[Dune] Fwd: Re: Communicating IdSet elements

[Martin Nolte]

;-)

-------- Original Message --------
Subject: Re: [Dune] Communicating IdSet elements
Date: Sun, 24 Jul 2011 17:09:29 +0200
From: Martin Nolte <nolte at mathematik.uni-freiburg.de>
To: Jö Fahlke <jorrit at jorrit.de>

Hi Jö,

with respect to disk I/O the lack of precision was indented. I guess having a
good binary representation is all you need to achieve both, communication and
any kind of disk I/O (you can always write in in base64 or hexadecimal
encoding into a character stream). But I wanted to keep an open discussion at
the current state.

As to the communication: Maybe Markus can give further insights on the current
status, here. Moreover, I think there might be some good ideas in the MPI
standard that can also help for arbitrary serialization problems (read: disk
I/O above).

Best,

Martin

On 07/24/2011 04:52 PM, Jö Fahlke wrote:
> Am Sun, 24. Jul 2011, 16:31:27 +0200 schrieb Martin Nolte:
>> Either way, I think we need to add two important properties a global id has to
>> satisfy:
>> 1) there must be an easy way to communicate it
> 
> As long as you're using a CollectiveCommunication, this currently works by
> communicating the bit pattern as far as I know.  While this works in practise,
> there is no guarantee that it will work for any type of id someone could
> possibly think of, and of course it is hackish.
> 
>> 2) it needs to support (disk) I/O
> 
> I think we need to be more precise here: writing the id to a text file is as
> easy as providing operator<<() (and operator>>() for reading).
> 
> When you think of stuff like checkpointing however, you probably want to have
> a way to store the Id in a binary representation to save space and thus speed
> up writing.  This calls more for a general serialization framework, and indeed
> that would also help to achieve safe communication.
> 
> Bye,
> Jö.
> 

-- 
Martin Nolte <nolte at mathematik.uni-freiburg.de>

Universität Freiburg                                   phone: +49-761-203-5630
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