Hi Seungbum,

do I need to run "mpd" every time before I run "mpiexec"?

No. You shouldn't need to run mpd at all.

From the FAQ: "The mpd process manager has many problems, as well as an annoying mpdboot step that is fragile and difficult to use correctly. The mpd process manager is deprecated at this point ..."

Perhaps when you typed "mpiexec", you were not really running the mpiexec binary that you had just built, but rather some other (really old) version that was already lying around on your system? I'd suggest: running "which mpiexec" and "mpiexec --version" checking your $PATH specifying an absolute pathname to the new mpiexec binary instead of just "mpiexec" Hope this helps, Nicolás