Re: [help-GIFT] Understanding MRML: Purpose of the "allows-children" element?

[Wolfgang Müller]

On Friday 28 June 2002 15:15, Ralf Juengling wrote:
> Hi,
>
> an "algorithm" might have an "allows-children" element. I didn't get
> the idea, could you explain?
>
> Ralf
Hi,

This is the easiest answer, so this one comes first ;-)

OK. In MRML, you can specify trees of algorithms. This means, you can combine 
your algorithm during runtime from blocks. This is done in GIFT/Viper in 
order to do the separate normalization thing (four feature groups, that are 
combined with equal weights or chosen weights as it is done in Monash). In 
fact, on the demo page, each query is forwarded by a dispatcher (of class 
CQMultiple, if I'm not wrong. To be found in libMRML/cc/CQMultiple.cc, the 
header being in libMRML/include/CQMultiple.h) to four CQInvertedFile (in 
libGIFTQuInvertedFile/....) query engines. These are instances of the same 
class, but differing runtime configuration.

So. The allows-children allows you to specify, what algorithm can have what 
other algorithm as child in the algorithm tree. The same matching is applied 
as when matching query-paradigm tags among collections and algorithms. As 
this tag came later, the default is: all children allowed. Yes, there should 
be something that forbids children, then, so the hottest candidate for that 
is to officially change the default, as (to my knowledge) no client or server 
is using this tag, currently.

Cheers,
Wolfgang