[R] Status of Rmpi--Good with tweaks

[Ross Boylan]

On Tue, 2004-03-23 at 17:35, Luke Tierney wrote:
> The serialize package should no longer be needed since the
> functionality is now in R itself.  I haven't run snow with a new
> version of Rmpi newer than 0.4-4; with that version things worked on
> my systems the last time I tried.  We need to revize the paper you
> cite; when we get to that we'll hopefully have a chance to give a
> newer version of Rmpi a go.
> 
> Best,
> 
> luke

I got 0.4-6 to work, with one tweak to eliminate the loading of
serialize and one fix of my own setup.

I changed the .First.Lib code in Rmpi to be
    if (!exists("serialize") && !require(serialize))
	stop("serialize package cannot be loaded. Exit")	

!exists("serialize") && is new.  This is effort to check if the
serialize function exists (R 1.8) and skip loading the library in that
case.  Since there are various ways this might be fooled, perhaps an
explicit check of the R version would be better.

I'm also not sure if the R packaging mechanism makes this easy, or
autogenerates it.  This is a bit of a tricky situation, since serialize
is required for some versions of R but should not be used for the most
recent.

I suspect that without this the cluster would not come up because Rmpi
would not load properly.  I have not tested that.

The other problem was of my own making.  I had Rmpi in a local
directory, loaded with lib.loc.  The children don't know about this, and
automatically try to load Rmpi.  I solved this by setting .Renviron with
the proper R_LIBS path.  (By the way, I wanted to say
R_LIBS=~/lib:${R_LIBS}, but that syntax doesn't work.  This is
consistent with the documentation, just awkward.)

I also ran into a couple of snow things, really documentation issues,
that I'll put in a separate message.