[developers] cfrom/cto in MRS

[Paul Haley]

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
>>
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