From 83468b17d60d40df0280988ff04731db64a33294 Mon Sep 17 00:00:00 2001
From: Mridul Seth <seth.mridul@gmail.com>
Date: Thu, 6 Oct 2016 23:32:01 +0530
Subject: [PATCH] Correct logic for iterating over SimilarityABC

---
 CHANGELOG.md                     | 1 +
 gensim/interfaces.py             | 7 ++-----
 gensim/test/test_similarities.py | 9 +++++++++
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2f7ef32f59..615e677607 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ Changes
 * Fixed issue #838, RuntimeWarning: overflow encountered in exp  (@markroxor, [#895](https://github.com/RaRe-Technologies/gensim/pull/895))
 *  Changed some log messages to warnings as suggested in issue #828. (@rhnvrm, [#884](https://github.com/RaRe-Technologies/gensim/pull/884))
 *  Fixed issue #851, In summarizer.py, RunTimeError is raised if single sentence input is provided to avoid ZeroDivionError. (@metalaman, #887)
+* Fixed issue [#791](https://github.com/RaRe-Technologies/gensim/issues/791), correct logic for iterating over SimilarityABC interface. ([@MridulS](https://github.com/MridulS), [#839](https://github.com/RaRe-Technologies/gensim/pull/839)
 
 
 0.13.2, 2016-08-19
diff --git a/gensim/interfaces.py b/gensim/interfaces.py
index cd5d6ee495..e1024723b0 100644
--- a/gensim/interfaces.py
+++ b/gensim/interfaces.py
@@ -261,11 +261,8 @@ def __iter__(self):
                 # scipy.sparse happy
                 chunk_end = min(self.index.shape[0], chunk_start + self.chunksize)
                 chunk = self.index[chunk_start : chunk_end]
-                if chunk.shape[0] > 1:
-                    for sim in self[chunk]:
-                        yield sim
-                else:
-                    yield self[chunk]
+                for sim in self[chunk]:
+                    yield sim
         else:
             for doc in self.index:
                 yield self[doc]
diff --git a/gensim/test/test_similarities.py b/gensim/test/test_similarities.py
index 9d6ea599a2..87740862a4 100644
--- a/gensim/test/test_similarities.py
+++ b/gensim/test/test_similarities.py
@@ -432,6 +432,15 @@ def testMmapCompressed(self):
         # to be mmaped!
 
 
+    def testChunksize(self):
+        index = self.cls(None, corpus, num_features=len(dictionary), shardsize=5)
+        expected = [sim for sim in index]
+        index.chunksize = len(index) - 1
+        sims = [sim for sim in index]
+        self.assertTrue(numpy.allclose(expected, sims))
+        index.destroy()
+
+
 class TestWord2VecAnnoyIndexer(unittest.TestCase):
 
     def setUp(self):