dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Fri, Sep 23, 2011 at 05:26:48PM +0100, Garth N. Wells wrote:
> On 23 September 2011 17:21, Anders Logg <logg@xxxxxxxxx> wrote:
> > On Fri, Sep 23, 2011 at 04:50:33PM +0100, Garth N. Wells wrote:
> >> On 22 September 2011 12:46, Johannes Ring <johannr@xxxxxxxxx> wrote:
> >> > On Wed, Sep 21, 2011 at 1:19 PM, Johannes Ring <johannr@xxxxxxxxx> wrote:
> >> >> On Wed, Sep 21, 2011 at 1:01 PM, Garth N. Wells <gnw20@xxxxxxxxx> wrote:
> >> >>> On 21 September 2011 11:55, Johannes Ring <johannr@xxxxxxxxx> wrote:
> >> >>>> On Wed, Sep 21, 2011 at 12:27 PM, Garth N. Wells <gnw20@xxxxxxxxx> wrote:
> >> >>>>> On 21 September 2011 11:06, Johannes Ring <johannr@xxxxxxxxx> wrote:
> >> >>>>>> On Wed, Sep 21, 2011 at 11:45 AM, Garth N. Wells <gnw20@xxxxxxxxx> wrote:
> >> >>>>>>> A while ago, we used some Boost MPI but then removed it because of
> >> >>>>>>> some older systems lack support. Could we start using it now? I would
> >> >>>>>>> like to. It would make some parallel things a lot simpler. Would the
> >> >>>>>>> buildbots need to be updated?
> >> >>>>>>
> >> >>>>>> Yes, some of them would need an update. Also, we would no longer be
> >> >>>>>> able to provide packages for Ubuntu 10.04 LTS, which is by far the
> >> >>>>>> Ubuntu version with the most downloads from the PPA.
> >> >>>>>>
> >> >>>>>
> >> >>>>> OK, so the decision is whether or not to continue support for 10.04.
> >> >>>>> Since I don't use 10.04 but I do use MPI, I vote for ditching 10.04
> >> >>>>> and using Boost MPI. A compromise would be to use Boost MPI, and not
> >> >>>>> provide parallel support in the 10.04 package.
> >> >>>>>
> >> >>>>> How do we deal with Swig 2 in 10.04? Or is it not required since the
> >> >>>>> wrappers have already been generated?
> >> >>>>
> >> >>>> I have backported SWIG 2.0 to Lucid.
> >> >>>>
> >> >>>
> >> >>> OK,  what about backporting Boost too? There are a few PPAs already, e.g.
> >> >>>
> >> >>>   https://launchpad.net/~infie/+archive/boost-1.47
> >> >>>   https://launchpad.net/~gezakovacs/+archive/boost
> >> >>
> >> >> Yes, I will try to backport Boost in my test PPA
> >> >> (https://launchpad.net/~johannr/+archive/test-ppa). I am just afraid
> >> >> that it will break some of the other packages that depends on the
> >> >> older Boost, but I will give it a shot.
> >> >
> >> > It seems to work out nicely. I only had to rebuild UFC against the new
> >> > Boost packages and then everything ran smoothly.
> >> >
> >> > It will require some work on the buildbots if we start using Boost MPI.
> >> >
> >>
> >> Does anyone else want to throw in an opinion on this?
> >
> > ok for me. Is the plan to keep the MPI:: utility functions and replace
> > the implementation by boost? Or will we be using boost throughout? In
> > particular, does it have a replacement for MPI::distribute?
> >
>
> I suggest keeping the functions in MPI.h.
>
> Boost MPI won't replace MPI::distribute, but it will make the
> internals of  MPI::distribute simpler and more general (e.g. handle
> booleans, which we don't at the moment because they need to be treated
> as a special case).
>
> The two big advantages of Boost MPI are
>
> 1. It's templated, so we don't need *4+* versions of each function
> (uint, int, double, bool, . . .)
> 2. It can handle various C++ STL objects seamlessly.
>
> When do we want to start?

What about speed compared to vanilla MPI?

--
Anders