Re: Adding Trilinos to dealii package

[zimoun <zimon.toutoune@gmail.com>]

Hi,

> PETSc and Trilinos (and many other libraries available in Guix) can be
> compiled with several different options.
> What is the standard way to deal with this in Guix?

AFAIK, there is no concrete standard way.  Only what explained Arun. ;-) 

> The potential problem with PETSc and Trilinos when it comes to dealii is
> that some of the optional modules they can be compiled with are the
> same, which causes trouble when dealii is configured with both of
> them [2].
> (From what I can tell, the module in question is not configured in the
> Guix package for PETSc, so this point may be moot.)

What I miss is: Trilinos is somehow a replacement of PETSc.  You would
like Deal.II compiled with both Trilinos *and* PETSc support, right?

> I'm wondering what the best way would be to add Trilinos to the dealii
> packages (assuming I manage to package Trilinos as well).

FWIW, I would start by package Trilinos. ;-)

> - Some other possibility I have not thought of.

IIUC, your question is how Guix deals with “package parameters“, right?
And the answer is: it is complicated. ;-)

First, I do not know if it is worth to have many variants in Guix
proper.  There is 2 things to consider: a) how complicated the recipe of
the variant is?  and b) how much resource (CPU, RAM, etc.) does the
variant require to be built?  Somehow, if the recipe is simple enough,
by simply apply package transformation (say), and if it can be built on
a powerless laptop (say), then the variant does not worth, IMHO.  Else,
it is an open discussion. ;-)

Second, I would like to mention the guix-science@gnu.org mailing list
where this kind of questions are sometimes discussed.  And
hpc.guix.info/about lists scientific channels where the workload could
be shared.

Hope that helps,
simon