[SRILM User List] question about lattice-tool

[Andreas Stolcke]

What I call "scores"  are usually log likelihoods or log probabilities, 
sometimes scaled in some fashion.   lattice-tool does not care about the 
probabilistic interpretation of such scores, it just combines the scores 
according to their weights and finds the path with the highest overall 
score.

In the case of HTK lattices, the scores typically encoded in the 
lattices are acoustic model (a=), ngram model (n=), general language 
model (l=), and sometimes pronunciation weights (r=).
The HTK lattice format has been generalized to allow up to 9 additional 
scores to be encoded (x1= through x9=) on nodes or links.

The header of the lattice file can define the weights for these scores 
(acscale=, ngscale=, lmscale=, prscale=).  There is also a word 
insertion penalty (wdpenalty=) that implies a constant additional score 
on each word hypothesis.

Score weights can be overridden on the command line (-htk-scscale, 
-htk-lmscale, etc.).  If no score weights are given they default to 1 
(or 0 for the word penalty).

If you specify an external language model that will override the l= 
(general lm) scores in the lattice, but that is optional.

lattice-tool will generate an aggregate score from the weighted 
combination of all scores, and decode the lattice path with the highest 
overall score (from both nodes and links).

Andreas


On 6/6/2018 2:44 PM, Andreas Stolcke wrote:
>
> *From:* Michael Campbell <mcampbell at veritone.com>
> *Sent:* Wednesday, June 6, 2018 2:31 PM
> *To:* Andreas Stolcke <Andreas.Stolcke at microsoft.com>
> *Subject:* Re: question about lattice-tool
>
> By scores, you mean probabilities of words?
>
> The lattice I input consists of edges representing multiple word 
> candidates per time step = node.  I use the HTK lattice format and do 
> not assign any probabilities to edges in my lattice.
>
> For example,
>
> /         __their_____         /            \ 
>        *----there----*---going---*    t=0 \____they're_/t=1        t=2/
> I thought lattice-tool would choose the path of highest probability 
> based on a built-in language model.  For example, that it would 
> produce output from above as "they're going" since it would have the 
> highest probability.
> It is interesting that lattice-tool *does* produce output for such a 
> lattice (without probabilities or scores).  How does it compute that 
> output?
> best,
> Mike
>
> On Wed, Jun 6, 2018 at 1:27 PM, Andreas Stolcke 
> <Andreas.Stolcke at microsoft.com <mailto:Andreas.Stolcke at microsoft.com>> 
> wrote:
>
>     Michael,
>
>     Lattice-tool does not require a language model.   If non is given,
>     the scores contained in the lattice will be used for decoding
>     (-viterbi-decode, -nbest-decode, -posterior-decode) and confusion
>     network building (-write-mesh).
>
>     Andreas
>
>     *From:* Michael Campbell <mcampbell at veritone.com
>     <mailto:mcampbell at veritone.com>>
>     *Sent:* Wednesday, June 6, 2018 1:10 PM
>     *To:* Andreas Stolcke <Andreas.Stolcke at microsoft.com
>     <mailto:Andreas.Stolcke at microsoft.com>>
>     *Subject:* question about lattice-tool
>
>     Hello Andreas,
>
>     I am using the SRILM "lattice-tool" utility, for which you are
>     listed as an author.
>
>     I am new to this, and the documentation does not say whether or
>     not "lattice-tool" requires
>
>     a Language Model to be input in order to use Viterbi or Posterior
>     algorithms on a lattice of words.
>
>        * I created a lattice of words, and would like to see the most
>     probable sentence.
>
>        * If I use Viterbi, I get a result, *without using any language
>     model options*.
>
>     *Does "lattice-tool" use a built-in language model to give that
>     result, or is the result 'nonsense' since I am not inputting a
>     language model into "lattice-tool"? *
>
>     Thank you very much for any feedback.
>
>     All the best,
>
>     Mike
>
>     -- 
>
>     *Michael Campbell*
>     mcampbell at veritone.com <mailto:youremail at veritone.com>
>
>     Veritone
>     <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.veritone.com%2F&data=02%7C01%7Candreas.stolcke%40microsoft.com%7C5372e4261e8a4949118308d5cbe9845f%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C1%7C636639126171722470&sdata=%2B%2FgJZobo%2ByG2E1qfHJv44L41%2FCM2TeTDOos4YonJpBE%3D&reserved=0>
>     *Veritone, Inc.*
>     575 Anton Blvd. Suite 100, Costa Mesa, CA. 92626
>     <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmaps.google.com%2F%3Fq%3D575%2BAnton%2BBlvd.%2BSuite%2B100%2C%2BCosta%2BMesa%2C%2BCA.%2B92626%26entry%3Dgmail%26source%3Dg&data=02%7C01%7CAndreas.Stolcke%40microsoft.com%7C62343e8765c0435d255208d5cbf4bda3%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636639174377239258&sdata=6z1l6Q9HvpZaRao5lfZoBLIbPTNchLm2Nw0tdpqVN2Y%3D&reserved=0>
>     https://na01.safelinks.protection.outlook.com/?url=www.veritone.com&data=01%7C01%7Csrilm-user%40speech.sri.com%7Cd43ee031eadb4929012708d5cbfa90ed%7C40779d3379c44626b8bf140c4d5e9075%7C1&sdata=leasVxlXPPmSvkLLUyPUppLnez%2Fox14XFBVDXArFfhw%3D&reserved=0
>     <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.veritone.com%2F&data=02%7C01%7Candreas.stolcke%40microsoft.com%7C5372e4261e8a4949118308d5cbe9845f%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C1%7C636639126171732475&sdata=LJFiuKplRH9lC%2BY%2Fy6tDc9jNvRIcJKD7UC7AdpYiMVE%3D&reserved=0>
>
>
>
> -- 
>
> *Michael Campbell*
> mcampbell at veritone.com <mailto:youremail at veritone.com>
>
> Veritone 
> <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.veritone.com%2F&data=02%7C01%7CAndreas.Stolcke%40microsoft.com%7C62343e8765c0435d255208d5cbf4bda3%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636639174377239258&sdata=eKT48dBBohsLkdUtK7zvfH9qto7l4YEymlGFkzFyLkI%3D&reserved=0>
> *Veritone, Inc.*
> 575 Anton Blvd. Suite 100, Costa Mesa, CA. 92626
> https://na01.safelinks.protection.outlook.com/?url=www.veritone.com&data=01%7C01%7Csrilm-user%40speech.sri.com%7Cd43ee031eadb4929012708d5cbfa90ed%7C40779d3379c44626b8bf140c4d5e9075%7C1&sdata=leasVxlXPPmSvkLLUyPUppLnez%2Fox14XFBVDXArFfhw%3D&reserved=0 
> <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.veritone.com%2F&data=02%7C01%7CAndreas.Stolcke%40microsoft.com%7C62343e8765c0435d255208d5cbf4bda3%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636639174377249272&sdata=6a3lUiV%2BQ%2B4fWOu0zF813u52Ken1Vz8aRdYt%2FZsezVw%3D&reserved=0>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.speech.sri.com/pipermail/srilm-user/attachments/20180606/da704b41/attachment.html>