hello, I am not sure if this is intended, but it appears that there is redundant copy in
matrix.hpp

139         // Resizing
140         BOOST_UBLAS_INLINE
141         void resize (size_type size1, size_type size2, bool preserve = true) {
142             if (preserve) {
143                 self_type temporary (size1, size2);
144                 detail::matrix_resize_preserve<layout_type> (*this, temporary);
145             }
146             else {
147                 data ().resize (layout_type::storage_size (size1, size2));
148                 size1_ = size1;
149                 size2_ = size2;
150             }
151         }

should line 147 read

data ().resize (layout_type::storage_size (size1, size2), false);

thank you