Issue #284. Use instance hypernyms in all similarity calculations

svn/trunk@8765

nltk/corpus/reader/wordnet.py

@@ -417,7 +417,7 @@ class Synset(_WordNetObject):
         """
         paths = []
 
-        hypernyms = self.hypernyms()
+        hypernyms = self.hypernyms() + self.instance_hypernyms()
         if len(hypernyms) == 0:
             paths = [[self]]
 
@@ -1601,7 +1601,7 @@ def _lcs_by_depth(synset1, synset2, verbose=False):
     # set of subsumers.
 
     eliminated = set()
-    hypernym_relation = lambda s: s.hypernyms()
+    hypernym_relation = lambda s: s.hypernyms() + s.instance_hypernyms()
     for s1 in subsumers:
         for s2 in subsumers:
             if s2 in s1.closure(hypernym_relation):

nltk/test/wordnet.doctest

@@ -502,3 +502,18 @@ Bug 482: Some nouns not being lemmatised by WordNetLemmatizer().lemmatize
     'egg'
     >>> WordNetLemmatizer().lemmatize("legs", pos="n")
     'leg'
+
+Bug 284: instance hypernyms not used in similarity calculations
+
+    >>> wn.synset('john.n.02').lch_similarity(wn.synset('dog.n.01'))
+    1.335...
+    >>> wn.synset('john.n.02').wup_similarity(wn.synset('dog.n.01'))
+    0.571...
+    >>> wn.synset('john.n.02').res_similarity(wn.synset('dog.n.01'), brown_ic)
+    2.224...
+    >>> wn.synset('john.n.02').jcn_similarity(wn.synset('dog.n.01'), brown_ic)
+    0.075...
+    >>> wn.synset('john.n.02').lin_similarity(wn.synset('dog.n.01'), brown_ic)
+    0.252...
+    >>> wn.synset('john.n.02').hypernym_paths()
+    [[Synset('entity.n.01'), ..., Synset('john.n.02')]]