Added a few things to the NCCL communicator (#503)

pySDC/helpers/NCCL_communicator.py

@@ -27,7 +27,7 @@ class NCCLComm(object):
         Args:
             Name (str): Name of the requested attribute
         """
-        if name not in ['size', 'rank', 'Get_rank', 'Get_size', 'Split']:
+        if name not in ['size', 'rank', 'Get_rank', 'Get_size', 'Split', 'Create_cart', 'Is_inter', 'Get_topology']:
             cp.cuda.get_current_stream().synchronize()
 
         return getattr(self.commMPI, name)
@@ -71,6 +71,26 @@ class NCCLComm(object):
         else:
             raise NotImplementedError('Don\'t know what NCCL operation to use to replace this MPI operation!')
 
+    def reduce(self, sendobj, op=MPI.SUM, root=0):
+        sync = False
+        if hasattr(sendobj, 'data'):
+            if hasattr(sendobj.data, 'ptr'):
+                sync = True
+        if sync:
+            cp.cuda.Device().synchronize()
+
+        return self.commMPI.reduce(sendobj, op=op, root=root)
+
+    def allreduce(self, sendobj, op=MPI.SUM):
+        sync = False
+        if hasattr(sendobj, 'data'):
+            if hasattr(sendobj.data, 'ptr'):
+                sync = True
+        if sync:
+            cp.cuda.Device().synchronize()
+
+        return self.commMPI.allreduce(sendobj, op=op)
+
     def Reduce(self, sendbuf, recvbuf, op=MPI.SUM, root=0):
         if not hasattr(sendbuf.data, 'ptr'):
             return self.commMPI.Reduce(sendbuf=sendbuf, recvbuf=recvbuf, op=op, root=root)
@@ -113,3 +133,7 @@ class NCCLComm(object):
         stream = cp.cuda.get_current_stream()
 
         self.commNCCL.bcast(buff=buf.data.ptr, count=count, datatype=dtype, root=root, stream=stream.ptr)
+
+    def Barrier(self):
+        cp.cuda.get_current_stream().synchronize()
+        self.commMPI.Barrier()