dolfin team mailing list archive

[Bartosz Sawicki <sawickib@xxxxxxxxxxxxx>]

On 13/01/09 11:53 AM, Martin Sandve Alnæs wrote:
> On Tue, Jan 13, 2009 at 6:26 PM, Anders Logg <logg@xxxxxxxxx> wrote:
> > On Tue, Jan 13, 2009 at 05:24:41PM +0000, Garth N. Wells wrote:
> > > Anders Logg wrote:
> > > > On Tue, Jan 13, 2009 at 08:45:30AM +0100, Martin Sandve Alnæs wrote:
> > > > > We just discussed that in another thread, and the answer from
> > > > > everybody is yes please, that would be nice. XML file with metadata +
> > > > > raw files with arrays is one solution. And of course, there are many
> > > > > standardized file formats we could support in time for communication
> > > > > with external tools.
> > > > How about sticking everything into the XML file but with some suitable
> > > > tags:
> > > I think that this is what Martin is suggesting. VTK has a file format
> > > like this (although with binary content it is no longer strictly XML as
> > > far as I understand).
> > >
> > > Garth
> > ok, I thought he meant having the data in a separate file.
>
> I did, but I don't care. The advantage of separate binary files
> is that the XML file can be read as a text file, both by humans
> and machines. Also, binary data will have fixed computable
> positions in the pure binary file, which might be useful for ... something?

I also thought about completely binary file, but some XML header can be 
useful for storing informations like element signatures, data types and 
so on.

The most important advantage of binary file is that you can read whole 
vector at once directly into the memory. I'm not sure if XML parsers 
provide such functionality. Usually binary data are encoded in base64 
before placed in XML file (that's what they do in VTK).

Binary storage should be as fast as possible, so we shouldn't care about 
human readability. We have XML for that.


BArtek