Hi, I have recently downloaded Boost… I tried the example in the “getting started” page (Lambda)… it worked which means that the installation is fine… The main purpose of installing Boost is that I want to generate graphs using R-MAT in which I found an example at: http://www.boost.org/doc/libs/1_50_0/libs/graph_parallel/doc/html/scalable_r... I copied the example and pasted it in the place of the (Lambda) example to make sure that the project is opened correctly (I’m using visual stdio 2012), however, It did not compile successfully, I received the following error: fatal error C1189: #error : "Parallel BGL files should not be included unless <boost/graph/use_mpi.hpp> has been included" I tried to include <boost/graph/use_mpi.hpp> but with no luck, I received the following error: fatal error C1083: Cannot open include file: 'mpi.h': No such file or directory What should I do? Please help me… Best regards, Nouf