Hi, I need to handle extremely large sparse matrices, of approximately half a million square elements (with, typically, on the order of 5 million non-zero entries). The following, however, fails on a machine where std::size_t is 4 bytes long: #include <boost/numeric/ublas/matrix_sparse.hpp> int main () { using namespace boost::numeric::ublas; sparse_matrix<double> m(400000, 400000); } It fails with Assertion failed in file boost/numeric/ublas/functional.hpp at line 1345: (size1 * size2) / size1 == size2 Obviously, while both size1 and size2 fit in a 4-byte integer, the product does not, the calculation overflows, and this check fails. Can this problem be circumvented without modifying boost? Kasper