[Users] Meeting Minutes

[Erik Schnetter]

On Mar 25, 2014, at 10:30 , Ian Hinder <ian.hinder at aei.mpg.de> wrote:

> On 25 Mar 2014, at 14:53, Frank Loeffler <knarf at cct.lsu.edu> wrote:
> 
>> On Mon, Mar 24, 2014 at 04:07:35PM -0700, Roland Haas wrote:
>>> According to the minutes from 2013-12-16 a decision was reached:
>> 
>> Thanks for digging this out. This is what I remembered.
>> 
>>> What is not in the notes is that Ian also desired a way to force it to
>>> download so that for cluster where no network connection (or git) is
>>> available at build time (or preparing for a flight) one can force
>>> download on ones laptop then use simfactory to sync the tarballs.
>> 
>> I think we mentioned at least in the call that such a possibility should
>> exist - an option to download all possibly required tarballs.
> 
> The obvious place to store the URL for the tarball is in the configuration.ccl file.  What is the recommended procedure for reading entries from this file outside of the build system?  It would have been nice to find that the Perl files in lib/sbin were Perl modules which could be used outside the build system, but I was disappointed to find this was not the case.  The file is parsed by lib/sbin/ConfigurationParser.pl.

I think we want to move away from building external libraries as part of the Cactus build; instead, we want to build them ahead of time, e.g. via Simfactory. This has several advantages, such as e.g. that a "make clean" doesn't require rebuilding the libraries, and that several Cactus configurations can use the same external libraries, and that one can even have one power user build the libraries on a system while all others simply use them.

One additional advantage is that building external libraries from within Cactus is actually quite difficult, since the Cactus compiler options are often "strange" and need to be "cleaned" before one can use them. The respective shell code is arcane, and often breaks between different system. Building external libraries on their own, independent of Cactus, is much simpler.

I know this because I implemented this in Simfactory3, and I definitively think this is the way to go. The current build recipes use Clang (not gcc, and not the system's "standard" compiler) for building. I did this because I was interested in C++11, and most system compilers (Intel, PGI, older versions of GCC, current Nvidia) don't support this. However, in the interest of backward compatibility we should probably also provide build recipes for (say) an older version of GCC that is supported by all compilers.

-erik

-- 
Erik Schnetter <schnetter at gmail.com>
http://www.perimeterinstitute.ca/personal/eschnetter/

My email is as private as my paper mail. I therefore support encrypting
and signing email messages. Get my PGP key from http://pgp.mit.edu/.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 203 bytes
Desc: Message signed with OpenPGP using GPGMail
Url : http://lists.einsteintoolkit.org/pipermail/users/attachments/20140325/6f162e57/attachment.bin