Add negative feedback option to Rocchio

pyserini/search/lucene/__main__.py

@@ -88,6 +88,7 @@ def define_search_args(parser):
 
     parser.add_argument('--rm3', action='store_true', help="Use RM3")
     parser.add_argument('--rocchio', action='store_true', help="Use Rocchio")
+    parser.add_argument('--usenegative', action='store_true', help="Use nonrelevant labels in Rocchio")
     parser.add_argument('--qld', action='store_true', help="Use QLD")
 
     parser.add_argument('--language', type=str, help='language code for BM25, e.g. zh for Chinese', default='en')
@@ -182,7 +183,10 @@ def define_search_args(parser):
 
     if args.rocchio:
         search_rankers.append('rocchio')
-        searcher.set_rocchio()
+        if args.usenegative:
+            searcher.set_rocchio(rocchio_gamma=0.15, rocchio_use_negative=True)
+        else:
+            searcher.set_rocchio()
 
     fields = dict()
     if args.fields:

pyserini/search/lucene/_searcher.py

@@ -241,7 +241,7 @@ def is_using_rm3(self) -> bool:
         """Check if RM3 query expansion is being performed."""
         return self.object.useRM3()
 
-    def set_rocchio(self, top_fb_terms=10, top_fb_docs=10, bottom_fb_terms=10, bottom_fb_docs=10, rocchio_alpha=1, rocchio_beta=0.75, rocchio_gamma=0, rocchio_output_query=False):
+    def set_rocchio(self, top_fb_terms=10, top_fb_docs=10, bottom_fb_terms=10, bottom_fb_docs=10, rocchio_alpha=1, rocchio_beta=0.75, rocchio_gamma=0, rocchio_output_query=False, rocchio_use_negative=False):
         """Configure Rocchio query expansion.
 
         Parameters
@@ -262,9 +262,11 @@ def set_rocchio(self, top_fb_terms=10, top_fb_docs=10, bottom_fb_terms=10, botto
             Rocchio parameter for weight to assign to the nonrelevant document vector.
         rocchio_output_query : bool
             Print the original and expanded queries as debug output.
+        rocchio_use_negative : bool
+            Rocchio parameter to use negative labels.
         """
         if self.object.reader.getTermVectors(0):
-            self.object.setRocchio(top_fb_terms, top_fb_docs, bottom_fb_terms, bottom_fb_docs, rocchio_alpha, rocchio_beta, rocchio_gamma, rocchio_output_query)
+            self.object.setRocchio(top_fb_terms, top_fb_docs, bottom_fb_terms, bottom_fb_docs, rocchio_alpha, rocchio_beta, rocchio_gamma, rocchio_output_query, rocchio_use_negative)
         else:
             raise TypeError("Rocchio is not supported for indexes without document vectors.")
 

tests/test_search.py

@@ -262,7 +262,7 @@ def test_rocchio(self):
         self.assertAlmostEqual(hits[9].score, 4.21740, places=5)
 
         self.searcher.set_rocchio(top_fb_terms=10, top_fb_docs=8, bottom_fb_terms=10, 
-            bottom_fb_docs=8, rocchio_alpha=0.4, rocchio_beta=0.5, rocchio_gamma=0.1)
+            bottom_fb_docs=8, rocchio_alpha=0.4, rocchio_beta=0.5, rocchio_gamma=0.1, rocchio_output_query=False, rocchio_use_negative=True)
         self.assertTrue(self.searcher.is_using_rocchio())
 
         hits = self.searcher.search('information retrieval')
@@ -272,6 +272,17 @@ def test_rocchio(self):
         self.assertEqual(hits[9].docid, 'CACM-1032')
         self.assertAlmostEqual(hits[9].score, 2.57510, places=5)
 
+        self.searcher.set_rocchio(top_fb_terms=10, top_fb_docs=8, bottom_fb_terms=10, 
+            bottom_fb_docs=8, rocchio_alpha=0.4, rocchio_beta=0.5, rocchio_gamma=0.1, rocchio_output_query=False, rocchio_use_negative=False)
+        self.assertTrue(self.searcher.is_using_rocchio())
+
+        hits = self.searcher.search('information retrieval')
+
+        self.assertEqual(hits[0].docid, 'CACM-3134')
+        self.assertAlmostEqual(hits[0].score, 4.03900, places=5)
+        self.assertEqual(hits[9].docid, 'CACM-1032')
+        self.assertAlmostEqual(hits[9].score, 2.91550, places=5)
+
         with self.assertRaises(TypeError):
             self.no_vec_searcher.set_rocchio()