Hi all! In boost::numeric::ublas, there exist different vector variants (unbounded and bounded). All of them can be resized dynamically (up to a maximum size defined at compile time in the case of the bounded vector). Therefore the vector class (or the underlying storage array) have a size member which indicates the current size of the vector. However, it would be extremely useful to have a vector of fixed size, i.e., one which can't be resized dynamically, but has its size statically defined at compile time. Such a vector does not require a size member and only consumes N*sizeof(T) bytes of storage, where N is the (static) vector size and T the value type. Many libraries dealing with geometric data (OpenGL and OpenInventor being prominent examples) store their data in compact arrays in their native data types, e.g., the values (x0,y0,z0,x1,y1,z1,x2,y2,z2) stored in consecutive memory locations define three points in 3D space. By means of a fixed size vector, the entire boost::numeric::ublas functionality could be applied to such arrays by a simple reinterpret_cast on each element. This is not possible with the bounded or unbounded vectors since the vector must be constructed before with its size member properly initialized, and the actual vector data must therefore be copied explicitly before use. I tried to create a fixed_array class to implement this proposal (see attachment), it can be used, e.g., to create the equivalent of the OpenInventor "SbVec3f" data type as follows: typedef boost::numeric::ublas::vector<float,fixed_array<float,3> > vec3d_t; It is probably not the cleanest solution, and I skipped the serialization stuff altogether, but it demonstrates an approach how this can be done. What do you think about adding such an extension to improve boost's interoperability with other libraries? Thanks & kind regards, Markus -- Markus Grabner Institute for Computer Graphics and Vision Graz University of Technology, Inffeldgasse 16a/II, 8010 Graz, Austria WWW: http://www.icg.tugraz.at/Members/grabner