add MPI::Comm#Alltoall method

gfd-dennou-club · Apr 21, 2011 · 5ee7294 · 5ee7294
1 parent 7ecdfc6
commit 5ee7294
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diff --git a/ext/mpi/mpi.c b/ext/mpi/mpi.c
@@ -374,6 +374,26 @@ rb_comm_scatter(VALUE self, VALUE rb_sendbuf, VALUE rb_recvbuf, VALUE rb_root)
   return Qnil;
 }
 static VALUE
+rb_comm_alltoall(VALUE self, VALUE rb_sendbuf, VALUE rb_recvbuf)
+{
+  void *sendbuf, *recvbuf;
+  int sendcount, recvcount;
+  MPI_Datatype sendtype, recvtype;
+  int rank, size;
+  struct _Comm *comm;
+  OBJ2C(rb_sendbuf, sendcount, sendbuf, sendtype);
+  Data_Get_Struct(self, struct _Comm, comm);
+  check_error(MPI_Comm_rank(comm->comm, &rank));
+  check_error(MPI_Comm_size(comm->comm, &size));
+  OBJ2C(rb_recvbuf, recvcount, recvbuf, recvtype);
+  if (recvcount < sendcount)
+    rb_raise(rb_eArgError, "recvbuf is too small");
+  recvcount = recvcount/size;
+  sendcount = sendcount/size;
+  check_error(MPI_Alltoall(sendbuf, sendcount, sendtype, recvbuf, recvcount, recvtype, comm->comm));
+  return Qnil;
+}
+static VALUE
 rb_comm_get_Errhandler(VALUE self)
 {
   struct _Comm *comm;
@@ -471,6 +491,7 @@ void Init_mpi()
   rb_define_method(cComm, "Gather", rb_comm_gather, 3);
   rb_define_method(cComm, "Allgather", rb_comm_allgather, 2);
   rb_define_method(cComm, "Scatter", rb_comm_scatter, 3);
+  rb_define_method(cComm, "Alltoall", rb_comm_alltoall, 2);
   rb_define_method(cComm, "Errhandler", rb_comm_get_Errhandler, 0);
   rb_define_method(cComm, "Errhandler=", rb_comm_set_Errhandler, 1);
 

diff --git a/spec/ruby-mpi_spec.rb b/spec/ruby-mpi_spec.rb
@@ -125,6 +125,20 @@
     recvbuf.should eql(rank.to_s*bufsize)
   end
 
+  it "should change data between each others" do
+    world = MPI::Comm::WORLD
+    rank = world.rank
+    size = world.size
+    bufsize = 2
+    sendbuf = rank.to_s*bufsize*size
+    recvbuf = "?"*bufsize*size
+    world.Alltoall(sendbuf, recvbuf)
+    str = ""
+    size.times{|i| str << i.to_s*bufsize}
+    recvbuf.should eql(str)
+  end
+
+
 
 
   it "shoud raise exeption" do