diff --git a/Changelog b/Changelog
index db182a03..08e950bb 100644
--- a/Changelog
+++ b/Changelog
@@ -2,6 +2,11 @@ Changelog. A lot less detailed than usual, at least for past
 history. 
 
 
+2007/01/23: Defined new field ext_index in desc_type, and
+	    fixed long standing inconsistency in usage of overlap for
+	    AS preconditioners. Modified halo to accept selector for
+	    halo_index vs. ext_index.
+
 2007/01/11: Migrated repository to SVN. 
 
 2007/01/11: MLD2P4 has been moved to the new org. Now tackling the 
diff --git a/base/comm/psb_ihalo.f90 b/base/comm/psb_ihalo.f90
index 520c7134..43a89742 100644
--- a/base/comm/psb_ihalo.f90
+++ b/base/comm/psb_ihalo.f90
@@ -46,12 +46,12 @@
 !   tran      -  character(optional).          ???.
 !   mode      -  integer(optional).
 !
-subroutine  psb_ihalom(x,desc_a,info,alpha,jx,ik,work,tran,mode)
+subroutine  psb_ihalom(x,desc_a,info,alpha,jx,ik,work,tran,mode,data)
   use psb_descriptor_type
   use psb_const_mod
   use psi_mod
-  use psb_realloc_mod
   use psb_check_mod
+  use psb_realloc_mod
   use psb_error_mod
   use psb_penv_mod
   implicit none
@@ -61,13 +61,13 @@ subroutine  psb_ihalom(x,desc_a,info,alpha,jx,ik,work,tran,mode)
   integer, intent(out)                     :: info
   real(kind(1.d0)), intent(in), optional   :: alpha
   integer, intent(inout), optional, target :: work(:)
-  integer, intent(in), optional            :: mode,jx,ik
+  integer, intent(in), optional            :: mode,jx,ik,data
   character, intent(in), optional          :: tran
 
   ! locals
   integer                  :: ictxt, np, me, &
        & err_act, m, n, iix, jjx, ix, ijx, nrow, k, maxk, liwork,&
-       & imode, err
+       & imode, err,data_
   integer, pointer         :: xp(:,:), iwork(:)
   character                :: ltran
   character(len=20)        :: name, ch_err
@@ -116,6 +116,14 @@ subroutine  psb_ihalom(x,desc_a,info,alpha,jx,ik,work,tran,mode)
   else
     ltran = 'N'
   endif
+
+  if (present(data)) then     
+    data_ = data
+  else
+    data_ = psb_comm_halo_
+  endif
+
+
   if (present(mode)) then 
     imode = mode
   else
@@ -179,7 +187,7 @@ subroutine  psb_ihalom(x,desc_a,info,alpha,jx,ik,work,tran,mode)
   ! exchange halo elements
   if(ltran.eq.'N') then
     call psi_swapdata(imode,k,0,xp,&
-         & desc_a,iwork,info)
+         & desc_a,iwork,info,data=data_)
   else if((ltran.eq.'T').or.(ltran.eq.'H')) then
     call psi_swaptran(imode,k,1,xp,&
          & desc_a,iwork,info)
@@ -253,12 +261,12 @@ end subroutine psb_ihalom
 !   tran      -  character(optional).          ???.
 !   mode      -  integer(optional).
 !
-subroutine  psb_ihalov(x,desc_a,info,alpha,work,tran,mode)
+subroutine  psb_ihalov(x,desc_a,info,alpha,work,tran,mode,data)
   use psb_descriptor_type
   use psb_const_mod
   use psi_mod
-  use psb_realloc_mod
   use psb_check_mod
+  use psb_realloc_mod
   use psb_error_mod
   use psb_penv_mod
   implicit none
@@ -268,13 +276,13 @@ subroutine  psb_ihalov(x,desc_a,info,alpha,work,tran,mode)
   integer, intent(out)                     :: info
   real(kind(1.d0)), intent(in), optional   :: alpha
   integer, intent(inout), optional, target :: work(:)
-  integer, intent(in), optional            :: mode
+  integer, intent(in), optional            :: mode,data
   character, intent(in), optional          :: tran
 
   ! locals
   integer                  :: ictxt, np, me,&
        & err_act, m, n, iix, jjx, ix, ijx, nrow, imode,&
-       & err, liwork
+       & err, liwork, data_
   integer,pointer          :: iwork(:)
   character                :: ltran
   character(len=20)        :: name, ch_err
@@ -309,6 +317,11 @@ subroutine  psb_ihalov(x,desc_a,info,alpha,work,tran,mode)
   else
     ltran = 'N'
   endif
+  if (present(data)) then     
+    data_ = data
+  else
+    data_ = psb_comm_halo_
+  endif
   if (present(mode)) then 
     imode = mode
   else
@@ -367,7 +380,7 @@ subroutine  psb_ihalov(x,desc_a,info,alpha,work,tran,mode)
   ! exchange halo elements
   if(ltran.eq.'N') then
     call psi_swapdata(imode,0,x(iix:size(x)),&
-         & desc_a,iwork,info)
+         & desc_a,iwork,info,data=data_)
   else if((ltran.eq.'T').or.(ltran.eq.'H')) then
     call psi_swaptran(imode,1,x(iix:size(x)),&
          & desc_a,iwork,info)
diff --git a/base/comm/psb_zhalo.f90 b/base/comm/psb_zhalo.f90
index 937cba8c..8f05b014 100644
--- a/base/comm/psb_zhalo.f90
+++ b/base/comm/psb_zhalo.f90
@@ -45,7 +45,7 @@
 !   tran      -  character(optional).          ???.
 !   mode      -  integer(optional).
 !
-subroutine  psb_zhalom(x,desc_a,info,alpha,jx,ik,work,tran,mode)
+subroutine  psb_zhalom(x,desc_a,info,alpha,jx,ik,work,tran,mode,data)
   use psb_descriptor_type
   use psb_const_mod
   use psi_mod
@@ -60,13 +60,13 @@ subroutine  psb_zhalom(x,desc_a,info,alpha,jx,ik,work,tran,mode)
   integer, intent(out)                      :: info
   complex(kind(1.d0)), intent(in), optional    :: alpha
   complex(kind(1.d0)), optional, target        :: work(:)
-  integer, intent(in), optional             :: mode,jx,ik
+  integer, intent(in), optional             :: mode,jx,ik,data
   character, intent(in), optional           :: tran
 
   ! locals
   integer                  :: ictxt, np, me, &
        & err_act, m, n, iix, jjx, ix, ijx, k, maxk, nrow, imode, i,&
-       & err, liwork
+       & err, liwork,data_
   complex(kind(1.d0)),pointer :: iwork(:), xp(:,:)
   character                :: ltran
   character(len=20)        :: name, ch_err
@@ -121,6 +121,12 @@ subroutine  psb_zhalom(x,desc_a,info,alpha,jx,ik,work,tran,mode)
     imode = IOR(psb_swap_send_,psb_swap_recv_)
   endif
 
+  if (present(data)) then     
+    data_ = data
+  else
+    data_ = psb_comm_halo_
+  endif
+
   ! check vector correctness
   call psb_chkvect(m,1,size(x,1),ix,ijx,desc_a,info,iix,jjx)
   if(info.ne.0) then
@@ -177,7 +183,7 @@ subroutine  psb_zhalom(x,desc_a,info,alpha,jx,ik,work,tran,mode)
   xp => x(iix:size(x,1),jjx:jjx+k-1)
   if(ltran.eq.'N') then
     call psi_swapdata(imode,k,zzero,xp,&
-         & desc_a,iwork,info,data=psb_comm_halo_)
+         & desc_a,iwork,info,data=data_)
   else if((ltran.eq.'T').or.(ltran.eq.'H')) then
     call psi_swaptran(imode,k,zone,xp,&
          &desc_a,iwork,info)
@@ -252,7 +258,7 @@ end subroutine psb_zhalom
 !   tran      -  character(optional).          ???.
 !   mode      -  integer(optional).
 !
-subroutine  psb_zhalov(x,desc_a,info,alpha,work,tran,mode)
+subroutine  psb_zhalov(x,desc_a,info,alpha,work,tran,mode,data)
   use psb_descriptor_type
   use psb_const_mod
   use psi_mod
@@ -267,12 +273,12 @@ subroutine  psb_zhalov(x,desc_a,info,alpha,work,tran,mode)
   integer, intent(out)                      :: info
   complex(kind(1.d0)), intent(in), optional    :: alpha
   complex(kind(1.d0)), target, optional        :: work(:)
-  integer, intent(in), optional             :: mode
+  integer, intent(in), optional             :: mode,data
   character, intent(in), optional           :: tran
 
   ! locals
   integer                  :: ictxt, np, me, err_act, &
-       & m, n, iix, jjx, ix, ijx, nrow, imode, err, liwork
+       & m, n, iix, jjx, ix, ijx, nrow, imode, err, liwork,data_
   complex(kind(1.d0)),pointer :: iwork(:)
   character                :: ltran
   character(len=20)        :: name, ch_err
@@ -311,6 +317,12 @@ subroutine  psb_zhalov(x,desc_a,info,alpha,work,tran,mode)
     imode = IOR(psb_swap_send_,psb_swap_recv_)
   endif
 
+  if (present(data)) then     
+    data_ = data
+  else
+    data_ = psb_comm_halo_
+  endif
+
   ! check vector correctness
   call psb_chkvect(m,1,size(x,1),ix,ijx,desc_a,info,iix,jjx)
   if(info.ne.0) then
@@ -363,7 +375,7 @@ subroutine  psb_zhalov(x,desc_a,info,alpha,work,tran,mode)
   ! exchange halo elements
   if(ltran.eq.'N') then
     call psi_swapdata(imode,zzero,x(iix:size(x)),&
-         & desc_a,iwork,info,data=psb_comm_halo_)
+         & desc_a,iwork,info,data=data_)
   else if((ltran.eq.'T').or.(ltran.eq.'H')) then
     call psi_swaptran(imode,zone,x(iix:size(x)),&
          & desc_a,iwork,info)
diff --git a/base/modules/psb_comm_mod.f90 b/base/modules/psb_comm_mod.f90
index eb54841f..928bd9b0 100644
--- a/base/modules/psb_comm_mod.f90
+++ b/base/modules/psb_comm_mod.f90
@@ -86,44 +86,44 @@ module psb_comm_mod
        integer, intent(in), optional             :: mode,data
        character, intent(in), optional           :: tran
      end subroutine psb_dhalov
-     subroutine  psb_ihalom(x,desc_a,info,alpha,jx,ik,work,tran,mode)
+     subroutine  psb_ihalom(x,desc_a,info,alpha,jx,ik,work,tran,mode,data)
        use psb_descriptor_type
        integer, intent(inout) :: x(:,:)
        type(psb_desc_type), intent(in)        :: desc_a
        integer, intent(out)                   :: info
        real(kind(1.d0)), intent(in), optional :: alpha
        integer, intent(inout), optional       :: work(:)
-       integer, intent(in), optional          :: mode,jx,ik
+       integer, intent(in), optional          :: mode,jx,ik,data
        character, intent(in), optional        :: tran
      end subroutine psb_ihalom
-     subroutine  psb_ihalov(x,desc_a,info,alpha,work,tran,mode)
+     subroutine  psb_ihalov(x,desc_a,info,alpha,work,tran,mode,data)
        use psb_descriptor_type
        integer, intent(inout)                 :: x(:)
        type(psb_desc_type), intent(in)        :: desc_a
        integer, intent(out)                   :: info
        real(kind(1.d0)), intent(in), optional :: alpha
        integer, intent(inout), optional       :: work(:)
-       integer, intent(in), optional          :: mode
+       integer, intent(in), optional          :: mode,data
        character, intent(in), optional        :: tran
      end subroutine psb_ihalov
-     subroutine  psb_zhalom(x,desc_a,info,alpha,jx,ik,work,tran,mode)
+     subroutine  psb_zhalom(x,desc_a,info,alpha,jx,ik,work,tran,mode,data)
        use psb_descriptor_type
        complex(kind(1.d0)), intent(inout)           :: x(:,:)
        type(psb_desc_type), intent(in)           :: desc_a
        integer, intent(out)                      :: info
        complex(kind(1.d0)), intent(in), optional    :: alpha
        complex(kind(1.d0)), target, optional        :: work(:)
-       integer, intent(in), optional             :: mode,jx,ik
+       integer, intent(in), optional             :: mode,jx,ik,data
        character, intent(in), optional           :: tran
      end subroutine psb_zhalom
-     subroutine  psb_zhalov(x,desc_a,info,alpha,work,tran,mode)
+     subroutine  psb_zhalov(x,desc_a,info,alpha,work,tran,mode,data)
        use psb_descriptor_type
        complex(kind(1.d0)), intent(inout)           :: x(:)
        type(psb_desc_type), intent(in)           :: desc_a
        integer, intent(out)                      :: info
        complex(kind(1.d0)), intent(in), optional    :: alpha
        complex(kind(1.d0)), target, optional :: work(:)
-       integer, intent(in), optional             :: mode
+       integer, intent(in), optional             :: mode,data
        character, intent(in), optional           :: tran
      end subroutine psb_zhalov
   end interface
diff --git a/base/tools/psb_icdasb.f90 b/base/tools/psb_icdasb.f90
index 3da71b82..d8677c31 100644
--- a/base/tools/psb_icdasb.f90
+++ b/base/tools/psb_icdasb.f90
@@ -135,6 +135,17 @@ subroutine psb_icdasb(desc_a,info,ext_hv)
       call psb_errpush(info,name)
       goto 9999
     end if
+    ! Finally, cleanup the AVL tree, as it is really only needed 
+    ! when building. 
+    if (allocated(desc_a%ptree)) then 
+      call FreePairSearchTree(desc_a%ptree)   
+      deallocate(desc_a%ptree,stat=info)
+      if (info /= 0) then 
+        info=2059
+        call psb_errpush(info,name)
+        goto 9999
+      end if
+    end if
     ! Ok, register into MATRIX_DATA &  free temporary work areas
     desc_a%matrix_data(psb_dec_type_) = psb_desc_asb_
   else