[no subject]

I've been massaging the Eigen code this afternoon trying to help XLC
get through some of the fancier template/template arguments and friend
template arguments called by Eigen.  As far as I can tell, everything
is 'doable', but it will make the Eigen code base a fair amount uglier
to include this sort of compatibility.

I've generated a patch file here (good for a month):
http://pastebin.com/m17b12fcb which show a portion of the edits which
will be required for XLC compatibility.

The most common edits are regarding template template arguments:
-template<typename Derived> struct AnyMatrixBase
+template<template <typename, typename> class Derived> struct AnyMatrixBase

The XLC compiler does not accept template template arguments if they
are not parametrized (i.e., you cannot put in "typename Derived" if
Derived is actually a template class).

I don't know how deep the rabbit hole goes as I've just spent a few
hours looking at this.  I do know that adding XLC portability would
broadly affect the Eigen source tree.  Since this is my first real
interaction with an open source project, I'm not sure of the etiquette
on how to proceed here.  Do I generate a branch that compiles and runs
on BGP and report that back?  Should I be working against development
or stable?

I am interested in seeing Eigen ported to IBM BlueGene and other IBM
high-performance platforms.  I'm happy to help support this with my
own coding efforts and getting support from my University.  As of now,
this isn't an official project for me so it is getting worked on in my
spare time.

Thanks,
Aron