Add alltoall collectives from starmpi

[simgrid.git] / src / smpi / colls / alltoall-pair-one-barrier.c

diff --git a/src/smpi/colls/alltoall-pair-one-barrier.c b/src/smpi/colls/alltoall-pair-one-barrier.c
new file mode 100644 (file)
index 0000000..478b881
--- /dev/null
+++ b/src/smpi/colls/alltoall-pair-one-barrier.c
@@ -0,0 +1,55 @@
+#include "colls.h"
+/*****************************************************************************
+
+ * Function: alltoall_pair
+
+ * Return: int
+
+ * Inputs:
+    send_buff: send input buffer
+    send_count: number of elements to send
+    send_type: data type of elements being sent
+    recv_buff: receive output buffer
+    recv_count: number of elements to received
+    recv_type: data type of elements being received
+    comm: communicator
+
+ * Descrp: Function works when P is power of two. In each phase of P - 1
+           phases, nodes in pair communicate their data.
+
+ * Auther: Ahmad Faraj
+
+ ****************************************************************************/
+int
+smpi_coll_tuned_alltoall_pair_one_barrier(void * send_buff, int send_count, MPI_Datatype send_type,
+                         void * recv_buff, int recv_count, MPI_Datatype recv_type,
+                         MPI_Comm comm)
+{
+
+  MPI_Aint send_chunk, recv_chunk;
+  MPI_Status s;
+  int i, src, dst, rank, num_procs;
+  int tag = 1, success = 1; /*, failure = 0, pof2 = 1; */
+
+  char * send_ptr = (char *) send_buff;
+  char * recv_ptr = (char *) recv_buff;
+  
+  MPI_Comm_rank(comm, &rank);
+  MPI_Comm_size(comm, &num_procs);
+  MPI_Type_extent(send_type, &send_chunk);
+  MPI_Type_extent(recv_type, &recv_chunk);
+
+  send_chunk *= send_count;
+  recv_chunk *= recv_count;  
+
+  MPI_Barrier(comm);
+  for (i = 0; i < num_procs; i++)
+    {
+      src = dst = rank ^ i;     
+      MPI_Sendrecv(send_ptr + dst * send_chunk, send_count, send_type, dst,
+                  tag, recv_ptr + src * recv_chunk, recv_count, recv_type,
+                  src, tag, comm, &s);
+    }
+
+  return success;
+}