id summary reporter owner description type status milestone component version severity resolution keywords cc 12268 Boost Polygon: Overflow issue with euclidean_distance() when using large (32-bit) coordinates. Pallav Gupta Lucanus Simonson "Hi, When using large (32-bit) ints for coordinates, there seems to be a problem in getting the correct result with boost::polygon::euclidean_distance(). The sample program demonstrates the issue (compiled with GCC 4.7.3 + Boost 1.61.0). {{{ #include #include #include #include namespace gtl = boost::polygon; using namespace boost::polygon::operators; typedef gtl::rectangle_data LayoutRectangle; int main(int argc, char** argv) { LayoutRectangle t(16740130,29759232,16740350,29760652); LayoutRectangle n(16808130,29980632,16808350,29982052); std::cout << gtl::euclidean_distance(t, n) << std::endl; std::cout << gtl::euclidean_distance(t, n, gtl::HORIZONTAL) << "" "" << gtl::euclidean_distance(t, n, gtl::VERTICAL) << std::endl; std::cout << gtl::square_euclidean_distance(t, n) << std::endl; std::cout << std::sqrt(gtl::square_euclidean_distance(t, n)) << std::endl; std::cout << (int) std::sqrt(gtl::square_euclidean_distance(t, n)) << std::endl; return 0; } }}} The output of this program is: 38022.6 67780 219980 52985328800 230185 230185 230185 is the correct answer, but euclidean_distance() gives 38022.6. I traced the program above in GDB, and the culprit seems to be 'return (xdist * xdist) + (ydist * ydist)' in the library code shown below. xdist/ydist have correct values but taking the square root is most likely causing overflow. rectangle_concept.hpp: {{{ square_euclidean_distance(const rectangle_type& lvalue, const rectangle_type_2& rvalue) { typename coordinate_traits::type>::coordinate_difference xdist, ydist; xdist = euclidean_distance(lvalue, rvalue, HORIZONTAL); ydist = euclidean_distance(lvalue, rvalue, VERTICAL); return (xdist * xdist) + (ydist * ydist); } }}} I notice coordinate_difference is defined as 'long long' which is 8 bytes (sizeof(long long)) on my machine. So not sure why this is happening. I also posted this as a question on stackoverflow: http://stackoverflow.com/questions/37804930/boost-polygon-issue-with-euclidean-distance For now, I can use std::sqrt(gtl::square_euclidean_distance())' as a workaround. Thanks. " Bugs new To Be Determined polygon Boost 1.61.0 Problem euclidean_distance