These ebuilds come from http://wiki.gentoo.org/wiki/Project:Science.
If you have some problems, go to the official site first.
mpibash : Parallel scripting right from the Bourne-Again Shell (Bash) ( http://www.ccs3.lanl.gov/~pakin/software/mpibash-4.3.html )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a science
For Paludis use this rsync : rsync://gentoo.zugaina.org/science-portage
If you have a problem : ycarus(-at-)zugaina.org