to be tried: this can cause parsing. This can be avoided selecting std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int> in the linkdef/selection file.
TClass::GetClass: Header Parsing - The representation of std::__pair_base<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int> was not found in the type system. A lookup in the interpreter is about to be tried: this can cause parsing. This can be avoided selecting std::__pair_base<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int> in the linkdef/selection file.
In file included from input_line_19:1:
In file included from /usr/include/boost/geometry.hpp:17:
In file included from /usr/include/boost/geometry/geometry.hpp:43:
In file included from /usr/include/boost/geometry/core/radian_access.hpp:28:
In file included from /usr/include/boost/geometry/util/math.hpp:28:
In file included from /usr/include/boost/math/constants/constants.hpp:18:
In file included from /usr/include/boost/lexical_cast.hpp:30:
In file included from /usr/include/boost/range/iterator_range_core.hpp:38:
In file included from /usr/include/boost/range/functions.hpp:18:
/usr/include/boost/range/begin.hpp:47:17: error: member reference type 'std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int> *const' is a pointer; did you mean
to use '->'?
return c.begin();
~^
->
/usr/include/boost/range/begin.hpp:111:12: note: in instantiation of function template specialization 'boost::range_detail::range_begin<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, int> *const>' requested here
return range_begin( r );
^
/usr/include/boost/range/begin.hpp:127:46: note: in instantiation of function template specialization 'boost::range_adl_barrier::begin<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, int> *>' requested here
return boost::range_adl_barrier::begin( r );
^
/usr/include/boost/geometry/index/rtree.hpp:1417:30: note: in instantiation of function template specialization 'boost::range_adl_barrier::const_begin<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, int> *>' requested here
for ( It it = boost::const_begin(rng); it != boost::const_end(rng) ; ++it )
^
/usr/include/boost/geometry/index/rtree.hpp:624:15: note: in instantiation of function template specialization 'boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, unsigned int>, boost::geometry::index::quadratic<16, 4>,
boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >
>::insert_dispatch<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int> *>' requested here
this->insert_dispatch(conv_or_rng, is_conv_t());
^
note: in instantiation of function template specialization 'boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, unsigned int>, boost::geometry::index::quadratic<16, 4>,
boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >
>::insert<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int> *>' requested here
In file included from input_line_19:1:
In file included from /usr/include/boost/geometry.hpp:17:
In file included from /usr/include/boost/geometry/geometry.hpp:43:
In file included from /usr/include/boost/geometry/core/radian_access.hpp:28:
In file included from /usr/include/boost/geometry/util/math.hpp:28:
In file included from /usr/include/boost/math/constants/constants.hpp:18:
In file included from /usr/include/boost/lexical_cast.hpp:30:
In file included from /usr/include/boost/range/iterator_range_core.hpp:38:
In file included from /usr/include/boost/range/functions.hpp:18:
/usr/include/boost/range/begin.hpp:47:18: error: no member named 'begin' in 'std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int>'
return c.begin();
~ ^
In file included from input_line_19:1:
In file included from /usr/include/boost/geometry.hpp:17:
In file included from /usr/include/boost/geometry/geometry.hpp:43:
In file included from /usr/include/boost/geometry/core/radian_access.hpp:28:
In file included from /usr/include/boost/geometry/util/math.hpp:28:
In file included from /usr/include/boost/math/constants/constants.hpp:18:
In file included from /usr/include/boost/lexical_cast.hpp:30:
In file included from /usr/include/boost/range/iterator_range_core.hpp:38:
In file included from /usr/include/boost/range/functions.hpp:19:
/usr/include/boost/range/end.hpp:48:21: error: member reference type 'std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int> *const' is a pointer; did you mean
to use '->'?
return c.end();
~^
->
/usr/include/boost/range/end.hpp:105:12: note: in instantiation of function template specialization 'boost::range_detail::range_end<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, int> *const>' requested here
return range_end( r );
^
/usr/include/boost/range/end.hpp:121:46: note: in instantiation of function template specialization 'boost::range_adl_barrier::end<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, int> *>' requested here
return boost::range_adl_barrier::end( r );
^
/usr/include/boost/geometry/index/rtree.hpp:1417:61: note: in instantiation of function template specialization 'boost::range_adl_barrier::const_end<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, int> *>' requested here
for ( It it = boost::const_begin(rng); it != boost::const_end(rng) ; ++it )
^
/usr/include/boost/geometry/index/rtree.hpp:624:15: note: in instantiation of function template specialization 'boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, unsigned int>, boost::geometry::index::quadratic<16, 4>,
boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >
>::insert_dispatch<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int> *>' requested here
this->insert_dispatch(conv_or_rng, is_conv_t());
^
note: in instantiation of function template specialization 'boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2,
boost::geometry::cs::cartesian> >, unsigned int>, boost::geometry::index::quadratic<16, 4>,
boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >,
std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, unsigned int> >
>::insert<std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int> *>' requested here
In file included from input_line_19:1:
In file included from /usr/include/boost/geometry.hpp:17:
In file included from /usr/include/boost/geometry/geometry.hpp:43:
In file included from /usr/include/boost/geometry/core/radian_access.hpp:28:
In file included from /usr/include/boost/geometry/util/math.hpp:28:
In file included from /usr/include/boost/math/constants/constants.hpp:18:
In file included from /usr/include/boost/lexical_cast.hpp:30:
In file included from /usr/include/boost/range/iterator_range_core.hpp:38:
In file included from /usr/include/boost/range/functions.hpp:19:
/usr/include/boost/range/end.hpp:48:22: error: no member named 'end' in 'std::pair<boost::geometry::model::box<boost::geometry::model::point<float, 2, boost::geometry::cs::cartesian> >, int>'
return c.end();
~ ^
Traceback (most recent call last):
File "try_cppyy_rtree.py", line 58, in <module>
rtree.insert(std.make_pair(b, i))
TypeError: Template method resolution failed:
void boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert(const boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::value_type& value) =>
TypeError: unbound method rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert must be called with a rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > > instance as first argument
void boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert(const std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int>& conv_or_rng) =>
TypeError: unbound method rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert must be called with a rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > > instance as first argument
void boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert(std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int>*const& conv_or_rng) =>
TypeError: unbound method rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert must be called with a rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > > instance as first argument
void boost::geometry::index::rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert(const std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,int>& conv_or_rng) =>
TypeError: unbound method rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > >::insert must be called with a rtree<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int>,boost::geometry::index::quadratic<16,4>,boost::geometry::index::indexable<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,boost::geometry::index::equal_to<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> >,std::allocator<std::pair<boost::geometry::model::box<boost::geometry::model::point<float,2,boost::geometry::cs::cartesian> >,unsigned int> > > instance as first argument
关于如何让它工作的任何见解？是否建议将 cppyy 用于我正在尝试的操作？我最初选择 cppyy 是因为我看到使用其他方法的示例似乎需要目标文件，但 boost rtree 是一个仅包含头文件的库。
使用 cppyy 1.8.5 有什么理由吗？脚本的问题与 cppyy 版本无关，但我只验证了它可以在 2.0.0（基于较新版本的 Clang）上正确运行。
这一行有问题：
rtree = bgi.rtree[value, bgi.quadratic(16)]
使得rtree仍然只是一个类型对象。将语法与您之前（正确）音译的前面的 typedef 进行比较。要获得 bgi::rtree 的实际实例，您需要实例化类型：
rtree = bgi.rtree[value, bgi.quadratic(16)]()
注意额外的 ()。
我检查过 b 被复制了，所以循环创建框应该没问题。否则，使用 Python，因为 b 将被垃圾收集（与原始示例中的 C++ 相同，实际上，因为它们是堆栈对象），它的生命周期应该被管理（例如通过使用 smart指针）。
以下代码有效：
import cppyy
cppyy.set_debug()
import cppyy.ll
cppyy.ll.set_signals_as_exception(True)
cppyy.add_include_path('/usr/include')
cppyy.include('boost/geometry.hpp')
cppyy.include('boost/geometry/geometries/point.hpp')
cppyy.include('boost/geometry/geometries/box.hpp')
cppyy.include('boost/geometry/index/rtree.hpp')
cppyy.include('vector')
cppyy.include('iostream')
cppyy.include('boost/foreach.hpp')
cpp = cppyy.gbl
std = cpp.std
bg = cpp.boost.geometry
bgi = cpp.boost.geometry.index
point = bg.model.point[float, 2, bg.cs.cartesian]
box = bg.model.box[point]
value = std.pair[box, 'unsigned']
rtree = bgi.rtree[value, bgi.quadratic(16)]
for i in range(10):
b = box(point(i + 0.0, i + 0.0), point(i + 0.5, i + 0.5))
print(bg.wkt[box](b))
with cppyy.ll.signals_as_exception():
rtree.insert(std.make_pair(b, i))
# find values intersecting some area defined by a box
query_box = box(point(0,0), point(5,5))
result_s = std.vector[value]()
rtree.query(bgi.intersects(query_box), std.back_inserter(result_s))
# find 5 nearest values to a point
result_n = std.vector[value]()
rtree.query(bgi.nearest(point(0,0), 5),
std.back_inserter(result_n))
# display results
print('spatial query box:')
print(bg.wkt[box](query_box))
print('spatial query result')
for v in result_s:
print(str(bg.wkt[box](v[0])) + " - " + str(v[1]))
print('knn query point:')
print(bg.wkt[point](point(0,0)))
print('knn query result')
for v in result_n:
print(str(bg.wkt[box](v[0])) + " - " + str(v[1]))