InteractiveUnify < Main

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---+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 [[MissingEdge][this FAQ]].  If you've tried interactive unification, and you're not getting the result you expect, look [[UnifySurprise][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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-- EmilyBender - 02 Nov 2004
Topic revision: r1 - 2004-11-03 - TWikiGuest