id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
6072	Bad iterator difference for m.begin1() - m.end1() in ublas	Robin Palotai <palotai.robin@…>	Gunter	"In functional.hpp at a couple of places, for example:

         static
         BOOST_UBLAS_INLINE
         difference_type distance_i (difference_type k, size_type /* size_i */, size_type size_j) {
             return size_j != 0 ? k / size_j : 0;
         }

k [ / | % ] size_[ i | j ] is used, where k is difference_type (signed), size_i|j is size_type (unsigned). This results in promoting k to unsigned, and can yield very strange results when k is negative.

For example, m being a size 2x2 ublas::matrix, 
m.begin1() - m.end1() 
yields 2147483646 instead of -2. 

Putting a static_cast<difference_type>(size_i|j) in functional.hpp
seems to solve the problem."	Bugs	new	To Be Determined	uBLAS	Boost 1.47.0	Problem		iterator, distance