diff --git a/src/exchangeAMRDonors.C b/src/exchangeAMRDonors.C
index e6a6af5..eba12c0 100644
--- a/src/exchangeAMRDonors.C
+++ b/src/exchangeAMRDonors.C
@@ -48,9 +48,6 @@ void tioga::exchangeAMRDonors(void)
   //
   // setup communicator for all to all now
   // since the receiver side is unknown
-  // FIXME:
-  // add sophisticated code later to fix the all_to_all
-  // using MPI-2 standard
   //
   pc_cart->getMap(&nsend_sav,&nrecv_sav,&sndMap,&rcvMap);
   sndMapAll=(int *)malloc(sizeof(int)*pc_cart->numprocs);
@@ -158,6 +155,18 @@ void tioga::exchangeAMRDonors(void)
 	}
       }
     }
+
+  // Remove sends that won't be used. The first 2 ints are obdonors
+  // and obreceptors. If nothing else is being sent, then these won't
+  // be used so we can safely remove them and avoid unnecessary
+  // communication
+  for(int i=0;i<nsend;i++){
+    if((sndPack[i].nints==2) && (sndPack[i].nreals==0)){
+      if (sndPack[i].intData) TIOGA_FREE(sndPack[i].intData);
+      if (sndPack[i].realData) TIOGA_FREE(sndPack[i].realData);
+      sndPack[i].nints=sndPack[i].nreals=0;
+    }
+  }
   //if (myid==0) {
   //for(i=0;i<nsend;i++)
   //  printf("intcount/intcount=%d %d\n",sndPack[i].nints,intcount[i]);
diff --git a/src/parallelComm.C b/src/parallelComm.C
index 9a4684c..b00f246 100644
--- a/src/parallelComm.C
+++ b/src/parallelComm.C
@@ -19,6 +19,8 @@
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 #include "codetypes.h"
 #include "mpi.h"
+#include <algorithm>
+#include <numeric>
 #include "parallelComm.h"
 #define REAL double
 
@@ -26,16 +28,11 @@ void parallelComm::sendRecvPacketsAll(PACKET *sndPack, PACKET *rcvPack)
 {
   int i;
   int *sint,*sreal,*rint,*rreal;
-  int tag,irnum;
-  MPI_Request *request;
-  MPI_Status *status;
   //
   sint=(int *)malloc(sizeof(int)*numprocs);
   sreal=(int *) malloc(sizeof(int)*numprocs);
   rint=(int *)malloc(sizeof(int)*numprocs);
   rreal=(int *) malloc(sizeof(int)*numprocs);
-  request=(MPI_Request *) malloc(sizeof(MPI_Request)*4*numprocs);
-  status=(MPI_Status *) malloc(sizeof(MPI_Status)*4*numprocs);
   //
   for(i=0;i<numprocs;i++){
     sint[i]=sndPack[i].nints;			
@@ -50,49 +47,171 @@ void parallelComm::sendRecvPacketsAll(PACKET *sndPack, PACKET *rcvPack)
     rcvPack[i].nreals=rreal[i];
   }
   //
-  irnum=0;
-  for(i=0;i<numprocs;i++)
-    {
-      if (rcvPack[i].nints > 0) {
-	tag=1;
-	rcvPack[i].intData=(int *) malloc(sizeof(int)*rcvPack[i].nints);
-	MPI_Irecv(rcvPack[i].intData,rcvPack[i].nints,
-		  MPI_INT,i,
-		  tag,scomm,&request[irnum++]);
-      }
-      if (rcvPack[i].nreals > 0) {
-	tag=2;
-	rcvPack[i].realData=(REAL *) malloc(sizeof(REAL)*rcvPack[i].nreals);
-	MPI_Irecv(rcvPack[i].realData,rcvPack[i].nreals,
-		  MPI_DOUBLE,i,
-		  tag,scomm,&request[irnum++]);
-      }
+
+  int all_snd_nints = std::accumulate(sint, sint + numprocs, 0);
+  int all_rcv_nints = std::accumulate(rint, rint + numprocs, 0);
+  int *all_snd_intData, *all_rcv_intData;
+  all_snd_intData=(int *) malloc(sizeof(int)*all_snd_nints);
+  all_rcv_intData=(int *) malloc(sizeof(int)*all_rcv_nints);
+  std::vector<int> snd_int_displs(numprocs+1, 0);
+  std::vector<int> rcv_int_displs(numprocs+1, 0);
+  for (int i=1; i <= numprocs; i++) {
+    snd_int_displs[i] = snd_int_displs[i-1] + sint[i-1];
+    rcv_int_displs[i] = rcv_int_displs[i-1] + rint[i-1];
+  }
+  for (int i=0; i < numprocs; i++) {
+    int displ = snd_int_displs[i];
+    for(int j=0; j < sint[i]; j++){
+      all_snd_intData[displ+j] = sndPack[i].intData[j];
     }
-  for(i=0;i<numprocs;i++)
-    {
-      if (sndPack[i].nints > 0){
-	tag=1;
-	MPI_Isend(sndPack[i].intData,sndPack[i].nints,
-		  MPI_INT,i,
-		  tag,scomm,&request[irnum++]);
-      }
-      if (sndPack[i].nreals > 0){
-	tag=2;
-	MPI_Isend(sndPack[i].realData,sndPack[i].nreals,
-		  MPI_DOUBLE,i,
-		  tag,scomm,&request[irnum++]);
-      }
+  }
+  MPI_Request int_request;
+  MPI_Ialltoallv(all_snd_intData,
+                sint,
+                snd_int_displs.data(),
+                MPI_INT,
+                all_rcv_intData,
+                rint,
+                rcv_int_displs.data(),
+                MPI_INT,
+                scomm,
+                &int_request);
+
+  int all_snd_nreals = std::accumulate(sreal, sreal + numprocs, 0);
+  int all_rcv_nreals = std::accumulate(rreal, rreal + numprocs, 0);
+  REAL *all_snd_realData, *all_rcv_realData;
+  all_snd_realData=(REAL *) malloc(sizeof(REAL)*all_snd_nreals);
+  all_rcv_realData=(REAL *) malloc(sizeof(REAL)*all_rcv_nreals);
+  std::vector<int> snd_real_displs(numprocs+1, 0);
+  std::vector<int> rcv_real_displs(numprocs+1, 0);
+  for (int i=1; i <= numprocs; i++) {
+    snd_real_displs[i] = snd_real_displs[i-1] + sreal[i-1];
+    rcv_real_displs[i] = rcv_real_displs[i-1] + rreal[i-1];
+  }
+  for (int i=0; i < numprocs; i++) {
+    int displ = snd_real_displs[i];
+    for(int j=0; j < sreal[i]; j++){
+      all_snd_realData[displ+j] = sndPack[i].realData[j];
     }
-  MPI_Waitall(irnum,request,status);
-  
+  }
+  MPI_Request real_request;
+  MPI_Ialltoallv(all_snd_realData,
+                sreal,
+                snd_real_displs.data(),
+                MPI_DOUBLE,
+                all_rcv_realData,
+                rreal,
+                rcv_real_displs.data(),
+                MPI_DOUBLE,
+                scomm,
+                &real_request);
+
+  MPI_Wait(&int_request, MPI_STATUS_IGNORE);
+  for(i=0;i<numprocs;i++){
+    if (rcvPack[i].nints > 0) {
+      rcvPack[i].intData=(int *) malloc(sizeof(int)*rcvPack[i].nints);
+    }
+    if (rcvPack[i].nreals > 0) {
+      rcvPack[i].realData=(REAL *) malloc(sizeof(REAL)*rcvPack[i].nreals);
+    }
+  }
+
+  MPI_Wait(&real_request, MPI_STATUS_IGNORE);
+  for (int i=0; i < numprocs; i++) {
+    int displ = rcv_int_displs[i];
+    for(int j=0; j < rint[i]; j++){
+      rcvPack[i].intData[j] = all_rcv_intData[displ+j];
+    }
+  }
+  for (int i=0; i < numprocs; i++) {
+    int displ = rcv_real_displs[i];
+    for(int j=0; j < rreal[i]; j++){
+      rcvPack[i].realData[j] = all_rcv_realData[displ+j];
+    }
+  }
+
+  TIOGA_FREE(all_snd_intData);
+  TIOGA_FREE(all_rcv_intData);
+  TIOGA_FREE(all_snd_realData);
+  TIOGA_FREE(all_rcv_realData);
   TIOGA_FREE(sint);
   TIOGA_FREE(sreal);
   TIOGA_FREE(rint);
   TIOGA_FREE(rreal);
-  TIOGA_FREE(request);
-  TIOGA_FREE(status);
 }
 
+// Old version that does not use ialltoallv
+// void parallelComm::sendRecvPacketsAll(PACKET *sndPack, PACKET *rcvPack)
+// {
+//   int i;
+//   int *sint,*sreal,*rint,*rreal;
+//   int tag,irnum;
+//   MPI_Request *request;
+//   MPI_Status *status;
+//   //
+//   sint=(int *)malloc(sizeof(int)*numprocs);
+//   sreal=(int *) malloc(sizeof(int)*numprocs);
+//   rint=(int *)malloc(sizeof(int)*numprocs);
+//   rreal=(int *) malloc(sizeof(int)*numprocs);
+//   request=(MPI_Request *) malloc(sizeof(MPI_Request)*4*numprocs);
+//   status=(MPI_Status *) malloc(sizeof(MPI_Status)*4*numprocs);
+//   //
+//   for(i=0;i<numprocs;i++){
+//     sint[i]=sndPack[i].nints;			
+//     sreal[i]=sndPack[i].nreals;
+//   }
+//   //
+//   MPI_Alltoall(sint,1,MPI_INT,rint,1,MPI_INT,scomm);
+//   MPI_Alltoall(sreal,1,MPI_INT,rreal,1,MPI_INT,scomm);
+//   //
+//   for(i=0;i<numprocs;i++) {
+//     rcvPack[i].nints=rint[i];
+//     rcvPack[i].nreals=rreal[i];
+//   }
+//   //
+//   irnum=0;
+//   for(i=0;i<numprocs;i++)
+//     {
+//       if (rcvPack[i].nints > 0) {
+// 	tag=1;
+// 	rcvPack[i].intData=(int *) malloc(sizeof(int)*rcvPack[i].nints);
+// 	MPI_Irecv(rcvPack[i].intData,rcvPack[i].nints,
+// 		  MPI_INT,i,
+// 		  tag,scomm,&request[irnum++]);
+//       }
+//       if (rcvPack[i].nreals > 0) {
+// 	tag=2;
+// 	rcvPack[i].realData=(REAL *) malloc(sizeof(REAL)*rcvPack[i].nreals);
+// 	MPI_Irecv(rcvPack[i].realData,rcvPack[i].nreals,
+// 		  MPI_DOUBLE,i,
+// 		  tag,scomm,&request[irnum++]);
+//       }
+//     }
+//   for(i=0;i<numprocs;i++)
+//     {
+//       if (sndPack[i].nints > 0){
+// 	tag=1;
+// 	MPI_Isend(sndPack[i].intData,sndPack[i].nints,
+// 		  MPI_INT,i,
+// 		  tag,scomm,&request[irnum++]);
+//       }
+//       if (sndPack[i].nreals > 0){
+// 	tag=2;
+// 	MPI_Isend(sndPack[i].realData,sndPack[i].nreals,
+// 		  MPI_DOUBLE,i,
+// 		  tag,scomm,&request[irnum++]);
+//       }
+//     }
+//   MPI_Waitall(irnum,request,status);
+  
+//   TIOGA_FREE(sint);
+//   TIOGA_FREE(sreal);
+//   TIOGA_FREE(rint);
+//   TIOGA_FREE(rreal);
+//   TIOGA_FREE(request);
+//   TIOGA_FREE(status);
+// }
+
 void parallelComm::sendRecvPackets(PACKET *sndPack,PACKET *rcvPack)
 {
   int i;