Grammar Engineering Frequently Asked Questions
How do I do interactive unification?
This FAQ explains how to do interactive unification. To learn about when to use interactive unification, see this FAQ
. If you've tried interactive unification, and you're not getting the result you expect, look here
- In the chart, click on each of the daughter edges, and select "feature structure" to get the feature structures for the edges. (Interactive unification can also be used to debug a unary rule. Here I'm going to talk about binary rules.)
- In the LKB top menu, choose View > Grammar Rule and pick the rule you think should have applied. This will give you a feature structure for the rule.
- In the feature structure for the rule, scroll down until you find the HEAD-DTR feature (it may be easier to shrink the values for SYNSEM, ARGS, and C-CONT on the way).
- Click on the type that is the value of HEAD-DTR (probably sign, but possibly something more specific), and choose "select" out of the pop-up menu.
- In the feature structure for the edge that should be the head daughter, click on the highest type (e.g., common-noun-lex or head-comp-phrase) and in the pop-up menu choose "unify".
- If the unification failed already, there will be a message in the LKB window telling you the first point at which the two feature structures didn't unify (there may be more).
- The rules tend to be fairly non-specific, so this first unification usually works. If it does, you'll get a new window called "unification result" which is exactly the information from the rule with the information of the head daughter unified in.
- In the unification result feature structure, scroll down (or shrink down) to the NON-HEAD-DTR feature. Click on the value of that feature and choose "select".
- In the feature structure for the edge that should be the non-head daughter, click on the highest type (e.g., det-lex or head-spec-phrase) and choose "unify".
- Go look at the LKB top window for a message indicating the first point at which the two feature structures didn't unify (there may be more). This information should be useful for debugging.
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- 02 Nov 2004
Topic revision: r1 - 2004-11-03 - 04:55:36 - TWikiGuest