id summary reporter owner description type status milestone component version severity resolution keywords cc 2692 No concepts supporting the idea of dense dougrm@… Gunter "data() returns a reference to a Storage. However, nowhere in the concepts is a statement saying that &m.data()[0] must to be the address of the first element of the linearly stored data in the Storage. The adjective ""dense"" is used all over, but nowhere is this term given any operational guarantees. Without such guarantees, all the interfaces in, say, the numerics::binding libraries are being built on sand. Related to this is that nothing requires unbounded_array::value_type to be T. The problem boils down to the ublas concepts documentation borrowing from the stl vector concepts which are general enough to support vector. The basic (and inadequate) change is the sprinkling around of the word dense and the phrase ""strict linear order"". Instead you need to explicitly says things like value_type is T and &v[i+j] == &v[i]+j (for reasonable i+j)." Feature Requests assigned To Be Determined uBLAS Boost 1.37.0 Optimization