Hello, in the package "snow" there will be used mpi.send in the function sendData.MPInode. Why you do not use the nonblocking function mpi.isend? This will be much faster. The same is for recvData. But in rmpi the function "mpi.irecv.Robj" is still missing (see Mail "Rmpi, mpi.irecv.Robj") (I have some problems with the mailinglist. I all the time got back the message: "Message rejected by filter rule match") Best Markus Schmidberger -- Dipl.-Tech. Math. Markus Schmidberger Ludwig-Maximilians-Universit?t M?nchen IBE - Institut f?r medizinische Informationsverarbeitung, Biometrie und Epidemiologie Marchioninistr. 15, D-81377 Muenchen URL: http://ibe.web.med.uni-muenchen.de Mail: Markus.Schmidberger [at] ibe.med.uni-muenchen.de