On 06/14/2011 11:33 AM, wenduan wrote:
> anyone can comment on this?
Sorry for the delay, but there were holidays in Germany :)
> On Jun 11, 6:01 pm, wenduan<xuwend...@gmail.com> wrote:
>> Dose cube-growing in jane do hypothesis recombination for sub-spans in
>> the top-down +LM pass? Does it do any threshold pruning for each sub-
>> span as in cube-pruning?
Yes for both questions. The corresponding parameters are
CubeGrow.recombination and CubeGrow.CGBufferThreshold. Note that
threshold pruning is deactivated by default.
>> Does it ever sort the hypotheses generated for a sub-span in the top-
>> down +LM pass? If it does, will it affect the (k-1)th best that has
>> already been produced for a span?
It doesn't sort the hypotheses once they have been selected as "final".
That means that the n-best lists generated at each node are not
necessarily sorted by scores. Re-sorting the hypotheses would also
alter the hypotheses in the nodes above the current one, which already
addressed the generated hypotheses.
>> I'm assuming that in cube-growing that once a hypothesis is enumerated
>> for a node, e.g., it is the first-best for a node according to the
>> heuristic bound, then even if a better node comes by afterwards (after
>> we enumerate more hypotheses), we will still used the first generated
>> first-best. Am I understanding it correctly?
Yes, this is correct. You can use the parameter
CubeGrow.minCGBufferSize to enforce a minimum size of the intermediate
buffer before popping hypotheses out in order to countereffect this, but
in preliminary experiments it didn't seem to bring any improvements.
David Vilar Torres
DFKI GmbH, Alt-Moabit 91c, 10559 Berlin
Tel. (+49) 30 238 95 1845
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