Hi, I am relatively new to Boost and I find it an excellent C++ library. During my experiments with the library, I tried the sparse matrix classes offered by uBLAS. Unfortunately, I think that reverse_iterators of these classes do not work correctly. Below is my sample code, which demonstrates some problems; the problems are the same with all three sparse matrix classes. I tried it with gcc 3.4.1 on Linux. Any comments would be appreciated. Thanks in advance, Nikos Platis PS. I post here instead of the uBLAS Yahoo Group because I am still waiting for membership approval... ---------------------------------------------------- #include <iostream> #include <boost/numeric/ublas/matrix_sparse.hpp> #include <boost/numeric/ublas/io.hpp> namespace ublas = boost::numeric::ublas; //typedef ublas::sparse_matrix<double> spmd; //typedef ublas::compressed_matrix<double> spmd; typedef ublas::coordinate_matrix<double> spmd; int main() { // Construct a sample sparse matrix spmd M(5, 5); M(0,0) = 11; M(0,2) = 13; M(1,0) = 21; M(1,1) = 22; M(2,2) = 33; M(2,4) = 35; M(3,3) = 44; M(4,0) = 52; M(4,4) = 55; /* OK */ for (spmd::const_iterator1 it1 = M.begin1(); it1 != M.end1(); ++it1) { for (spmd::const_iterator2 it2 = it1.begin(); it2 != it1.end(); ++it2) { std::cout << it2.index1() << " " << it2.index2() << ": " << *it2 << std::endl; } } std::cout << std::endl << std::endl; /* The following does not compile, error about the const reverse iterators for (spmd::const_reverse_iterator1 it1 = M.rbegin1(); it1 != M.rend1(); ++it1) { for (spmd::const_reverse_iterator2 it2 = it1.rbegin(); it2 != it1.rend(); ++it2) { std::cout << it2.index1() << " " << it2.index2() << ": " << *it2 << std::endl; } } std::cout << std::endl << std::endl; */ /* The following compiles but throws bad_index exception */ for (spmd::reverse_iterator1 it1 = M.rbegin1(); it1 != M.rend1(); ++it1) { for (spmd::reverse_iterator2 it2 = it1.rbegin(); it2 != it1.rend(); ++it2) { std::cout << it2.index1() << " " << it2.index2() << ": " << *it2 << std::endl; } } std::cout << std::endl << std::endl; } ---------------------------------------------------- -- ----------------------------------------------------------------------- Nikos Platis e-mail: nplatis@di.uoa.gr Department of Informatics tel: +30 210-727-5106 University of Athens fax: +30 210-727-5114 "The empires of the future are the empires of the mind." - W. Churchill -----------------------------------------------------------------------