[developers] cfrom/cto in MRS

[Rebecca Dridan]

Hi Paul,

To the best of my knowledge, using PET with the ERG without
chart-mapping is basically deprecated now. Among other things, the
characterisation information you want is passed up using chart-mapping
rules.

If I understand correctly, you want to parse utterances containing
unknown words without using a POS tagger? That's not a default setup
(and will probably lead to very slow parsing), so I think you would
need to add appropriate chart-mapping rules to the grammar to get that
behaviour.  Or maybe I am misunderstanding your goal?

Rebecca

On Fri, Mar 30, 2012 at 18:55, Paul Haley <paul at haleyai.com> wrote:
> Here's a dump of the issue, FYI.
>
>
> Essentially, PET appears not to maintain the MRS linkage to tokens if either
> generics are involved or chart mapping is not used, which seems
> inappropriate in either case.
>
>
> With chart mapping, undefined words are not recognized:
>
> build/debug/cheap/cheap (0.99.14svn_cm $Change: 850 $) -nsolutions=1
> -verbose=4 -mrs=new -default-les=all -cm ../ERG/english.grm
>
> Eukaryotic cells contain mitochondria.
> ...
> no lexicon entries for:
>     "eukaryotic"
>     "mitochondria."
> ...
>
> Without chart mapping the words are recognized but the MRS loses reference
> to the chart (i.e., by token position):
>
> Eukaryotic cells contain mitochondria.
> ...
> <mrs>
> <label vid='1'/><var vid='2'/>
> <ep cfrom='-1' cto='-1'><pred>UNKNOWN_REL</pred><label vid='1'/>
> ...
>
> The following shows that when the words are known to the ERG the MRS has the
> position information in chart mapping mode:
>
> this is a test.
> ...
> <mrs>
> <label vid='1'/><var vid='2'/>
> <ep cfrom='0' cto='1'><pred>GENERIC_ENTITY_REL</pred><label vid='3'/>
> ...
>
> Thanks again, and sorry for omitting the detail from the prior email.
>
> Paul
>
>
> On 03/30/2012 11:55 AM, Paul Haley wrote:
>
> Hello again,
>
> I was able to isolate the change in my environment to the use of the chart
> mapping option.
>
> Apparently, the from/to attributes of the MRS (shown here around a colon)
> are -1 unless chart-mapping is selected:
>
>     [ LTOP: h1  INDEX: e2 [ e SF: PROP TENSE: PAST MOOD: INDICATIVE PROG: -
> PERF: - ]  RELS: <   [ appos_rel<0:36>
>
> I dropped the -cm intending to receive the explosion of generics discussed
> in the "unknown word handling and chart mapping section" of
> http://moin.delph-in.net/PetInput.
>
> This was intentional since we are looking at the chart in detail, extracting
> "insights" from PET/ERG, and for this reason want (as much) mapping
> information from MRS to the chart (as practical).
>
> The from/to is helpful, but more direct linkage between elementary
> predications and the chart would be even better.
>
> Regards,
> Paul
>
> P.S. We send FSC, too, and would appreciate advice or examples on how to
> constrain those with deeper semantics (as in the excellent discussion at
> http://moin.delph-in.net/SuquamishMRSWordNet).)
>
>
> On 03/29/2012 02:18 PM, Paul Haley wrote:
>
> Greetings,
>
>
>
> I would appreciate any advice on how to get the cfrom/cto information output
> in the new MRS with the latest PET and ERG.
>
>
>
> Thank you,
>
> Paul
>
>
>
> Paul Haley
>
> Automata, Inc.
>
> (412) 716-6420
>
>