From f0f04372539073e0ae9d48b908fa905a0f741ac0 2013-08-14 03:24:46
From: Samuel Ainsworth <samuel_ainsworth@brown.edu>
Date: 2013-08-14 03:24:46
Subject: [PATCH] Fix parallel.client.View map() on numpy arrays

---

diff --git a/IPython/parallel/client/remotefunction.py b/IPython/parallel/client/remotefunction.py
index 07e9327..4b31a0b 100644
--- a/IPython/parallel/client/remotefunction.py
+++ b/IPython/parallel/client/remotefunction.py
@@ -232,7 +232,8 @@ class ParallelFunction(RemoteFunction):
             for seq in sequences:
                 part = self.mapObject.getPartition(seq, index, nparts, maxlen)
                 args.append(part)
-            if not any(args):
+
+            if sum([len(arg) for arg in args]) == 0:
                 continue
 
             if self._mapping:
diff --git a/IPython/parallel/tests/test_view.py b/IPython/parallel/tests/test_view.py
index 7a3540e..b44994b 100644
--- a/IPython/parallel/tests/test_view.py
+++ b/IPython/parallel/tests/test_view.py
@@ -344,6 +344,18 @@ class TestView(ClusterTestCase, ParametricTestCase):
         it = iter(arr)
         r = view.map_sync(lambda x:x, arr)
         self.assertEqual(r, list(arr))
+
+    @skip_without('numpy')
+    def test_map_numpy(self):
+        """test map on numpy arrays (direct)"""
+        import numpy
+        from numpy.testing.utils import assert_array_equal
+
+        view = self.client[:]
+        # 101 is prime, so it won't be evenly distributed
+        arr = numpy.arange(101)
+        r = view.map_sync(lambda x: x, arr)
+        assert_array_equal(r, arr)
     
     def test_scatter_gather_nonblocking(self):
         data = range(16)