Hello, I've got a problem compiling the next example: #include <iostream> #include <boost/numeric/ublas/matrix_sparse.hpp> #include <boost/numeric/ublas/storage.hpp> #include <boost/numeric/ublas/io.hpp> using namespace boost::numeric::ublas; int main(void) { sparse_matrix<unsigned> *m, *n, *r; m = new sparse_matrix<unsigned>(3,3); n = new sparse_matrix<unsigned>(3,3); r = new sparse_matrix<unsigned>(3,3); for (unsigned i = 0; i < 3; ++i) for (unsigned j = 0; j < 3; ++j) (*m)(i,j) = i+j; *n = *m; //no problems in assignment *r = *m + *n; //this gives problems!! std::cout << *r << std::endl; return 0; } This example compiles on a Pentium4 with gcc 3.2.3, but not on an Opteron with gcc 4.0.0. When the line with addition of the two matrices is commented out, the example compiles. I'm not sure if it's a 64-bit problem (P4 vs Opteron) or a gcc version problem. Anybody got any ideas? The errors I get are listed below: /usr/include/boost/numeric/ublas/matrix_sparse.hpp: In instantiation of ‘boost::numeric::ublas::type_traits<boost::numeric::ublas::sparse_matrix_element<boost::numeric::ublas::sparse_matrix<unsigned int, boost::numeric::ublas::row_major, boost::numeric::ublas::map_std<size_t, unsigned int, std::allocator<std::pair<const size_t, unsigned int> > > > > >’: /usr/include/boost/numeric/ublas/functional.hpp:183: instantiated from ‘boost::numeric::ublas::scalar_binary_assign_functor<boost::numeric::ublas::sparse_matrix_element<boost::numeric::ublas::sparse_matrix<unsigned int, boost::numeric::ublas::row_major, boost::numeric::ublas::map_std<size_t, unsigned int, std::allocator<std::pair<const size_t, unsigned int> > > > >, unsigned int>’ /usr/include/boost/numeric/ublas/functional.hpp:192: instantiated from ‘boost::numeric::ublas::scalar_assign<boost::numeric::ublas::sparse_matrix_element<boost::numeric::ublas::sparse_matrix<unsigned int, boost::numeric::ublas::row_major, boost::numeric::ublas::map_std<size_t, unsigned int, std::allocator<std::pair<const size_t, unsigned int> > > > >, unsigned int>’ /usr/include/boost/numeric/ublas/matrix_assign.hpp:1265: instantiated from ‘void boost::numeric::ublas::matrix_assign(F, M&, const boost::numeric::ublas::matrix_expression<E2>&) [with F = boost::numeric::ublas::scalar_assign<unsigned int&, unsigned int>, M = boost::numeric::ublas::sparse_matrix<unsigned int, boost::numeric::ublas::row_major, boost::numeric::ublas::map_std<size_t, unsigned int, std::allocator<std::pair<const size_t, unsigned int> > > >, E = boost::numeric::ublas::matrix_binary<boost::numeric::ublas::sparse_matrix<unsigned int, boost::numeric::ublas::row_major, boost::numeric::ublas::map_std<size_t, unsigned int, std::allocator<std::pair<const size_t, unsigned int> > > >, boost::numeric::ublas::sparse_matrix<unsigned int, boost::numeric::ublas::row_major, boost::numeric::ublas::map_std<size_t, unsigned int, std::allocator<std::pair<const size_t, unsigned int> > > >, boost::numeric::ublas::scalar_plus<unsigned int, unsigned int> >]’ /usr/include/boost/numeric/ublas/matrix_sparse.hpp:285: instantiated from ‘boost::numeric::ublas::sparse_matrix<T, F, A>::sparse_matrix(const boost::numeric::ublas::matrix_expression<E1>&, typename A::size_type) [with AE = boost::numeric::ublas::matrix_binary<boost::numeric::ublas::sparse_matrix<unsigned int, boost::numeric::ublas::row_major, boost::numeric::ublas::map_std<size_t, unsigned int, std::allocator<std::pair<const size_t, unsigned int> > > >, boost::numeric::ublas::sparse_matrix<unsigned int, boost::numeric::ublas::row_major, boost::numeric::ublas::map_std<size_t, unsigned int, std::allocator<std::pair<const size_t, unsigned int> > > >, boost::numeric::ublas::scalar_plus<unsigned int, unsigned int> >, T = unsigned int, F = boost::numeric::ublas::row_major, A = boost::numeric::ublas::map_std<size_t, unsigned int, std::allocator<std::pair<const size_t, unsigned int> > >]’ /usr/include/boost/numeric/ublas/matrix_sparse.hpp:390: instantiated from ‘boost::numeric::ublas::sparse_matrix<T, F, A>& boost::numeric::ublas::sparse_matrix<T, F, A>::operator=(const boost::numeric::ublas::matrix_expression<E1>&) [with AE = boost::numeric::ublas::matrix_binary<boost::numeric::ublas::sparse_matrix<unsigned int, boost::numeric::ublas::row_major, boost::numeric::ublas::map_std<size_t, unsigned int, std::allocator<std::pair<const size_t, unsigned int> > > >, boost::numeric::ublas::sparse_matrix<unsigned int, boost::numeric::ublas::row_major, boost::numeric::ublas::map_std<size_t, unsigned int, std::allocator<std::pair<const size_t, unsigned int> > > >, boost::numeric::ublas::scalar_plus<unsigned int, unsigned int> >, T = unsigned int, F = boost::numeric::ublas::row_major, A = boost::numeric::ublas::map_std<size_t, unsigned int, std::allocator<std::pair<const size_t, unsigned int> > >]’ comp_mat.cpp:27: instantiated from here /usr/include/boost/numeric/ublas/matrix_sparse.hpp:156: error: no type named ‘real_type’ in ‘struct boost::numeric::ublas::type_traits<unsigned int>’ /usr/include/boost/numeric/ublas/matrix_sparse.hpp:157: error: no type named ‘precision_type’ in ‘struct boost::numeric::ublas::type_traits<unsigned int>’ /usr/include/boost/numeric/ublas/matrix_sparse.hpp:159: error: ‘plus_complexity’ is not a member of ‘boost::numeric::ublas::type_traits<unsigned int>’ /usr/include/boost/numeric/ublas/matrix_sparse.hpp:160: error: ‘multiplies_complexity’ is not a member of ‘boost::numeric::ublas::type_traits<unsigned int>’ /usr/include/boost/numeric/ublas/matrix_sparse.hpp:164: error: no type named ‘real_type’ in ‘struct boost::numeric::ublas::type_traits<unsigned int>’ /usr/include/boost/numeric/ublas/matrix_sparse.hpp:169: error: no type named ‘real_type’ in ‘struct boost::numeric::ublas::type_traits<unsigned int>’ /usr/include/boost/numeric/ublas/matrix_sparse.hpp:180: error: no type named ‘real_type’ in ‘struct boost::numeric::ublas::type_traits<unsigned int>’ /usr/include/boost/numeric/ublas/matrix_sparse.hpp:191: error: no type named ‘real_type’ in ‘struct boost::numeric::ublas::type_traits<unsigned int>’ /usr/include/boost/numeric/ublas/matrix_sparse.hpp:196: error: no type named ‘real_type’ in ‘struct boost::numeric::ublas::type_traits<unsigned int>’ /usr/include/boost/numeric/ublas/matrix_sparse.hpp:201: error: no type named ‘real_type’ in ‘struct boost::numeric::ublas::type_traits<unsigned int>’ Thanks and best wishes, Menno Deij