[developers] post-reduction lexical gap

Dan Flickinger danf at stanford.edu
Wed Dec 20 09:57:44 CET 2017

Hi Olga,

This error message from ACE occurs when your grammar includes one or more token-mapping (preprocessing) rules which conspire to delete all of the edges from one of the cells in the initial parse chart, so that the parser cannot hope to find a covering analysis.  For the ERG, this occasionally happens when I adjust the rules for inserting lexical entries for unknown words, and then try to filter some of those added entries in case I already have a "native" entry for that word.  I imagine you must have one or more rules in a file like the ERG's "lfr.tdl" which discard some unwanted entries before parsing.  Try commenting out these rules and see if the error message for that sentence disappears. You can see the error just by trying to parse that one sentence directly with ACE.


From: developers-bounces at emmtee.net <developers-bounces at emmtee.net> on behalf of Olga Zamaraeva <olzama at uw.edu>
Sent: Tuesday, December 19, 2017 11:07 PM
To: Woodley Packard
Cc: developers at delph-in.net
Subject: Re: [developers] post-reduction lexical gap

Hi Woodley,

At a risk of asking a basic question: What does a lexical gap mean?

Thank you,
On Tue, Dec 19, 2017 at 9:35 PM Woodley Packard <sweaglesw at sweaglesw.org<mailto:sweaglesw at sweaglesw.org>> wrote:
Hi all,

This means ACE encountered a lexical gap.  It should not be a rare occurrence, at least on non-toy data.

Best, Woodley

On Dec 19, 2017, at 1:21 PM, Stephan Oepen <oe at ifi.uio.no<mailto:oe at ifi.uio.no>> wrote:

hi olga,

this looks like an error message from the parsing client, not [incr tsdb()] proper.  i would guess maybe ACE?  if so, woodley will likely be able to shed more light on this question :-).

best, oe

On Tue, 19 Dec 2017 at 19:19 Olga Zamaraeva <olzama at uw.edu<mailto:olzama at uw.edu>> wrote:
Dear developers,

What does the message "post-reduction lexical gap" mean in the context of adding an [ incr tsdb() ] profile for regression testing to the Grammar Matrix?

Here's the type of line that we sometimes see in home/gold/mytest/parse

10 at 1@10 at -1@0 at -1@0 at 0@-1 at 0@0 at -1@0 at -1@-1 at -1@-1 at -1@-1 at -1@-1 at -1@-1 at 0@0 at 0@0 at 0@-1 at -1@-1 at -1@34728 at -1@-1 at -1@23-6-2013 14:28:24 at post-reduction lexical gap@

This seems problematic but we don't really know what it is at this point.

(Here's a related topic on Discourse: https://delphinqa.ling.washington.edu/t/no-parses-when-adding-regression-tests/81/7)

Thank you,
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