Hi. i'm compiling the attached file with MVC++ which ouputs a greap number of errors regarding a "boost::numeric::ublas::project" function. I couldn't quite work out what the problem was, but it turns out that when i include "vector_proxy.hpp" in my code it all compiles fine (as per the commented line). It would then seem that it is the call to lu_factorize that creates this error. Maybe a missing include in lu.hpp?