Defined non-blocking version of PSB_SUM.

base/modules/Makefile

@@ -375,7 +375,7 @@ psblas/psb_s_psblas_mod.o psblas/psb_c_psblas_mod.o psblas/psb_d_psblas_mod.o ps
 
 psb_base_mod.o: $(MODULES)
 
-penv/psi_penv_mod.o: penv/psi_penv_mod.F90 psb_const_mod.o serial/psb_vect_mod.o serial/psb_mat_mod.o
+penv/psi_penv_mod.o: penv/psi_penv_mod.F90 psb_const_mod.o serial/psb_vect_mod.o serial/psb_mat_mod.o desc/psb_desc_const_mod.o
 	$(FC)   $(FINCLUDES) $(FDEFINES) $(FCOPT) $(EXTRA_OPT) -c $< -o $@
 
 psb_penv_mod.o: psb_penv_mod.F90 $(COMMINT) $(BASIC_MODS)

base/modules/desc/psb_desc_const_mod.f90

@@ -48,6 +48,9 @@ module psb_desc_const_mod
   ! The following are bit fields. 
   integer(psb_ipk_), parameter :: psb_swap_send_=1, psb_swap_recv_=2
   integer(psb_ipk_), parameter :: psb_swap_sync_=4, psb_swap_mpi_=8
+  integer(psb_ipk_), parameter :: psb_collective_start_=1, psb_collective_end_=2
+  integer(psb_ipk_), parameter :: psb_collective_sync_=4
+
   ! Choice among lists on which to base data exchange
   integer(psb_ipk_), parameter :: psb_no_comm_=-1
   integer(psb_ipk_), parameter :: psb_comm_halo_=1, psb_comm_ovr_=2

base/modules/penv/psi_c_collective_mod.F90

@@ -31,6 +31,7 @@
 !    
 module psi_c_collective_mod
   use psi_penv_mod
+  use psb_desc_const_mod
   
 
   interface psb_sum
@@ -79,7 +80,7 @@ contains
   ! SUM
   !
 
-  subroutine psb_csums(ctxt,dat,root)
+  subroutine psb_csums(ctxt,dat,root,mode,request)
 #ifdef MPI_MOD
     use mpi
 #endif
@@ -90,10 +91,15 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     complex(psb_spk_), intent(inout)  :: dat
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
     complex(psb_spk_) :: dat_
-    integer(psb_mpk_) :: iam, np, info, icomm
+    integer(psb_mpk_) :: iam, np, info
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -104,17 +110,41 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call mpi_allreduce(dat,dat_,1,psb_mpi_c_spk_,mpi_sum,icomm,info)
+        call mpi_allreduce(MPI_IN_PLACE,dat,1,psb_mpi_c_spk_,mpi_sum,icomm,info)
-      dat = dat_
       else
-      call mpi_reduce(dat,dat_,1,psb_mpi_c_spk_,mpi_sum,root_,icomm,info)
+        call mpi_reduce(MPI_IN_PLACE,dat,1,psb_mpi_c_spk_,mpi_sum,root_,icomm,info)
-      if (iam == root_) dat = dat_
+      endif
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          call mpi_iallreduce(MPI_IN_PLACE,dat,1,psb_mpi_c_spk_,mpi_sum,icomm,request,info)
+        else
+          call mpi_ireduce(MPI_IN_PLACE,dat,1,psb_mpi_c_spk_,mpi_sum,root_,icomm,request,info)
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      end if
     end if
 #endif    
   end subroutine psb_csums
 
-  subroutine psb_csumv(ctxt,dat,root)
+  subroutine psb_csumv(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -126,10 +156,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     complex(psb_spk_), intent(inout)  :: dat(:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    complex(psb_spk_), allocatable :: dat_(:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
 
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -140,25 +174,55 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_c_spk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_spk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_spk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_c_spk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_spk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_c_spk_,mpi_sum,root_,icomm,info)
         end if
       end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_spk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_spk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_spk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      endif
+    end if
+    
 #endif    
   end subroutine psb_csumv
 
-  subroutine psb_csumm(ctxt,dat,root)
+  subroutine psb_csumm(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -170,10 +234,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     complex(psb_spk_), intent(inout)  :: dat(:,:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    complex(psb_spk_), allocatable :: dat_(:,:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
 
@@ -185,19 +253,48 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_c_spk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_spk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_spk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_c_spk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_spk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_c_spk_,mpi_sum,root_,icomm,info)
+        end if
+      end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_spk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_spk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_spk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
       endif
     end if
 #endif    

base/modules/penv/psi_d_collective_mod.F90

@@ -31,6 +31,7 @@
 !    
 module psi_d_collective_mod
   use psi_penv_mod
+  use psb_desc_const_mod
   
   interface psb_max
     module procedure psb_dmaxs, psb_dmaxv, psb_dmaxm
@@ -441,7 +442,7 @@ contains
   ! SUM
   !
 
-  subroutine psb_dsums(ctxt,dat,root)
+  subroutine psb_dsums(ctxt,dat,root,mode,request)
 #ifdef MPI_MOD
     use mpi
 #endif
@@ -452,10 +453,15 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     real(psb_dpk_), intent(inout)  :: dat
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
     real(psb_dpk_) :: dat_
-    integer(psb_mpk_) :: iam, np, info, icomm
+    integer(psb_mpk_) :: iam, np, info
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -466,17 +472,41 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call mpi_allreduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_sum,icomm,info)
+        call mpi_allreduce(MPI_IN_PLACE,dat,1,psb_mpi_r_dpk_,mpi_sum,icomm,info)
-      dat = dat_
       else
-      call mpi_reduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_sum,root_,icomm,info)
+        call mpi_reduce(MPI_IN_PLACE,dat,1,psb_mpi_r_dpk_,mpi_sum,root_,icomm,info)
-      if (iam == root_) dat = dat_
+      endif
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          call mpi_iallreduce(MPI_IN_PLACE,dat,1,psb_mpi_r_dpk_,mpi_sum,icomm,request,info)
+        else
+          call mpi_ireduce(MPI_IN_PLACE,dat,1,psb_mpi_r_dpk_,mpi_sum,root_,icomm,request,info)
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      end if
     end if
 #endif    
   end subroutine psb_dsums
 
-  subroutine psb_dsumv(ctxt,dat,root)
+  subroutine psb_dsumv(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -488,10 +518,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     real(psb_dpk_), intent(inout)  :: dat(:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    real(psb_dpk_), allocatable :: dat_(:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
 
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -502,25 +536,55 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,icomm,info)
         end if
       end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      endif
+    end if
+    
 #endif    
   end subroutine psb_dsumv
 
-  subroutine psb_dsumm(ctxt,dat,root)
+  subroutine psb_dsumm(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -532,10 +596,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     real(psb_dpk_), intent(inout)  :: dat(:,:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    real(psb_dpk_), allocatable :: dat_(:,:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
 
@@ -547,19 +615,48 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,icomm,info)
+        end if
+      end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
       endif
     end if
 #endif    

base/modules/penv/psi_e_collective_mod.F90

@@ -31,6 +31,7 @@
 !    
 module psi_e_collective_mod
   use psi_penv_mod
+  use psb_desc_const_mod
   
   interface psb_max
     module procedure psb_emaxs, psb_emaxv, psb_emaxm
@@ -349,7 +350,7 @@ contains
   ! SUM
   !
 
-  subroutine psb_esums(ctxt,dat,root)
+  subroutine psb_esums(ctxt,dat,root,mode,request)
 #ifdef MPI_MOD
     use mpi
 #endif
@@ -360,10 +361,15 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     integer(psb_epk_), intent(inout)  :: dat
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
     integer(psb_epk_) :: dat_
-    integer(psb_mpk_) :: iam, np, info, icomm
+    integer(psb_mpk_) :: iam, np, info
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -374,17 +380,41 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call mpi_allreduce(dat,dat_,1,psb_mpi_epk_,mpi_sum,icomm,info)
+        call mpi_allreduce(MPI_IN_PLACE,dat,1,psb_mpi_epk_,mpi_sum,icomm,info)
-      dat = dat_
       else
-      call mpi_reduce(dat,dat_,1,psb_mpi_epk_,mpi_sum,root_,icomm,info)
+        call mpi_reduce(MPI_IN_PLACE,dat,1,psb_mpi_epk_,mpi_sum,root_,icomm,info)
-      if (iam == root_) dat = dat_
+      endif
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          call mpi_iallreduce(MPI_IN_PLACE,dat,1,psb_mpi_epk_,mpi_sum,icomm,request,info)
+        else
+          call mpi_ireduce(MPI_IN_PLACE,dat,1,psb_mpi_epk_,mpi_sum,root_,icomm,request,info)
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      end if
     end if
 #endif    
   end subroutine psb_esums
 
-  subroutine psb_esumv(ctxt,dat,root)
+  subroutine psb_esumv(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -396,10 +426,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     integer(psb_epk_), intent(inout)  :: dat(:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    integer(psb_epk_), allocatable :: dat_(:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
 
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -410,25 +444,55 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_epk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_epk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_epk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_epk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_epk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_epk_,mpi_sum,root_,icomm,info)
         end if
       end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_epk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_epk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_epk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      endif
+    end if
+    
 #endif    
   end subroutine psb_esumv
 
-  subroutine psb_esumm(ctxt,dat,root)
+  subroutine psb_esumm(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -440,10 +504,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     integer(psb_epk_), intent(inout)  :: dat(:,:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    integer(psb_epk_), allocatable :: dat_(:,:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
 
@@ -455,19 +523,48 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_epk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_epk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_epk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_epk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_epk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_epk_,mpi_sum,root_,icomm,info)
+        end if
+      end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_epk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_epk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_epk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
       endif
     end if
 #endif    

base/modules/penv/psi_i2_collective_mod.F90

@@ -31,6 +31,7 @@
 !    
 module psi_i2_collective_mod
   use psi_penv_mod
+  use psb_desc_const_mod
   
   interface psb_max
     module procedure psb_i2maxs, psb_i2maxv, psb_i2maxm
@@ -349,7 +350,7 @@ contains
   ! SUM
   !
 
-  subroutine psb_i2sums(ctxt,dat,root)
+  subroutine psb_i2sums(ctxt,dat,root,mode,request)
 #ifdef MPI_MOD
     use mpi
 #endif
@@ -360,10 +361,15 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     integer(psb_i2pk_), intent(inout)  :: dat
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
     integer(psb_i2pk_) :: dat_
-    integer(psb_mpk_) :: iam, np, info, icomm
+    integer(psb_mpk_) :: iam, np, info
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -374,17 +380,41 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call mpi_allreduce(dat,dat_,1,psb_mpi_i2pk_,mpi_sum,icomm,info)
+        call mpi_allreduce(MPI_IN_PLACE,dat,1,psb_mpi_i2pk_,mpi_sum,icomm,info)
-      dat = dat_
       else
-      call mpi_reduce(dat,dat_,1,psb_mpi_i2pk_,mpi_sum,root_,icomm,info)
+        call mpi_reduce(MPI_IN_PLACE,dat,1,psb_mpi_i2pk_,mpi_sum,root_,icomm,info)
-      if (iam == root_) dat = dat_
+      endif
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          call mpi_iallreduce(MPI_IN_PLACE,dat,1,psb_mpi_i2pk_,mpi_sum,icomm,request,info)
+        else
+          call mpi_ireduce(MPI_IN_PLACE,dat,1,psb_mpi_i2pk_,mpi_sum,root_,icomm,request,info)
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      end if
     end if
 #endif    
   end subroutine psb_i2sums
 
-  subroutine psb_i2sumv(ctxt,dat,root)
+  subroutine psb_i2sumv(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -396,10 +426,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     integer(psb_i2pk_), intent(inout)  :: dat(:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    integer(psb_i2pk_), allocatable :: dat_(:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
 
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -410,25 +444,55 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_i2pk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_i2pk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_i2pk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_i2pk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_i2pk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_i2pk_,mpi_sum,root_,icomm,info)
         end if
       end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_i2pk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_i2pk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_i2pk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      endif
+    end if
+    
 #endif    
   end subroutine psb_i2sumv
 
-  subroutine psb_i2summ(ctxt,dat,root)
+  subroutine psb_i2summ(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -440,10 +504,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     integer(psb_i2pk_), intent(inout)  :: dat(:,:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    integer(psb_i2pk_), allocatable :: dat_(:,:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
 
@@ -455,19 +523,48 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_i2pk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_i2pk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_i2pk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_i2pk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_i2pk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_i2pk_,mpi_sum,root_,icomm,info)
+        end if
+      end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_i2pk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_i2pk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_i2pk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
       endif
     end if
 #endif    

base/modules/penv/psi_m_collective_mod.F90

@@ -31,6 +31,7 @@
 !    
 module psi_m_collective_mod
   use psi_penv_mod
+  use psb_desc_const_mod
   
   interface psb_max
     module procedure psb_mmaxs, psb_mmaxv, psb_mmaxm
@@ -349,7 +350,7 @@ contains
   ! SUM
   !
 
-  subroutine psb_msums(ctxt,dat,root)
+  subroutine psb_msums(ctxt,dat,root,mode,request)
 #ifdef MPI_MOD
     use mpi
 #endif
@@ -360,10 +361,15 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     integer(psb_mpk_), intent(inout)  :: dat
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
     integer(psb_mpk_) :: dat_
-    integer(psb_mpk_) :: iam, np, info, icomm
+    integer(psb_mpk_) :: iam, np, info
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -374,17 +380,41 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call mpi_allreduce(dat,dat_,1,psb_mpi_mpk_,mpi_sum,icomm,info)
+        call mpi_allreduce(MPI_IN_PLACE,dat,1,psb_mpi_mpk_,mpi_sum,icomm,info)
-      dat = dat_
       else
-      call mpi_reduce(dat,dat_,1,psb_mpi_mpk_,mpi_sum,root_,icomm,info)
+        call mpi_reduce(MPI_IN_PLACE,dat,1,psb_mpi_mpk_,mpi_sum,root_,icomm,info)
-      if (iam == root_) dat = dat_
+      endif
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          call mpi_iallreduce(MPI_IN_PLACE,dat,1,psb_mpi_mpk_,mpi_sum,icomm,request,info)
+        else
+          call mpi_ireduce(MPI_IN_PLACE,dat,1,psb_mpi_mpk_,mpi_sum,root_,icomm,request,info)
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      end if
     end if
 #endif    
   end subroutine psb_msums
 
-  subroutine psb_msumv(ctxt,dat,root)
+  subroutine psb_msumv(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -396,10 +426,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     integer(psb_mpk_), intent(inout)  :: dat(:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    integer(psb_mpk_), allocatable :: dat_(:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
 
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -410,25 +444,55 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_mpk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_mpk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_mpk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_mpk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_mpk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_mpk_,mpi_sum,root_,icomm,info)
         end if
       end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_mpk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_mpk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_mpk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      endif
+    end if
+    
 #endif    
   end subroutine psb_msumv
 
-  subroutine psb_msumm(ctxt,dat,root)
+  subroutine psb_msumm(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -440,10 +504,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     integer(psb_mpk_), intent(inout)  :: dat(:,:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    integer(psb_mpk_), allocatable :: dat_(:,:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
 
@@ -455,19 +523,48 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_mpk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_mpk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_mpk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_mpk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_mpk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_mpk_,mpi_sum,root_,icomm,info)
+        end if
+      end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_mpk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_mpk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_mpk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
       endif
     end if
 #endif    

base/modules/penv/psi_s_collective_mod.F90

@@ -31,6 +31,7 @@
 !    
 module psi_s_collective_mod
   use psi_penv_mod
+  use psb_desc_const_mod
   
   interface psb_max
     module procedure psb_smaxs, psb_smaxv, psb_smaxm
@@ -441,7 +442,7 @@ contains
   ! SUM
   !
 
-  subroutine psb_ssums(ctxt,dat,root)
+  subroutine psb_ssums(ctxt,dat,root,mode,request)
 #ifdef MPI_MOD
     use mpi
 #endif
@@ -452,10 +453,15 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     real(psb_spk_), intent(inout)  :: dat
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
     real(psb_spk_) :: dat_
-    integer(psb_mpk_) :: iam, np, info, icomm
+    integer(psb_mpk_) :: iam, np, info
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -466,17 +472,41 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call mpi_allreduce(dat,dat_,1,psb_mpi_r_spk_,mpi_sum,icomm,info)
+        call mpi_allreduce(MPI_IN_PLACE,dat,1,psb_mpi_r_spk_,mpi_sum,icomm,info)
-      dat = dat_
       else
-      call mpi_reduce(dat,dat_,1,psb_mpi_r_spk_,mpi_sum,root_,icomm,info)
+        call mpi_reduce(MPI_IN_PLACE,dat,1,psb_mpi_r_spk_,mpi_sum,root_,icomm,info)
-      if (iam == root_) dat = dat_
+      endif
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          call mpi_iallreduce(MPI_IN_PLACE,dat,1,psb_mpi_r_spk_,mpi_sum,icomm,request,info)
+        else
+          call mpi_ireduce(MPI_IN_PLACE,dat,1,psb_mpi_r_spk_,mpi_sum,root_,icomm,request,info)
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      end if
     end if
 #endif    
   end subroutine psb_ssums
 
-  subroutine psb_ssumv(ctxt,dat,root)
+  subroutine psb_ssumv(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -488,10 +518,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     real(psb_spk_), intent(inout)  :: dat(:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    real(psb_spk_), allocatable :: dat_(:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
 
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -502,25 +536,55 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_spk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_spk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_spk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_spk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_spk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_spk_,mpi_sum,root_,icomm,info)
         end if
       end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_spk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_spk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_spk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      endif
+    end if
+    
 #endif    
   end subroutine psb_ssumv
 
-  subroutine psb_ssumm(ctxt,dat,root)
+  subroutine psb_ssumm(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -532,10 +596,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     real(psb_spk_), intent(inout)  :: dat(:,:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    real(psb_spk_), allocatable :: dat_(:,:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
 
@@ -547,19 +615,48 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_spk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_spk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_spk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_spk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_spk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_spk_,mpi_sum,root_,icomm,info)
+        end if
+      end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_spk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_spk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_r_spk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
       endif
     end if
 #endif    

base/modules/penv/psi_z_collective_mod.F90

@@ -31,6 +31,7 @@
 !    
 module psi_z_collective_mod
   use psi_penv_mod
+  use psb_desc_const_mod
   
 
   interface psb_sum
@@ -79,7 +80,7 @@ contains
   ! SUM
   !
 
-  subroutine psb_zsums(ctxt,dat,root)
+  subroutine psb_zsums(ctxt,dat,root,mode,request)
 #ifdef MPI_MOD
     use mpi
 #endif
@@ -90,10 +91,15 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     complex(psb_dpk_), intent(inout)  :: dat
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
     complex(psb_dpk_) :: dat_
-    integer(psb_mpk_) :: iam, np, info, icomm
+    integer(psb_mpk_) :: iam, np, info
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -104,17 +110,41 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call mpi_allreduce(dat,dat_,1,psb_mpi_c_dpk_,mpi_sum,icomm,info)
+        call mpi_allreduce(MPI_IN_PLACE,dat,1,psb_mpi_c_dpk_,mpi_sum,icomm,info)
-      dat = dat_
       else
-      call mpi_reduce(dat,dat_,1,psb_mpi_c_dpk_,mpi_sum,root_,icomm,info)
+        call mpi_reduce(MPI_IN_PLACE,dat,1,psb_mpi_c_dpk_,mpi_sum,root_,icomm,info)
-      if (iam == root_) dat = dat_
+      endif
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          call mpi_iallreduce(MPI_IN_PLACE,dat,1,psb_mpi_c_dpk_,mpi_sum,icomm,request,info)
+        else
+          call mpi_ireduce(MPI_IN_PLACE,dat,1,psb_mpi_c_dpk_,mpi_sum,root_,icomm,request,info)
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      end if
     end if
 #endif    
   end subroutine psb_zsums
 
-  subroutine psb_zsumv(ctxt,dat,root)
+  subroutine psb_zsumv(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -126,10 +156,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     complex(psb_dpk_), intent(inout)  :: dat(:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    complex(psb_dpk_), allocatable :: dat_(:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
 
 #if !defined(SERIAL_MPI)
     call psb_info(ctxt,iam,np)
@@ -140,25 +174,55 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_c_dpk_,mpi_sum,root_,icomm,info)
         end if
       end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
+      endif
+    end if
+    
 #endif    
   end subroutine psb_zsumv
 
-  subroutine psb_zsumm(ctxt,dat,root)
+  subroutine psb_zsumm(ctxt,dat,root,mode,request)
     use psb_realloc_mod
 #ifdef MPI_MOD
     use mpi
@@ -170,10 +234,14 @@ contains
     type(psb_ctxt_type), intent(in)              :: ctxt
     complex(psb_dpk_), intent(inout)  :: dat(:,:)
     integer(psb_mpk_), intent(in), optional    :: root
+    integer(psb_ipk_), intent(in), optional    :: mode
+    integer(psb_mpk_), intent(inout), optional :: request
     integer(psb_mpk_) :: root_
-    complex(psb_dpk_), allocatable :: dat_(:,:)
+    integer(psb_mpk_) :: iam, np,  info
-    integer(psb_mpk_) :: iam, np,  info, icomm
+    integer(psb_mpk_) :: icomm
+    integer(psb_mpk_) :: status(mpi_status_size)
     integer(psb_ipk_) :: iinfo
+    logical :: collective_start, collective_end, collective_sync
     
 #if !defined(SERIAL_MPI)
 
@@ -185,19 +253,48 @@ contains
       root_ = -1
     endif
     icomm = psb_get_mpi_comm(ctxt)
+    if (present(mode)) then
+      collective_sync = .false.
+      collective_start = iand(mode,psb_collective_start_) /= 0
+      collective_end = iand(mode,psb_collective_end_) /= 0
+      if (.not.present(request)) then
+        collective_sync = .true.
+        collective_start = .false.
+        collective_end = .false.
+      end if
+    else
+      collective_sync = .true.
+      collective_start = .false.
+      collective_end = .false.      
+    end if
+    if (collective_sync) then 
       if (root_ == -1) then 
-      call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
-      dat_ = dat
         if (iinfo == psb_success_) &
-           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,icomm,info)
+             & call mpi_allreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,icomm,info)
       else
         if (iam == root_) then 
-        call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,root_,icomm,info)
-        dat_ = dat
-        call mpi_reduce(dat_,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,root_,icomm,info)
         else
-        call psb_realloc(1,1,dat_,iinfo)
+          call mpi_reduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,root_,icomm,info)
-        call mpi_reduce(dat,dat_,size(dat),psb_mpi_c_dpk_,mpi_sum,root_,icomm,info)
+        end if
+      end if
+    else
+      if (collective_start) then
+        if (root_ == -1) then 
+          if (iinfo == psb_success_) &
+               & call mpi_iallreduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,&
+               & icomm,request,info)
+        else
+          if (iam == root_) then 
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          else
+            call mpi_ireduce(MPI_IN_PLACE,dat,size(dat),psb_mpi_c_dpk_,mpi_sum,root_,&
+                 & icomm,request,info)
+          end if
+        end if
+      else if (collective_end) then
+        call mpi_wait(request,status,info)
       endif
     end if
 #endif