Miles Osborne a écrit :

> Chris is correct --MERT has no guarantees that it will produce the
> same results between runs (even when starting from the same training
> conditions).  This is in part because MERT does not find the global
> optimum (remember it is not considering the full space of possible
> translations, but rather uses n-best lists).

What part of MERT is not deterministic ? Hopefully, there is a way to
make it so (by explicitly initialising the random seed to some known
value, for example). I would feel safer with a fully deterministic
procedure :-] (the first run may be "unpredictable", but any re-run
provides the exact same result). In my experience, this is already the
case. Could it be system-specific, then?

Thanks,
-- Daniel

> However, you can reuse weights between runs for development
> experiments if you are just changing a single feature function.  You
> may not get the best possible results, but your experiments should be
> in the right area. Naturally, you will eventually need to re-run MERT
> to 'sync' your model.
> 
> Miles
> 
> On 21/01/2008, Daniel Déchelotte <[EMAIL PROTECTED]> wrote:
> > Chris Dyer a écrit :
> > > menor bangget a écrit :
> > >
> > > > 2. If I train the same corpus twice, using 2 different word
> > > > alignment, e.g., union and grow-diag-final, will I get different
> > > > weight after running mert-moses.pl; or it will be the same
> > > > because I used exactly the same corpus?
> > >
> > > MERT is a non-deterministic algorithm and so you'll see different
> > > weights from run to run, even with the exact same alignment
> > > heuristics.
> >
> > AFAIK, mert picks some points at random indeed, but it picks the
> > exact same points from run to run (on the same data). In other
> > words, rerunning it on the same models (same data + same training
> > sequence) will provide the same results.

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