Emcee bugfix patch

gistfile1.txt

diff --git a/emcee/utils.py b/emcee/utils.py
index c5685d3..0aa63c7 100644
--- a/emcee/utils.py
+++ b/emcee/utils.py
@@ -163,19 +163,25 @@ if MPI is not None:
             F = _function_wrapper(function)
 
             # Tell all the workers what function to use.
+            requests = []
+
             for i in range(self.size):
-                self.comm.isend(F, dest=i + 1)
+                r=self.comm.isend(F, dest=i + 1)
+                requests.append(r)
+            MPI.Request.waitall(requests)
 
             # Send all the tasks off. Do not wait for them to be received,
             # just continue.
+            requests = []
             for i, task in enumerate(tasks):
                 worker = i % self.size + 1
                 if self.debug:
                     print(u"Sent task {0} to worker {1} with tag {2}."
                             .format(task, worker, i))
-                self.comm.isend(task, dest=worker, tag=i)
+                r=self.comm.isend(task, dest=worker, tag=i)
+                requests.append(r)
             results = []
-
+            MPI.Request.waitall(requests)
             # Now wait for the answers.
             for i in range(ntask):
                 worker = i % self.size + 1