[Kaldi-users] LM rescoring problem

[Mailing l. u. f. U. C. a. U. <kal...@li...>]

Hi,

I have a problem concerning LM rescoring - when trying to obtain decoded
utterance with following pipeline:

lattice-lmrescore --lm-scale=-1.0 ark:out.lat G_old.fst ark:- | \
lattice-lmrescore --lm-scale=1.0 ark:- G_new.fst ark:- | \
lattice-scale --inv_acoustic-scale=10 ark:- ark:- | \
lattice-best-path --word-symbol-table=words.txt ark:- ark,t:- | \
int2sym.pl -f 2- words.txt | \
sed 's/<UNK>//' > out.utt

a warning displays:
> Empty lattice for utterance 001-001 (incompatible LM?)

HCLG is of course built with G_old.fst which is unigram version of
G_new.fst. Both share the same lexicon. I get expected results when
omitting lmrescore part.
What is weird, when i try to substitute G_new.fst with G_old.fst (to get
"kind of" an identity transform), same warning occurs.
Am I missing something?

I don't know if it is relevant, but my AM is SGMM2 on top of LDA+MLLT.

Marcin
tv...@gm...