Add collectives for allgather, allreduce, bcast and reduce

[simgrid.git] / src / smpi / colls / reduce-binomial.c

diff --git a/src/smpi/colls/reduce-binomial.c b/src/smpi/colls/reduce-binomial.c
new file mode 100644 (file)
index 0000000..580e3db
--- /dev/null
+++ b/src/smpi/colls/reduce-binomial.c
@@ -0,0 +1,51 @@
+#include "colls.h"
+
+//#include <star-reduction.c>
+
+int smpi_coll_tuned_reduce_binomial(void *sendbuf, void *recvbuf, int count,
+                                    MPI_Datatype datatype, MPI_Op op, int root,
+                                    MPI_Comm comm)
+{
+  MPI_Status status;
+  int comm_size, rank;
+  int mask, relrank, source;
+  int dst;
+  int tag = 4321;
+  MPI_Aint extent;
+  void *tmp_buf;
+
+  if (count == 0)
+    return 0;
+  MPI_Comm_rank(comm, &rank);
+  MPI_Comm_size(comm, &comm_size);
+
+  MPI_Type_extent(datatype, &extent);
+
+  tmp_buf = (void *) malloc(count * extent);
+
+  MPI_Sendrecv(sendbuf, count, datatype, rank, tag,
+               recvbuf, count, datatype, rank, tag, comm, &status);
+  mask = 1;
+  relrank = (rank - root + comm_size) % comm_size;
+
+  while (mask < comm_size) {
+    /* Receive */
+    if ((mask & relrank) == 0) {
+      source = (relrank | mask);
+      if (source < comm_size) {
+        source = (source + root) % comm_size;
+        MPI_Recv(tmp_buf, count, datatype, source, tag, comm, &status);
+        star_reduction(op, tmp_buf, recvbuf, &count, &datatype);
+      }
+    } else {
+      dst = ((relrank & (~mask)) + root) % comm_size;
+      MPI_Send(recvbuf, count, datatype, dst, tag, comm);
+      break;
+    }
+    mask <<= 1;
+  }
+
+  free(tmp_buf);
+
+  return 0;
+}