[developers] Regarding to German sentence analysis.

[Michael Wayne Goodman]

Hi Megha,

I'm the main developer of PyDelphin. It is not the canonical tool for
MRS-DMRS conversion (that is the LKB), but I think it might be the most
commonly used for the task.

Install it like this (commands begin after $):

    $ pip install pydelphin

Then you can convert (Simple)MRS to DMRS like this:

    $ delphin convert --from simplemrs --to dmrx
every-student-reads-a-book.mrs
    <dmrs-list><dmrs cfrom="-1" cto="-1">...</dmrs></dmrs-list>

You can convert from DMRS to MRS like this:

    $ delphin convert --from dmrx --to simplemrs
every-student-reads-a-book.xml
    [ TOP: h0 RELS: <...> HCONS: <...>]

Details on conversion:

In well-formed and algebra-compliant MRSs (i.e. from a well-behaved
grammar), conversion to and from DMRS should be lossless. Note that
losslessness does not imply string equivalency, but the meaning will be the
same.

In MRS<->DMRS conversion, the following is a partial list of situations
I've seen that can cause problems:

* 2+ elementary predications (EPs) sharing an intrinsic variable (ARG0)
* EPs without an ARG0
* scoping problems (e.g. an EP is qeq'd to its own label)
* disconnected MRSs (some EP does not have an argument, or is not the
argument of, or does not share a scope (i.e. label) with any other EP in
the graph starting at TOP)
* Coindexation of unexpressed EPs in MRS (e.g. i-variables standing for
dropped arguments) cannot be recovered when round-tripping to DMRS

These are simply bad MRSs, and we don't guarantee to produce an equally bad
DMRS.

Also, individual constraints (ICONS) are a relatively new feature in MRSs,
and we have not yet implemented a solution in DMRS, so those will be lost.

There are some other edge cases that never come up in practice.

I hope this was useful and informative. Please let me know if anything is
unclear.

On Mon, Feb 20, 2017 at 9:05 AM, Woodley Packard <sweaglesw at sweaglesw.org>
wrote:

>
> Megha,
>
> I believe PyDelphin is the tool you will want to use for that conversion.
> I am forwarding your inquiry to the Delphin developers list, since my own
> tools and expertise do not directly bear on your question.  I believe there
> are people on list who can help though.  Can you give examples of the DMRSs
> you are having trouble with and let us know where they came from?
>
> Thanks, Woodley
>
>
> > On Feb 20, 2017, at 2:50 AM, megha jain <jain11megha at gmail.com> wrote:
> >
> > Hello.
> >
> > I want to ask details about conversion from MRS to DMRS and DMRS to MRS.
> >
> > In many sentences it is easy to convert from MRS to DMRS from the
> package already available but problem comes while DMRS to MRS conversion.
> >
> > Can you let me know the approach comes in use or code which handles it.
> >
> > I dropped a mail to Berthold Cryssman as you suggested me but couldn't
> get any response till now.
> >
> > Please do respond.
> >
> > Thank You.
>
>


-- 
Michael Wayne Goodman
Ph.D. Candidate, UW Linguistics
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