diff --git a/Changelog b/Changelog
index 08e950bb..653fc161 100644
--- a/Changelog
+++ b/Changelog
@@ -2,6 +2,10 @@ Changelog. A lot less detailed than usual, at least for past
 history. 
 
 
+2007/02/01: Merged serial version: we provide a minimal fake mpi to
+	    allow compiling and running without mpi and blacs. Only
+	    tested with gnu42 so far.
+
 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
diff --git a/Make.inc.gcc42 b/Make.inc.gcc42
index 87269cd9..b898b9f8 100644
--- a/Make.inc.gcc42
+++ b/Make.inc.gcc42
@@ -1,6 +1,6 @@
 .mod=.mod
 .fh=.fh
-.SUFFIXES: .f90 $(.mod) .F90
+.SUFFIXES: .f90 $(.mod) .F90 .F
 
 
 #######################  Section 1 #######################
@@ -78,8 +78,12 @@ $(.mod).o:
 	$(F90) $(F90COPT) $(INCDIRS) -c $<
 .f90.o:
 	$(F90) $(F90COPT) $(INCDIRS) -c $<
+.F.o:
+	$(F90) $(F90COPT) $(INCDIRS) $(FDEFINES) -c $<
 .F90.o:
 	$(F90) $(F90COPT) $(INCDIRS) $(FDEFINES) -c $<
+.F90$(.mod):
+	$(F90) $(F90COPT) $(INCDIRS) $(FDEFINES) -c $<
 
 
 
diff --git a/Make.inc.gcc42-serialmpi b/Make.inc.gcc42-serialmpi
new file mode 100644
index 00000000..de886f01
--- /dev/null
+++ b/Make.inc.gcc42-serialmpi
@@ -0,0 +1,92 @@
+.mod=.mod
+.fh=.fh
+.SUFFIXES: .f90 $(.mod) .F90 .F
+
+
+#######################  Section 1 #######################
+#  Define your compilers and compiler flags here         #
+##########################################################
+F90=/usr/local/gcc42/bin/gfortran
+FC=$(F90)
+F77=$(FC)
+CC=/usr/local/gcc42/bin/gcc
+F90COPT=-O3 -ggdb
+FCOPT=-O3 -ggdb
+CCOPT=-O3 -ggdb
+
+#######################  Section 2 #######################
+#  Define your linker and linker flags here              #
+##########################################################
+F90LINK=$(FC)
+FLINK=$(FC)
+MPF90=$(FC)
+MPF77=$(FC)
+MPCC=$(CC)
+
+#######################  Section 3 #######################
+#  Specify paths to libraries                            #
+##########################################################
+BLAS=-lblas-gcc42 -L$(HOME)/LIB
+# No BLACS in serialMPI. But we need the fakempi.o
+#BLACS=-lmpiblacs-gcc42 -L$(HOME)/LIB
+EXTRA_COBJS=fakempi.o
+
+
+#######################  Section 4 #######################
+#  Other useful tools&defines                            #
+##########################################################
+SLUDIR=/usr/local/SuperLU_3.0
+SLU=-lslu_lx_gcc42 -L$(SLUDIR)
+SLUDEF=-DHave_SLU_ -I$(SLUDIR)
+
+UMFDIR=$(HOME)/LIB/Umfpack_gcc41
+UMF=-lumfpack -lamd -L$(UMFDIR)
+UMFDEF=-DHave_UMF_ -I$(UMFDIR)
+#
+#  We are using the public domain tool METIS from U. Minnesota. To get it
+#  check URL http://www.cs.umn.edu:~karypis
+#  
+METIS_LIB = -L$(HOME)/NUMERICAL/metis-4.0 -lmetis 
+LDLIBS=$(BLACS) $(SLU) $(UMF) $(BLAS) $(METIS_LIB)
+
+#  Add -DLargeFptr for 64-bit addresses
+CDEFINES=-DAdd_ $(SLUDEF) $(UMFDEF)
+FDEFINES=-DHAVE_MOVE_ALLOC -DSERIAL_MPI
+
+AR=ar -cur
+RANLIB=ranlib
+
+
+
+#######################  Section 5 #######################
+#  Do not edit this                                      #
+##########################################################
+LIBDIR=lib
+BASELIBNAME=libpsb_base.a
+PRECLIBNAME=libpsb_prec.a
+METHDLIBNAME=libpsb_krylov.a
+UTILLIBNAME=libpsb_util.a
+
+# Under Linux/gmake there is a rule interpreting .mod as Modula source! 
+$(.mod).o:
+	
+.f.o:
+	$(FC) $(FCOPT) $(INCDIRS)  -c $<
+.c.o:
+	$(CC) $(CCOPT) $(INCDIRS) $(CDEFINES) -c $<
+.f$(.mod):
+	$(F90) $(FCOPT) $(INCDIRS) -c $<
+.f90$(.mod):
+	$(F90) $(F90COPT) $(INCDIRS) -c $<
+.f90.o:
+	$(F90) $(F90COPT) $(INCDIRS) -c $<
+.F.o:
+	$(F90) $(F90COPT) $(INCDIRS) $(FDEFINES) -c $<
+.F90.o:
+	$(F90) $(F90COPT) $(INCDIRS) $(FDEFINES) -c $<
+.F90$(.mod):
+	$(F90) $(F90COPT) $(INCDIRS) $(FDEFINES) -c $<
+
+
+
+
diff --git a/Make.inc.ifc9 b/Make.inc.ifc9
index 7f319174..a786eddc 100644
--- a/Make.inc.ifc9
+++ b/Make.inc.ifc9
@@ -1,6 +1,6 @@
 .mod=.mod
 .fh=.fh
-.SUFFIXES: .f90 $(.mod) .F90
+.SUFFIXES: .f90 $(.mod) .F90 .F
 
 
 #######################  Section 1 #######################
@@ -80,8 +80,12 @@ $(.mod).o:
 	$(F90) $(F90COPT) $(INCDIRS) -c $<
 .f90.o:
 	$(F90) $(F90COPT) $(INCDIRS) -c $<
+.F.o:
+	$(F90) $(F90COPT) $(INCDIRS) $(FDEFINES) -c $<
 .F90.o:
 	$(F90) $(F90COPT) $(INCDIRS) $(FDEFINES) -c $<
+.F90$(.mod):
+	$(F90) $(F90COPT) $(INCDIRS) $(FDEFINES) -c $<
 
 
 
diff --git a/Make.inc.rs6k b/Make.inc.rs6k
index b7b8d832..cbd82dad 100644
--- a/Make.inc.rs6k
+++ b/Make.inc.rs6k
@@ -1,13 +1,13 @@
 .mod=.mod
 .fh=.fh
-.SUFFIXES: .f90 $(.mod) .F90 
+.SUFFIXES: .f90 $(.mod) .F90 .F
 
 
 #######################  Section 1 #######################
 #  Define your compilers and compiler flags here         #
 ##########################################################
 F90=xlf95 -qsuffix=f=f90:cpp=F90
-FC=xlf
+FC=xlf  -qsuffix=cpp=F
 F77=$(FC)
 CC=xlc
 F90COPT= -O3 
@@ -78,8 +78,12 @@ $(.mod).o:
 	$(F90) $(F90COPT) $(INCDIRS) -c $<
 .f90.o:
 	$(F90) $(F90COPT) $(INCDIRS) -c $<
+.F.o:
+	$(F90) $(F90COPT) $(INCDIRS) $(FDEFINES) -c $<
 .F90.o:
 	$(F90) $(F90COPT) $(INCDIRS) $(FDEFINES) -c $<
+.F90$(.mod):
+	$(F90) $(F90COPT) $(INCDIRS) $(FDEFINES) -c $<
 
 
 
diff --git a/Makefile b/Makefile
index 0e046563..b4f2cafe 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 include Make.inc
-#PREC=../mld2p4
-PREC=baseprec
+PREC=../mld2p4
+#PREC=baseprec
 
 library:
 	( [ -d lib ] || mkdir lib)
diff --git a/base/comm/psb_iscatter.f90 b/base/comm/psb_iscatter.f90
index c06dce65..c17a096a 100644
--- a/base/comm/psb_iscatter.f90
+++ b/base/comm/psb_iscatter.f90
@@ -121,7 +121,6 @@ subroutine  psb_iscatterm(globx, locx, desc_a, info, iroot)
   n = psb_cd_get_global_cols(desc_a)
   
   call psb_bcast(ictxt,k,root=iiroot)
-
   !  there should be a global check on k here!!!
 
   call psb_chkglobvect(m,n,size(globx),iglobx,jglobx,desc_a,info)
diff --git a/base/internals/Makefile b/base/internals/Makefile
index b6d1b06b..7dff70db 100644
--- a/base/internals/Makefile
+++ b/base/internals/Makefile
@@ -11,8 +11,7 @@ COBJS = avltree.o srcht.o
 
 MPFOBJS = psi_dswapdata.o psi_dswaptran.o psi_iswapdata.o \
 	psi_iswaptran.o psi_desc_index.o \
- 	psi_zswapdata.o psi_zswaptran.o 
-MPFOBJS2 = psi_extrct_dl.o
+ 	psi_zswapdata.o psi_zswaptran.o  psi_extrct_dl.o
 LIBDIR = ..
 MODDIR = ../modules
 INCDIRS = -I $(LIBDIR) -I $(MODDIR) -I . 
@@ -25,7 +24,6 @@ lib: mpfobjs $(FOBJS) $(FOBJS2) $(COBJS) $(MPFOBJS2)
 
 mpfobjs: psi_gthsct.o
 	(make $(MPFOBJS) F90="$(MPF90)" FC="$(MPF90)" FCOPT="$(F90COPT)")	
-	(make $(MPFOBJS2) F90="$(MPF77)" FC="$(MPF77)" FCOPT="$(FCOPT)")
 	(make $(FOBJS2) F90="$(MPF77)" FC="$(MPF77)" FCOPT="$(FCOPT)")
 clean:
 	/bin/rm -f $(MPFOBJS) $(FOBJS) $(COBJS) $(FOBJS2) $(MPFOBJS2)
diff --git a/base/internals/psi_extrct_dl.f b/base/internals/psi_extrct_dl.f
deleted file mode 100644
index 8a77acfe..00000000
--- a/base/internals/psi_extrct_dl.f
+++ /dev/null
@@ -1,282 +0,0 @@
-C
-C             Parallel Sparse BLAS  v2.0
-C   (C) Copyright 2006 Salvatore Filippone    University of Rome Tor Vergata
-C                      Alfredo Buttari        University of Rome Tor Vergata
-C
-C Redistribution and use in source and binary forms, with or without
-C modification, are permitted provided that the following conditions
-C are met:
-C   1. Redistributions of source code must retain the above copyright
-C      notice, this list of conditions and the following disclaimer.
-C   2. Redistributions in binary form must reproduce the above copyright
-C      notice, this list of conditions, and the following disclaimer in the
-C      documentation and/or other materials provided with the distribution.
-C   3. The name of the PSBLAS group or the names of its contributors may
-C      not be used to endorse or promote products derived from this
-C      software without specific written permission.
-C
-C THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-C ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
-C TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-C PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PSBLAS GROUP OR ITS CONTRIBUTORS
-C BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-C CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-C SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-C INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-C CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-C ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-C POSSIBILITY OF SUCH DAMAGE.
-C
-C 
-      subroutine psi_extract_dep_list(desc_data,
-     +  desc_str,dep_list,
-     +  length_dl,np,dl_lda,mode,info)
-
-c    internal routine
-c    ================ 
-c   
-c    _____called by psi_crea_halo and psi_crea_ovrlap ______
-c
-c purpose
-c =======
-c   process root (pid=0) extracts for each process "k" the ordered list of process
-c   to which "k" must communicate. this list with its order is extracted from
-c   desc_str list
-c
-c   
-c  input
-c =======
-c  desc_data :integer array
-c  explanation:
-c  name		 explanation
-c  ------------------ -------------------------------------------------------
-c  desc_data	 array of integer that contains some local and global
-c		 information of matrix.
-c
-c
-c  now we explain each of the above vectors.
-c
-c  let a be a generic sparse matrix. we denote with matdata_a the matrix_data
-c  array for matrix a.
-c  data stored in matrix_data array are:
-c
-c  notation        stored in		     explanation
-c  --------------- ---------------------- -------------------------------------
-c  dec_type        matdata_a[psb_dec_type_]   decomposition type
-c  m 	           matdata_a[m_]          total number of equations
-c  n 	           matdata_a[n_]          total number of variables
-c  n_row           matdata_a[psb_n_row_]      number of local equations
-c  n_col           matdata_a[psb_n_col_]      number of local variables
-c  psb_ctxt_a          matdata_a[ctxt_]       the blacs context handle, indicating
-c	     	                          the global context of the operation
-c					  on the matrix.
-c					  the context itself is global.
-c  desc_str integer array
-c  explanation:
-c  let desc_str_p be the array desc_str for local process.
-c  this is composed of variable dimension blocks for each process to 
-c  communicate to.
-c  each block contain indexes of local halo elements to exchange with other 
-c  process.
-c  let p be the pointer to the first element of a block in desc_str_p.
-c  this block is stored in desc_str_p as :
-c
-c  notation        stored in		          explanation
-c  --------------- --------------------------- -----------------------------------
-c  process_id      desc_str_p[p+psb_proc_id_]      identifier of process which exchange
-c						  data with.
-c  n_elements_recv desc_str_p[p+n_elem_recv_]  number of elements to receive.
-c  elements_recv   desc_str_p[p+elem_recv_+i]  indexes of local elements to
-c					          receive. these are stored in the
-c					          array from location p+elem_recv_ to
-c					          location p+elem_recv_+
-c						  desc_str_p[p+n_elem_recv_]-1.
-c  if desc_data(psb_dec_type_) == 0 
-c  then also will be:
-c  n_elements_send desc_str_p[p+n_elem_send_]  number of elements to send.
-c  elements_send   desc_str_p[p+elem_send_+i]  indexes of local elements to
-c					          send. these are stored in the
-c					          array from location p+elem_send_ to
-c					          location p+elem_send_+
-c						  desc_str_p[p+n_elem_send_]-1.
-c  list is ended by -1 value
-c  
-c  np     integer (global input)
-c         number of grid process.
-c
-c  mode   integer (global input)
-c         if mode =0 then will be inserted also duplicate element in 
-c         a same dependence list
-c         if mode =1 then not will be inserted duplicate element in
-c          a same dependence list
-c  output
-c  =====
-c  only for root (pid=0) process:
-c  dep_list  integer array(dl_lda,0:np)
-c            dependence list dep_list(*,i) is the list of process identifiers to which process i
-c            must communicate with. this list with its order is extracted from
-c            desc_str list.
-c   length_dl  integer array(0:np)
-c             length_dl(i) is the length of dep_list(*,i) list
-      use psb_penv_mod
-      use psb_const_mod
-      use psb_error_mod
-      use psb_descriptor_type
-      implicit none
-      include 'mpif.h'
-c     ....scalar parameters...
-      integer np,dl_lda,mode, info
-
-c     ....array parameters....
-      integer desc_str(*),desc_data(*),
-     +  dep_list(dl_lda,0:np),length_dl(0:np)
-      integer, pointer :: itmp(:)
-c     .....local arrays....
-      integer int_err(5)
-      double precision real_err(5)
-
-c     .....local scalars...
-      integer i,nprow,npcol,me,mycol,pointer_dep_list,proc,j,err_act
-      integer ictxt, err, icomm
-      logical debug
-      parameter (debug=.false.)
-      character  name*20
-      name='psi_extrct_dl'
-      
-      call psb_erractionsave(err_act)
-
-      info = 0
-      ictxt = desc_data(psb_ctxt_)
-
-
-      call psb_info(ictxt,me,nprow)
-      do i=0,np 
-        length_dl(i) = 0
-      enddo
-      i=1
-      if (debug) write(0,*) 'extract: info ',info,
-     +  desc_data(psb_dec_type_)
-      pointer_dep_list=1
-c$$$      if (desc_data(psb_dec_type_).eq.psb_desc_bld_) then
-      if (psb_is_bld_dec(desc_data(psb_dec_type_))) then 
-        do while (desc_str(i).ne.-1)
-          if (debug) write(0,*) me,' extract: looping ',i,
-     +      desc_str(i),desc_str(i+1),desc_str(i+2)
-          
-c        ...with different decomposition type we have different
-c           structure of indices  lists............................
-          if ((desc_str(i+1).ne.0).or.(desc_str(i+2).ne.0)) then
-c           ..if number of element to be exchanged !=0
-            proc=desc_str(i)
-            if ((proc.lt.0).or.(proc.ge.nprow)) then
-              if (debug) write(0,*) 'extract error ',i,desc_str(i)
-              info = 9999
-              int_err(1) = i
-              int_err(2) = desc_str(i)
-              goto 998
-            endif
-!            if((me.eq.1).and.(proc.eq.3))write(0,*)'found 3'
-            if (mode.eq.1) then
-c              ...search if already exist proc 
-c                 in dep_list(*,me)...  
-              j=1
-              do while ((j.lt.pointer_dep_list).and.
-     +          (dep_list(j,me).ne.proc))
-                j=j+1
-              enddo
-              
-              if (j.eq.pointer_dep_list) then
-c                 ...if not found.....
-                dep_list(pointer_dep_list,me)=proc
-                pointer_dep_list=pointer_dep_list+1
-              endif
-            else if (mode.eq.0) then
-              if (pointer_dep_list.gt.dl_lda) then
-                info = 4000
-                goto 998
-              endif
-              dep_list(pointer_dep_list,me)=proc
-              pointer_dep_list=pointer_dep_list+1
-            endif
-          endif
-          i=i+desc_str(i+1)+2
-        enddo
-c$$$      else if (desc_data(psb_dec_type_).eq.psb_desc_upd_) then
-      else if (psb_is_upd_dec(desc_data(psb_dec_type_))) then
-        do while (desc_str(i).ne.-1)
-          if (debug) write(0,*) 'extract: looping ',i,desc_str(i)
-          
-c        ...with different decomposition type we have different
-c           structure of indices  lists............................
-          if (desc_str(i+1).ne.0) then
-            
-            proc=desc_str(i)
-c        ..if number of element to be exchanged !=0
-            
-            if (mode.eq.1) then
-c              ...search if already exist proc....                 
-              j=1
-              do while ((j.lt.pointer_dep_list).and.
-     +          (dep_list(j,me).ne.proc))
-                j=j+1
-              enddo
-              if (j.eq.pointer_dep_list) then
-c                 ...if not found.....
-                if (pointer_dep_list.gt.dl_lda) then
-                  info = 4000
-                  goto 998
-                endif
-                dep_list(pointer_dep_list,me)=proc
-                pointer_dep_list=pointer_dep_list+1
-              endif
-            else if (mode.eq.0) then
-              if (pointer_dep_list.gt.dl_lda) then
-                info = 4000
-                goto 998
-              endif
-              dep_list(pointer_dep_list,me)=proc
-              pointer_dep_list=pointer_dep_list+1
-            endif
-          endif
-          i=i+desc_str(i+1)+2
-        enddo
-      else
-        write(0,*) 'invalid dec_type',desc_data(psb_dec_type_)
-        info = 2020
-        goto 9999
-      endif
-
-      length_dl(me)=pointer_dep_list-1
-
-c     ... check for errors...
- 998  continue 
-      if (debug) write(0,*) 'extract: info ',info
-      err = info
-
-      if (err.ne.0) goto 9999
-
-      call psb_sum(ictxt,length_dl(0:np))
-      call psb_get_mpicomm(ictxt,icomm )
-      allocate(itmp(dl_lda),stat=info)
-      if (info /= 0) goto 9999
-      itmp(1:dl_lda) = dep_list(1:dl_lda,me)
-      call mpi_allgather(itmp,dl_lda,mpi_integer,
-     +  dep_list,dl_lda,mpi_integer,icomm,info)
-      deallocate(itmp)
-
-      call psb_erractionrestore(err_act)
-      return
-
-
- 9999 continue
-
-      call psb_errpush(info,name,i_err=int_err)
-      call psb_erractionrestore(err_act)
-      if (err_act.eq.psb_act_ret_) then
-        return
-      else
-        call psb_error()
-      endif
-      return
-
-      end
diff --git a/base/internals/psi_extrct_dl.f90 b/base/internals/psi_extrct_dl.f90
new file mode 100644
index 00000000..f5fb633a
--- /dev/null
+++ b/base/internals/psi_extrct_dl.f90
@@ -0,0 +1,276 @@
+!!$ 
+!!$              Parallel Sparse BLAS  v2.0
+!!$    (C) Copyright 2006 Salvatore Filippone    University of Rome Tor Vergata
+!!$                       Alfredo Buttari        University of Rome Tor Vergata
+!!$ 
+!!$  Redistribution and use in source and binary forms, with or without
+!!$  modification, are permitted provided that the following conditions
+!!$  are met:
+!!$    1. Redistributions of source code must retain the above copyright
+!!$       notice, this list of conditions and the following disclaimer.
+!!$    2. Redistributions in binary form must reproduce the above copyright
+!!$       notice, this list of conditions, and the following disclaimer in the
+!!$       documentation and/or other materials provided with the distribution.
+!!$    3. The name of the PSBLAS group or the names of its contributors may
+!!$       not be used to endorse or promote products derived from this
+!!$       software without specific written permission.
+!!$ 
+!!$  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+!!$  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+!!$  TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+!!$  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PSBLAS GROUP OR ITS CONTRIBUTORS
+!!$  BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+!!$  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+!!$  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+!!$  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+!!$  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+!!$  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+!!$  POSSIBILITY OF SUCH DAMAGE.
+!!$ 
+!!$  
+subroutine psi_extract_dep_list(desc_data,desc_str,dep_list,&
+     & length_dl,np,dl_lda,mode,info)
+
+  !    internal routine
+  !    ================ 
+  !   
+  !    _____called by psi_crea_halo and psi_crea_ovrlap ______
+  !
+  ! purpose
+  ! =======
+  !   process root (pid=0) extracts for each process "k" the ordered list of process
+  !   to which "k" must communicate. this list with its order is extracted from
+  !   desc_str list
+  ! 
+  !   
+  !  input
+  ! =======
+  !  desc_data :integer array
+  !  explanation:
+  !  name		 explanation
+  !  ------------------ -------------------------------------------------------
+  !  desc_data	 array of integer that contains some local and global
+  !		 information of matrix.
+  !
+  !
+  !  now we explain each of the above vectors.
+  !
+  !  let a be a generic sparse matrix. we denote with matdata_a the matrix_data
+  !  array for matrix a.
+  !  data stored in matrix_data array are:
+  !
+  !  notation        stored in		     explanation
+  !  --------------- ---------------------- -------------------------------------
+  !  dec_type        matdata_a[psb_dec_type_]   decomposition type
+  !  m 	           matdata_a[m_]          total number of equations
+  !  n 	           matdata_a[n_]          total number of variables
+  !  n_row           matdata_a[psb_n_row_]      number of local equations
+  !  n_col           matdata_a[psb_n_col_]      number of local variables
+  !  psb_ctxt_a          matdata_a[ctxt_]       the blacs context handle, indicating
+  !	     	                          the global context of the operation
+  !					  on the matrix.
+  !					  the context itself is global.
+  !  desc_str integer array
+  !  explanation:
+  !  let desc_str_p be the array desc_str for local process.
+  !! this is composed of variable dimension blocks for each process to 
+  !  communicate to.
+  !  each block contain indexes of local halo elements to exchange with other 
+  !  process.
+  !  let p be the pointer to the first element of a block in desc_str_p.
+  !  this block is stored in desc_str_p as :
+  !
+  !  notation        stored in		          explanation
+  !  --------------- --------------------------- -----------------------------------
+  !  process_id      desc_str_p[p+psb_proc_id_]      identifier of process which exchange
+  !						  data with.
+  !  n_elements_recv desc_str_p[p+n_elem_recv_]  number of elements to receive.
+  !  elements_recv   desc_str_p[p+elem_recv_+i]  indexes of local elements to
+  !					          receive. these are stored in the
+  !					          array from location p+elem_recv_ to
+  !					          location p+elem_recv_+
+  !						  desc_str_p[p+n_elem_recv_]-1.
+  !  if desc_data(psb_dec_type_) == 0 
+  !  then also will be:
+  !  n_elements_send desc_str_p[p+n_elem_send_]  number of elements to send.
+  !  elements_send   desc_str_p[p+elem_send_+i]  indexes of local elements to
+  !					          send. these are stored in the
+  !					          array from location p+elem_send_ to
+  !					          location p+elem_send_+
+  !						  desc_str_p[p+n_elem_send_]-1.
+  !  list is ended by -1 value
+  !  
+  !  np     integer (global input)
+  !         number of grid process.
+  !
+  !  mode   integer (global input)
+  !         if mode =0 then will be inserted also duplicate element in 
+  !         a same dependence list
+  !         if mode =1 then not will be inserted duplicate element in
+  !          a same dependence list
+  !  output
+  !  =====
+  !  only for root (pid=0) process:
+  !  dep_list  integer array(dl_lda,0:np)
+  !            dependence list dep_list(*,i) is the list of process identifiers to which process i
+  !            must communicate with. this list with its order is extracted from
+  !            desc_str list.
+  !   length_dl  integer array(0:np)
+  !             length_dl(i) is the length of dep_list(*,i) list
+  use mpi
+  use psb_penv_mod
+  use psb_const_mod
+  use psb_error_mod
+  use psb_descriptor_type
+  implicit none
+  !     ....scalar parameters...
+  integer np,dl_lda,mode, info
+
+  !     ....array parameters....
+  integer ::  desc_str(*),desc_data(*),dep_list(dl_lda,0:np),length_dl(0:np)
+  integer, pointer :: itmp(:)
+  !     .....local arrays....
+  integer int_err(5)
+  double precision real_err(5)
+
+  !     .....local scalars...
+  integer i,nprow,npcol,me,mycol,pointer_dep_list,proc,j,err_act
+  integer ictxt, err, icomm
+  logical, parameter :: debug=.false.
+  character  name*20
+  name='psi_extrct_dl'
+
+  call psb_erractionsave(err_act)
+
+  info = 0
+  ictxt = desc_data(psb_ctxt_)
+
+
+  call psb_info(ictxt,me,nprow)
+  do i=0,np 
+    length_dl(i) = 0
+  enddo
+  i=1
+  if (debug) write(0,*) 'extract: info ',info,desc_data(psb_dec_type_)
+  pointer_dep_list=1
+  if (psb_is_bld_dec(desc_data(psb_dec_type_))) then 
+    do while (desc_str(i) /= -1)
+      if (debug) write(0,*) me,' extract: looping ',i,&
+           &    desc_str(i),desc_str(i+1),desc_str(i+2)
+
+      !        ...with different decomposition type we have different
+      !           structure of indices  lists............................
+      if ((desc_str(i+1) /= 0).or.(desc_str(i+2) /= 0)) then
+        !           ..if number of element to be exchanged !=0
+        proc=desc_str(i)
+        if ((proc < 0).or.(proc.ge.nprow)) then
+          if (debug) write(0,*) 'extract error ',i,desc_str(i)
+          info = 9999
+          int_err(1) = i
+          int_err(2) = desc_str(i)
+          goto 998
+        endif
+        !            if((me == 1).and.(proc == 3))write(0,*)'found 3'
+        if (mode == 1) then
+          !              ...search if already exist proc 
+          !                 in dep_list(*,me)...  
+          j=1
+          do while ((j < pointer_dep_list).and.&
+               & (dep_list(j,me) /= proc))
+            j=j+1
+          enddo
+
+          if (j == pointer_dep_list) then
+            !                 ...if not found.....
+            dep_list(pointer_dep_list,me)=proc
+            pointer_dep_list=pointer_dep_list+1
+          endif
+        else if (mode == 0) then
+          if (pointer_dep_list.gt.dl_lda) then
+            info = 4000
+            goto 998
+          endif
+          dep_list(pointer_dep_list,me)=proc
+          pointer_dep_list=pointer_dep_list+1
+        endif
+      endif
+      i=i+desc_str(i+1)+2
+    enddo
+  else if (psb_is_upd_dec(desc_data(psb_dec_type_))) then
+    do while (desc_str(i) /= -1)
+      if (debug) write(0,*) 'extract: looping ',i,desc_str(i)
+
+      !        ...with different decomposition type we have different
+      !           structure of indices  lists............................
+      if (desc_str(i+1) /= 0) then
+
+        proc=desc_str(i)
+        !        ..if number of element to be exchanged !=0
+
+        if (mode == 1) then
+          !              ...search if already exist proc....                 
+          j=1
+          do while ((j < pointer_dep_list).and.&
+               & (dep_list(j,me) /= proc))
+            j=j+1
+          enddo
+          if (j == pointer_dep_list) then
+            !                 ...if not found.....
+            if (pointer_dep_list.gt.dl_lda) then
+              info = 4000
+              goto 998
+            endif
+            dep_list(pointer_dep_list,me)=proc
+            pointer_dep_list=pointer_dep_list+1
+          endif
+        else if (mode == 0) then
+          if (pointer_dep_list.gt.dl_lda) then
+            info = 4000
+            goto 998
+          endif
+          dep_list(pointer_dep_list,me)=proc
+          pointer_dep_list=pointer_dep_list+1
+        endif
+      endif
+      i=i+desc_str(i+1)+2
+    enddo
+  else
+    write(0,*) 'invalid dec_type',desc_data(psb_dec_type_)
+    info = 2020
+    goto 9999
+  endif
+
+  length_dl(me)=pointer_dep_list-1
+
+  !     ... check for errors...
+998 continue 
+  if (debug) write(0,*) 'extract: info ',info
+  err = info
+
+  if (err /= 0) goto 9999
+
+  call psb_sum(ictxt,length_dl(0:np))
+  call psb_get_mpicomm(ictxt,icomm )
+  allocate(itmp(dl_lda),stat=info)
+  if (info /= 0) goto 9999
+  itmp(1:dl_lda) = dep_list(1:dl_lda,me)
+  call mpi_allgather(itmp,dl_lda,mpi_integer,&
+       & dep_list,dl_lda,mpi_integer,icomm,info)
+  deallocate(itmp)
+
+  call psb_erractionrestore(err_act)
+  return
+
+
+9999 continue
+
+  call psb_errpush(info,name,i_err=int_err)
+  call psb_erractionrestore(err_act)
+  if (err_act == psb_act_ret_) then
+    return
+  else
+    call psb_error()
+  endif
+  return
+
+end subroutine psi_extract_dep_list
diff --git a/base/modules/Makefile b/base/modules/Makefile
index fb3135b3..2cbf591c 100644
--- a/base/modules/Makefile
+++ b/base/modules/Makefile
@@ -12,7 +12,7 @@ MODULES = psb_realloc_mod.o psb_string_mod.o psb_spmat_type.o \
 
 LIBMOD=psb_base_mod$(.mod)
 MPFOBJS=psb_penv_mod.o 
-OBJS = error.o psb_base_mod.o 
+OBJS = error.o psb_base_mod.o $(EXTRA_COBJS)
 LIBDIR = ..
 INCDIRS = -I . 
 
diff --git a/base/modules/blacs_env.F90 b/base/modules/blacs_env.F90
index 824d50ae..8aae4ad2 100644
--- a/base/modules/blacs_env.F90
+++ b/base/modules/blacs_env.F90
@@ -23,15 +23,23 @@ subroutine psb_restore_coher(ictxt,isvch)
 end subroutine psb_restore_coher
 subroutine psb_get_mpicomm(ictxt,comm)
   integer :: ictxt, comm
+#if !defined(SERIAL_MPI)
   call blacs_get(ictxt,10,comm)
+#else    
+  comm = ictxt
+#endif
 end subroutine psb_get_mpicomm
 subroutine psb_get_rank(rank,ictxt,id)
   integer :: rank,ictxt, id
   integer :: blacs_pnum
+#if defined(SERIAL_MPI)
+  rank = 0
+#else
   rank =  blacs_pnum(ictxt,id,0)
+#endif    
 end subroutine psb_get_rank
 
-#ifdef ESSL_BLACS
+#if defined(ESSL_BLACS) || defined(SERIAL_MPI)
 !
 ! Need these, as they are not in the ESSL implementation 
 ! of the BLACS. 
diff --git a/base/modules/error.f90 b/base/modules/error.f90
index 70782b36..3dc53fbe 100644
--- a/base/modules/error.f90
+++ b/base/modules/error.f90
@@ -101,7 +101,7 @@ subroutine FCpsb_get_errverbosity(v)
 
   integer, intent(out)   :: v
 
-  call psb_get_errverbosity(v)
+  v = psb_get_errverbosity()
 
 end subroutine FCpsb_get_errverbosity
 
diff --git a/base/modules/fakempi.c b/base/modules/fakempi.c
new file mode 100644
index 00000000..c1fba4b0
--- /dev/null
+++ b/base/modules/fakempi.c
@@ -0,0 +1,134 @@
+#include <sys/time.h>
+#include <stdio.h>
+#include <string.h>
+
+#ifdef Add_
+#define mpi_wtime       mpi_wtime_
+#define mpi_send        mpi_send_
+#define mpi_irecv       mpi_irecv_
+#define mpi_wait        mpi_wait_
+#define mpi_alltoall    mpi_alltoall_
+#define mpi_alltoallv   mpi_alltoallv_
+#define mpi_allgather   mpi_allgather_
+#define mpi_allgatherv  mpi_allgatherv_
+#endif
+#define mpi_integer        1
+#define mpi_double         3
+#define mpi_double_complex 5
+
+double mpi_wtime() 
+{
+  struct timeval tt;
+  struct timezone tz;
+  double temp;
+  if (gettimeofday(&tt,&tz) != 0) {
+    fprintf(stderr,"Fatal error for gettimeofday ??? \n");
+    temp=0.0;
+  } else {
+    temp = ((double)tt.tv_sec) + ((double)tt.tv_usec)*1.0e-6;
+  }
+  return(temp);
+}
+
+
+void mpi_wait()
+{
+  return;
+}
+void mpi_send()
+{
+  return;
+}
+void mpi_irecv()
+{
+  return;
+}
+
+
+void mpi_alltoall(void* sdb, int* sdc, int* sdt,
+		  void* rvb, int* rvc, int* rvt, int* comm, int* ierr)
+{
+  int i,j,k; 
+  
+  if (*sdt == mpi_integer) {
+    memcpy(rvb,sdb, (*sdc)*sizeof(int));
+  }
+  if (*sdt == mpi_double) {
+    memcpy(rvb,sdb, (*sdc)*sizeof(double));
+  } 
+  if (*sdt == mpi_double_complex) {
+    memcpy(rvb,sdb, (*sdc)*2*sizeof(double));
+  }
+  *ierr = 0;
+}
+
+void mpi_alltoallv(void* sdb, int* sdc, int* sdspl, int* sdt,
+		   void* rvb, int* rvc, int* rdspl, int* rvt, int* comm, int* ierr)
+{
+  int i,j,k; 
+
+  
+  if (*sdt == mpi_integer) {
+    memcpy((rvb+rdspl[0]*sizeof(int)),
+	   (sdb+sdspl[0]*sizeof(int)),(*sdc)*sizeof(int));
+  }
+  if (*sdt == mpi_double) {
+    memcpy((rvb+rdspl[0]*sizeof(double)),
+	   (sdb+sdspl[0]*sizeof(double)),(*sdc)*sizeof(double));
+  } 
+  if (*sdt == mpi_double_complex) {
+    memcpy((rvb+rdspl[0]*2*sizeof(double)),
+	   (sdb+sdspl[0]*2*sizeof(double)),(*sdc)*2*sizeof(double));
+  }
+  *ierr = 0;
+}
+
+
+void mpi_allgather(void* sdb, int* sdc, int* sdt,
+		   void* rvb, int* rvc, int* rvt, int* comm, int* ierr)
+{
+  int i,j,k; 
+  
+  if (*sdt == mpi_integer) {
+    memcpy(rvb,sdb, (*sdc)*sizeof(int));
+  }
+  if (*sdt == mpi_double) {
+    memcpy(rvb,sdb, (*sdc)*sizeof(double));
+  } 
+  if (*sdt == mpi_double_complex) {
+    memcpy(rvb,sdb, (*sdc)*2*sizeof(double));
+  }
+  *ierr = 0;
+}
+
+void mpi_allgatherv(void* sdb, int* sdc, int* sdt,
+		    void* rvb, int* rvc, int* rdspl,
+		    int* rvt, int* comm, int* ierr)
+{
+  int i,j,k; 
+  
+  if (*sdt == mpi_integer) {
+    memcpy(rvb,sdb, (*sdc)*sizeof(int));
+  }
+  if (*sdt == mpi_double) {
+    memcpy(rvb,sdb, (*sdc)*sizeof(double));
+  } 
+  if (*sdt == mpi_double_complex) {
+    memcpy(rvb,sdb, (*sdc)*2*sizeof(double));
+  }
+  if (*sdt == mpi_integer) {
+    memcpy((rvb+rdspl[0]*sizeof(int)),
+	   (sdb),(*sdc)*sizeof(int));
+  }
+  if (*sdt == mpi_double) {
+    memcpy((rvb+rdspl[0]*sizeof(double)),
+	   (sdb),(*sdc)*sizeof(double));
+  } 
+  if (*sdt == mpi_double_complex) {
+    memcpy((rvb+rdspl[0]*2*sizeof(double)),
+	   (sdb),(*sdc)*2*sizeof(double));
+  }
+
+
+  *ierr = 0;
+}
diff --git a/base/modules/psb_error_mod.f90 b/base/modules/psb_error_mod.F90
similarity index 98%
rename from base/modules/psb_error_mod.f90
rename to base/modules/psb_error_mod.F90
index d893bd5b..376ca201 100644
--- a/base/modules/psb_error_mod.f90
+++ b/base/modules/psb_error_mod.F90
@@ -112,8 +112,10 @@ contains
     integer :: temp(2)
     integer, parameter :: ione=1
     ! Cannot use psb_amx or otherwise we have a recursion in module usage
+#if !defined(SERIAL_MPI)
     call igamx2d(ictxt, 'A', ' ', ione, ione, err, ione,&
          &temp ,temp,-ione ,-ione,-ione)
+#endif    
   end subroutine psb_errcomm
 
 
@@ -127,10 +129,11 @@ contains
 
 
   ! returns verbosity of the error message
-  subroutine psb_get_errverbosity(v)
-    integer, intent(out) :: v
-    v=verbosity_level
-  end subroutine psb_get_errverbosity
+  function psb_get_errverbosity()
+    integer :: psb_get_errverbosity
+
+    psb_get_errverbosity=verbosity_level
+  end function psb_get_errverbosity
 
 
 
@@ -203,7 +206,6 @@ contains
     integer                 ::  nprow, npcol, me, mypcol
     integer, parameter      ::  ione=1, izero=0
 
-    call blacs_gridinfo(ictxt, nprow, npcol, me, mypcol)
 
     if(error_status.gt.0) then
       if(verbosity_level.gt.1) then
@@ -214,7 +216,11 @@ contains
           call psb_errmsg(err_c, r_name, i_e_d, a_e_d,me)
           !            write(0,'(50("="))')
         end do
+#if defined(SERIAL_MPI)
+        stop 
+#else        
         call blacs_abort(ictxt,-1)
+#endif
       else
 
         call psb_errpop(err_c, r_name, i_e_d, a_e_d)
@@ -222,12 +228,20 @@ contains
         do while (error_stack%n_elems.gt.0)
           call psb_errpop(err_c, r_name, i_e_d, a_e_d)
         end do
+#if defined(SERIAL_MPI)
+        stop 
+#else        
         call blacs_abort(ictxt,-1)
+#endif
       end if
     end if
 
     if(error_status.gt.izero) then
+#if defined(SERIAL_MPI)
+        stop 
+#else        
       call blacs_abort(ictxt,err_c)
+#endif
     end if
 
 
diff --git a/base/modules/psb_penv_mod.f90 b/base/modules/psb_penv_mod.F90
similarity index 92%
rename from base/modules/psb_penv_mod.f90
rename to base/modules/psb_penv_mod.F90
index b8e57c58..3ad735ee 100644
--- a/base/modules/psb_penv_mod.f90
+++ b/base/modules/psb_penv_mod.F90
@@ -28,6 +28,18 @@
 !!$  POSSIBILITY OF SUCH DAMAGE.
 !!$ 
 !!$  
+#if defined(SERIAL_MPI)
+! Provide a fake mpi module just to keep the compiler(s) happy.
+module mpi
+  integer, parameter :: mpi_success=0
+  integer, parameter :: mpi_request_null=0
+  integer, parameter :: mpi_status_size=1
+  integer, parameter :: mpi_integer=1, mpi_double_precision=3
+  integer, parameter :: mpi_double_complex=5 
+  real(kind(1.d0)), external :: mpi_wtime
+end module mpi
+#endif    
+
 module psb_penv_mod
 
 
@@ -107,6 +119,7 @@ module psb_penv_mod
          & psb_zsums, psb_zsumv, psb_zsumm
   end interface
 
+#if !defined(SERIAL_MPI)
   
   interface gebs2d
     module procedure igebs2ds, igebs2dv, igebs2dm,&
@@ -150,12 +163,13 @@ module psb_penv_mod
          &           dgamn2ds, dgamn2dv, dgamn2dm,&
          &           zgamn2ds, zgamn2dv, zgamn2dm
   end interface
+#endif    
 
-
-contains 
-
-
+#if defined(SERIAL_MPI)
+  integer, private, save :: nctxt=0
+#endif
   
+contains 
 
   subroutine psb_init(ictxt,np)
     use psb_const_mod
@@ -165,7 +179,11 @@ contains
     
     integer :: np_, npavail, iam, info
     character(len=20), parameter :: name='psb_init'
-    
+#if defined(SERIAL_MPI) 
+    ictxt = nctxt
+    nctxt = nctxt + 1
+    np_   = 1
+#else    
     call blacs_pinfo(iam, npavail)
     call blacs_get(izero, izero, ictxt)
     
@@ -176,7 +194,7 @@ contains
     endif
     
     call blacs_gridinit(ictxt, 'R', np_, ione)
-    
+#endif    
     if (present(np)) then 
       if (np_ < np) then 
         info = 2011
@@ -192,7 +210,8 @@ contains
     logical, intent(in), optional :: close
     logical  :: close_
     integer  :: nprow, npcol, myprow, mypcol
-    
+
+#if !defined(SERIAL_MPI)
     if (present(close)) then 
       close_ = close
     else
@@ -203,28 +222,34 @@ contains
       call blacs_gridexit(ictxt)
     end if
     if (close_) call blacs_exit(0)
+#endif
   end subroutine psb_exit
 
 
   subroutine psb_barrier(ictxt)
     integer, intent(in) :: ictxt
-    
+
+#if !defined(SERIAL_MPI)
     call blacs_barrier(ictxt,'All')
+#endif    
     
   end subroutine psb_barrier
 
   function psb_wtime()
+    use mpi
     real(kind(1.d0)) :: psb_wtime
-    
-    real(kind(1.d0)), external :: mpi_wtime
-    
+
     psb_wtime = mpi_wtime()
   end function psb_wtime
 
   subroutine psb_abort(ictxt)
     integer, intent(in) :: ictxt
     
+#if defined(SERIAL_MPI) 
+    stop
+#else    
     call blacs_abort(ictxt,-1)
+#endif    
     
   end subroutine psb_abort
 
@@ -235,10 +260,15 @@ contains
     integer, intent(out) :: iam, np
     integer              :: nprow, npcol, myprow, mypcol
     
+#if defined(SERIAL_MPI) 
+    iam = 0
+    np  = 1
+#else    
     call blacs_gridinfo(ictxt, nprow, npcol, myprow, mypcol)
     
     iam = myprow
     np  = nprow
+#endif    
     
   end subroutine psb_info
 
@@ -250,6 +280,7 @@ contains
 
     integer  :: iam, np, root_
 
+#if !defined(SERIAL_MPI)
     if (present(root)) then
       root_ = root
     else
@@ -263,6 +294,7 @@ contains
     else
       call gebr2d(ictxt,'A',dat,rrt=root_)
     endif
+#endif    
   end subroutine psb_ibcasts
 
   subroutine psb_ibcastv(ictxt,dat,root)
@@ -272,6 +304,7 @@ contains
 
     integer  :: iam, np, root_
 
+#if !defined(SERIAL_MPI)
     if (present(root)) then
       root_ = root
     else
@@ -285,6 +318,7 @@ contains
     else
       call gebr2d(ictxt,'A',dat,rrt=root_)
     endif
+#endif    
   end subroutine psb_ibcastv
     
   subroutine psb_ibcastm(ictxt,dat,root)
@@ -294,6 +328,7 @@ contains
 
     integer  :: iam, np, root_
 
+#if !defined(SERIAL_MPI)
     if (present(root)) then
       root_ = root
     else
@@ -307,6 +342,7 @@ contains
     else
       call gebr2d(ictxt,'A',dat,rrt=root_)
     endif
+#endif    
   end subroutine psb_ibcastm
 
 
@@ -317,6 +353,7 @@ contains
 
     integer  :: iam, np, root_
 
+#if !defined(SERIAL_MPI)
     if (present(root)) then
       root_ = root
     else
@@ -330,6 +367,7 @@ contains
     else
       call gebr2d(ictxt,'A',dat,rrt=root_)
     endif
+#endif    
   end subroutine psb_dbcasts
 
 
@@ -340,6 +378,7 @@ contains
 
     integer  :: iam, np, root_
 
+#if !defined(SERIAL_MPI)
     if (present(root)) then
       root_ = root
     else
@@ -353,6 +392,7 @@ contains
     else
       call gebr2d(ictxt,'A',dat,rrt=root_)
     endif
+#endif    
   end subroutine psb_dbcastv
     
   subroutine psb_dbcastm(ictxt,dat,root)
@@ -362,6 +402,7 @@ contains
 
     integer  :: iam, np, root_
 
+#if !defined(SERIAL_MPI)
     if (present(root)) then
       root_ = root
     else
@@ -375,6 +416,7 @@ contains
     else
       call gebr2d(ictxt,'A',dat,rrt=root_)
     endif
+#endif    
   end subroutine psb_dbcastm
     
 
@@ -385,6 +427,7 @@ contains
 
     integer  :: iam, np, root_
 
+#if !defined(SERIAL_MPI)
     if (present(root)) then
       root_ = root
     else
@@ -398,6 +441,7 @@ contains
     else
       call gebr2d(ictxt,'A',dat,rrt=root_)
     endif
+#endif    
   end subroutine psb_zbcasts
 
   subroutine psb_zbcastv(ictxt,dat,root)
@@ -407,6 +451,7 @@ contains
 
     integer  :: iam, np, root_
 
+#if !defined(SERIAL_MPI)
     if (present(root)) then
       root_ = root
     else
@@ -420,6 +465,7 @@ contains
     else
       call gebr2d(ictxt,'A',dat,rrt=root_)
     endif
+#endif    
   end subroutine psb_zbcastv
     
   subroutine psb_zbcastm(ictxt,dat,root)
@@ -429,6 +475,7 @@ contains
 
     integer  :: iam, np, root_
 
+#if !defined(SERIAL_MPI)
     if (present(root)) then
       root_ = root
     else
@@ -442,6 +489,7 @@ contains
     else
       call gebr2d(ictxt,'A',dat,rrt=root_)
     endif
+#endif    
   end subroutine psb_zbcastm
 
 
@@ -453,6 +501,7 @@ contains
 
     integer  :: iam, np, root_,icomm,length_,info
 
+#if !defined(SERIAL_MPI)
     if (present(root)) then
       root_ = root
     else
@@ -468,6 +517,7 @@ contains
     call psb_get_mpicomm(ictxt,icomm)
     
     call mpi_bcast(dat,length_,MPI_CHARACTER,root_,icomm,info)
+#endif    
 
   end subroutine psb_hbcasts
 
@@ -479,6 +529,7 @@ contains
 
     integer  :: iam, np, root_,icomm,info
 
+#if !defined(SERIAL_MPI)
     if (present(root)) then
       root_ = root
     else
@@ -488,6 +539,7 @@ contains
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
     call mpi_bcast(dat,1,MPI_LOGICAL,root_,icomm,info)
+#endif    
 
   end subroutine psb_lbcasts
 
@@ -502,6 +554,7 @@ contains
     integer :: iam, np, icomm
     
 
+#if !defined(SERIAL_MPI)
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
 
@@ -517,6 +570,7 @@ contains
       call mpi_reduce(dat,dat_,1,mpi_integer,mpi_max,root_,icomm)
       dat = dat_
     endif
+#endif    
   end subroutine psb_imaxs
   subroutine psb_imaxv(ictxt,dat,root)
     use mpi
@@ -528,6 +582,7 @@ contains
     integer, allocatable :: dat_(:)
     integer :: iam, np, icomm, info
     
+#if !defined(SERIAL_MPI)
 
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
@@ -548,6 +603,7 @@ contains
         call mpi_reduce(dat,dat_,size(dat),mpi_integer,mpi_max,root_,icomm)
       end if
     endif
+#endif    
   end subroutine psb_imaxv
   subroutine psb_imaxm(ictxt,dat,root)
     use mpi
@@ -560,6 +616,7 @@ contains
     integer :: iam, np, icomm, info
     
 
+#if !defined(SERIAL_MPI)
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
 
@@ -579,6 +636,7 @@ contains
         call mpi_reduce(dat,dat_,size(dat),mpi_integer,mpi_max,root_,icomm)
       end if
     endif
+#endif    
   end subroutine psb_imaxm
   
   subroutine psb_dmaxs(ictxt,dat,root)
@@ -591,6 +649,7 @@ contains
     integer :: iam, np, icomm
     
 
+#if !defined(SERIAL_MPI)
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
 
@@ -606,6 +665,7 @@ contains
       call mpi_reduce(dat,dat_,1,mpi_double_precision,mpi_max,root_,icomm)
       dat = dat_
     endif
+#endif    
   end subroutine psb_dmaxs
   subroutine psb_dmaxv(ictxt,dat,root)
     use mpi
@@ -618,6 +678,7 @@ contains
     integer :: iam, np, icomm, info
     
 
+#if !defined(SERIAL_MPI)
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
 
@@ -629,7 +690,8 @@ contains
     if (root_ == -1) then 
       call psb_realloc(size(dat),dat_,info)
       dat_ = dat
-      if (info ==0) call mpi_allreduce(dat_,dat,size(dat),mpi_double_precision,mpi_max,icomm)
+      if (info ==0) &
+           & call mpi_allreduce(dat_,dat,size(dat),mpi_double_precision,mpi_max,icomm)
     else
       if (iam==root_) then 
         call psb_realloc(size(dat),dat_,info)
@@ -639,6 +701,7 @@ contains
         call mpi_reduce(dat,dat_,size(dat),mpi_double_precision,mpi_max,root_,icomm)
       end if
     endif
+#endif    
   end subroutine psb_dmaxv
   subroutine psb_dmaxm(ictxt,dat,root)
     use mpi
@@ -650,6 +713,7 @@ contains
     real(kind(1.d0)), allocatable :: dat_(:,:)
     integer :: iam, np, icomm, info
     
+#if !defined(SERIAL_MPI)
 
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
@@ -662,7 +726,8 @@ contains
     if (root_ == -1) then 
       call psb_realloc(size(dat,1),size(dat,2),dat_,info)
       dat_ = dat
-      if (info ==0) call mpi_allreduce(dat_,dat,size(dat),mpi_double_precision,mpi_max,icomm)
+      if (info ==0)&
+           & call mpi_allreduce(dat_,dat,size(dat),mpi_double_precision,mpi_max,icomm)
     else
       if (iam==root_) then 
         call psb_realloc(size(dat,1),size(dat,2),dat_,info)
@@ -672,6 +737,7 @@ contains
         call mpi_reduce(dat,dat_,size(dat),mpi_double_precision,mpi_max,root_,icomm)
       end if
     endif
+#endif    
   end subroutine psb_dmaxm
   
   
@@ -683,6 +749,7 @@ contains
     integer :: root_, dat_
     integer :: iam, np, icomm
     
+#if !defined(SERIAL_MPI)
 
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
@@ -699,6 +766,7 @@ contains
       call mpi_reduce(dat,dat_,1,mpi_integer,mpi_min,root_,icomm)
       dat = dat_
     endif
+#endif    
   end subroutine psb_imins
   subroutine psb_iminv(ictxt,dat,root)
     use mpi
@@ -711,6 +779,7 @@ contains
     integer :: iam, np, icomm, info
     
 
+#if !defined(SERIAL_MPI)
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
 
@@ -730,6 +799,7 @@ contains
         call mpi_reduce(dat,dat_,size(dat),mpi_integer,mpi_min,root_,icomm)
       end if
     endif
+#endif    
   end subroutine psb_iminv
   subroutine psb_iminm(ictxt,dat,root)
     use mpi
@@ -742,6 +812,7 @@ contains
     integer :: iam, np, icomm, info
     
 
+#if !defined(SERIAL_MPI)
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
 
@@ -761,6 +832,7 @@ contains
         call mpi_reduce(dat,dat_,size(dat),mpi_integer,mpi_min,root_,icomm)
       end if
     endif
+#endif    
   end subroutine psb_iminm
   
   subroutine psb_dmins(ictxt,dat,root)
@@ -773,6 +845,7 @@ contains
     integer :: iam, np, icomm
     
 
+#if !defined(SERIAL_MPI)
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
 
@@ -788,6 +861,7 @@ contains
       call mpi_reduce(dat,dat_,1,mpi_double_precision,mpi_min,root_,icomm)
       dat = dat_
     endif
+#endif    
   end subroutine psb_dmins
   subroutine psb_dminv(ictxt,dat,root)
     use mpi
@@ -800,6 +874,7 @@ contains
     integer :: iam, np, icomm, info
     
 
+#if !defined(SERIAL_MPI)
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
 
@@ -811,7 +886,8 @@ contains
     if (root_ == -1) then 
       call psb_realloc(size(dat),dat_,info)
       dat_ = dat
-      if (info ==0) call mpi_allreduce(dat_,dat,size(dat),mpi_double_precision,mpi_min,icomm)
+      if (info ==0) &
+           & call mpi_allreduce(dat_,dat,size(dat),mpi_double_precision,mpi_min,icomm)
     else
       if (iam==root_) then 
         call psb_realloc(size(dat),dat_,info)
@@ -821,6 +897,7 @@ contains
         call mpi_reduce(dat,dat_,size(dat),mpi_double_precision,mpi_min,root_,icomm)
       end if
     endif
+#endif    
   end subroutine psb_dminv
   subroutine psb_dminm(ictxt,dat,root)
     use mpi
@@ -832,6 +909,7 @@ contains
     real(kind(1.d0)), allocatable :: dat_(:,:)
     integer :: iam, np, icomm, info
     
+#if !defined(SERIAL_MPI)
 
     call psb_info(ictxt,iam,np)
     call psb_get_mpicomm(ictxt,icomm)
@@ -844,7 +922,8 @@ contains
     if (root_ == -1) then 
       call psb_realloc(size(dat,1),size(dat,2),dat_,info)
       dat_ = dat
-      if (info ==0) call mpi_allreduce(dat_,dat,size(dat),mpi_double_precision,mpi_min,icomm)
+      if (info ==0) &
+           & call mpi_allreduce(dat_,dat,size(dat),mpi_double_precision,mpi_min,icomm)
     else
       if (iam==root_) then 
         call psb_realloc(size(dat,1),size(dat,2),dat_,info)
@@ -854,6 +933,8 @@ contains
         call mpi_reduce(dat,dat_,size(dat),mpi_double_precision,mpi_min,root_,icomm)
       end if
     endif
+#endif    
+
   end subroutine psb_dminm
   
   
@@ -865,6 +946,11 @@ contains
     
     integer   :: root_
     
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -875,6 +961,7 @@ contains
     else
       call gamx2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_iamxs
 
   subroutine psb_iamxv(ictxt,dat,root,ia)
@@ -886,6 +973,12 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:)
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -897,6 +990,7 @@ contains
     else
       call gamx2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_iamxv
 
   subroutine psb_iamxm(ictxt,dat,root,ia)
@@ -908,6 +1002,12 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:,:)
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -919,6 +1019,7 @@ contains
     else
       call gamx2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_iamxm
 
 
@@ -930,6 +1031,12 @@ contains
     
     integer   :: root_
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -940,6 +1047,7 @@ contains
     else
       call gamx2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_damxs
 
   subroutine psb_damxv(ictxt,dat,root,ia)
@@ -951,6 +1059,12 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:)
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -962,6 +1076,7 @@ contains
     else
       call gamx2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_damxv
 
   subroutine psb_damxm(ictxt,dat,root,ia)
@@ -973,6 +1088,12 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:,:)
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -984,6 +1105,7 @@ contains
     else
       call gamx2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_damxm
 
 
@@ -995,6 +1117,12 @@ contains
     
     integer   :: root_
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -1005,6 +1133,7 @@ contains
     else
       call gamx2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_zamxs
 
   subroutine psb_zamxv(ictxt,dat,root,ia)
@@ -1016,6 +1145,12 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:)
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -1027,6 +1162,7 @@ contains
     else
       call gamx2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_zamxv
 
   subroutine psb_zamxm(ictxt,dat,root,ia)
@@ -1038,6 +1174,12 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:,:)
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -1049,6 +1191,7 @@ contains
     else
       call gamx2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_zamxm
 
 
@@ -1061,6 +1204,12 @@ contains
     
     integer   :: root_
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -1071,6 +1220,7 @@ contains
     else
       call gamn2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_iamns
 
   subroutine psb_iamnv(ictxt,dat,root,ia)
@@ -1082,6 +1232,12 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:)
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -1093,6 +1249,7 @@ contains
     else
       call gamn2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_iamnv
 
   subroutine psb_iamnm(ictxt,dat,root,ia)
@@ -1104,6 +1261,12 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:,:)
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -1115,6 +1278,7 @@ contains
     else
       call gamn2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_iamnm
 
 
@@ -1126,6 +1290,12 @@ contains
     
     integer   :: root_
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -1136,6 +1306,7 @@ contains
     else
       call gamn2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_damns
 
   subroutine psb_damnv(ictxt,dat,root,ia)
@@ -1147,6 +1318,12 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:)
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -1158,6 +1335,7 @@ contains
     else
       call gamn2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_damnv
 
   subroutine psb_damnm(ictxt,dat,root,ia)
@@ -1169,6 +1347,12 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:,:)
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -1180,6 +1364,7 @@ contains
     else
       call gamn2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_damnm
 
 
@@ -1191,6 +1376,12 @@ contains
     
     integer   :: root_
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -1201,6 +1392,7 @@ contains
     else
       call gamn2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_zamns
 
   subroutine psb_zamnv(ictxt,dat,root,ia)
@@ -1212,6 +1404,12 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:)
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -1223,6 +1421,7 @@ contains
     else
       call gamn2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_zamnv
 
   subroutine psb_zamnm(ictxt,dat,root,ia)
@@ -1234,6 +1433,12 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:,:)
     
+    
+#if defined(SERIAL_MPI) 
+    if (present(ia)) then 
+      ia = 0
+    end if
+#else
     if (present(root)) then 
       root_ = root
     else
@@ -1245,6 +1450,7 @@ contains
     else
       call gamn2d(ictxt,'A',dat,rrt=root_) 
     endif
+#endif    
   end subroutine psb_zamnm
 
 
@@ -1256,6 +1462,7 @@ contains
     
     integer   :: root_
     
+#if !defined(SERIAL_MPI)
     if (present(root)) then 
       root_ = root
     else
@@ -1263,6 +1470,7 @@ contains
     endif
 
     call gsum2d(ictxt,'A',dat,rrt=root_) 
+#endif    
 
   end subroutine psb_isums
 
@@ -1273,6 +1481,7 @@ contains
     
     integer   :: root_
     
+#if !defined(SERIAL_MPI)
     if (present(root)) then 
       root_ = root
     else
@@ -1280,6 +1489,7 @@ contains
     endif
     
     call gsum2d(ictxt,'A',dat,rrt=root_) 
+#endif    
   end subroutine psb_isumv
 
   subroutine psb_isumm(ictxt,dat,root)
@@ -1289,6 +1499,7 @@ contains
     
     integer   :: root_
     
+#if !defined(SERIAL_MPI)
     if (present(root)) then 
       root_ = root
     else
@@ -1297,6 +1508,7 @@ contains
     endif
 
     call gsum2d(ictxt,'A',dat,rrt=root_) 
+#endif    
 
   end subroutine psb_isumm
 
@@ -1308,6 +1520,7 @@ contains
     
     integer   :: root_
     
+#if !defined(SERIAL_MPI)
     if (present(root)) then 
       root_ = root
     else
@@ -1315,6 +1528,7 @@ contains
     endif
 
     call gsum2d(ictxt,'A',dat,rrt=root_) 
+#endif    
 
   end subroutine psb_dsums
 
@@ -1325,6 +1539,7 @@ contains
     
     integer   :: root_
     
+#if !defined(SERIAL_MPI)
     if (present(root)) then 
       root_ = root
     else
@@ -1332,6 +1547,7 @@ contains
     endif
 
     call gsum2d(ictxt,'A',dat,rrt=root_) 
+#endif    
 
   end subroutine psb_dsumv
 
@@ -1342,6 +1558,7 @@ contains
     
     integer   :: root_
     
+#if !defined(SERIAL_MPI)
     if (present(root)) then 
       root_ = root
     else
@@ -1350,6 +1567,7 @@ contains
     
     call gsum2d(ictxt,'A',dat,rrt=root_) 
 
+#endif    
   end subroutine psb_dsumm
 
 
@@ -1360,6 +1578,7 @@ contains
     
     integer   :: root_
     
+#if !defined(SERIAL_MPI)
     if (present(root)) then 
       root_ = root
     else
@@ -1367,6 +1586,7 @@ contains
     endif
 
     call gsum2d(ictxt,'A',dat,rrt=root_) 
+#endif    
 
   end subroutine psb_zsums
 
@@ -1378,6 +1598,7 @@ contains
     integer   :: root_
     integer, allocatable :: cia(:)
     
+#if !defined(SERIAL_MPI)
     if (present(root)) then 
       root_ = root
     else
@@ -1385,6 +1606,7 @@ contains
     endif
 
     call gsum2d(ictxt,'A',dat,rrt=root_) 
+#endif    
 
   end subroutine psb_zsumv
 
@@ -1395,6 +1617,7 @@ contains
     
     integer   :: root_
     
+#if !defined(SERIAL_MPI)
     if (present(root)) then 
       root_ = root
     else
@@ -1403,11 +1626,13 @@ contains
     
     call gsum2d(ictxt,'A',dat,rrt=root_) 
 
+#endif    
   end subroutine psb_zsumm
 
 
 
   subroutine psb_hsnds(ictxt,dat,dst,length)
+    use psb_error_mod
     integer, intent(in)           :: ictxt
     character(len=*), intent(in)  :: dat
     integer, intent(in)           :: dst
@@ -1415,6 +1640,11 @@ contains
     integer, allocatable          :: buffer(:)
     integer :: length_, i
     
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >1) then 
+      write(0,*) "Warning: process sending a message in serial mode (to itself)"
+    endif
+#else
     if (present(length)) then 
       length_ = length
     else
@@ -1426,10 +1656,11 @@ contains
     end do
     
     call gesd2d(ictxt,buffer,dst,0) 
-
+#endif
   end subroutine psb_hsnds
 
   subroutine psb_hrcvs(ictxt,dat,src,length)
+    use psb_error_mod
     integer, intent(in)           :: ictxt
     character(len=*), intent(out)  :: dat
     integer, intent(in)           :: src
@@ -1437,6 +1668,12 @@ contains
     integer, allocatable          :: buffer(:)
     integer :: length_, i
     
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >0) then 
+      write(0,*) "Warning: process receiving a message in serial mode (to itself)"
+    endif
+    dat = ''
+#else
     if (present(length)) then 
       length_ = length
     else
@@ -1448,208 +1685,357 @@ contains
     do i=1,length_
       dat(i:i) = achar(buffer(i))
     end do
+#endif    
 
   end subroutine psb_hrcvs
 
   subroutine psb_lsnds(ictxt,dat,dst,length)
+    use psb_error_mod
     integer, intent(in)           :: ictxt
     logical, intent(in)           :: dat
     integer, intent(in)           :: dst
     integer :: i
     
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >1) then 
+      write(0,*) "Warning: process sending a message in serial mode (to itself)"
+    endif
+#else
     if (dat) then 
       i = 1
     else
       i = 0
     endif
     call gesd2d(ictxt,i,dst,0) 
+#endif    
 
   end subroutine psb_lsnds
 
   subroutine psb_lrcvs(ictxt,dat,src,length)
+    use psb_error_mod
     integer, intent(in)           :: ictxt
     logical, intent(out)          :: dat
     integer, intent(in)           :: src
     integer :: i
     
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >0) then 
+      write(0,*) "Warning: process receiving a message in serial mode (to itself)"
+    endif
+    dat = .false.
+#else
     call gerv2d(ictxt,i,src,0) 
 
     dat = (i == 1) 
+#endif    
 
   end subroutine psb_lrcvs
 
 
   subroutine psb_isnds(ictxt,dat,dst)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     integer, intent(in)  :: dat
     integer, intent(in)  :: dst
     
-
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >1) then 
+      write(0,*) "Warning: process sending a message in serial mode (to itself)"
+    endif
+#else
     call gesd2d(ictxt,dat,dst,0) 
+#endif    
 
   end subroutine psb_isnds
 
   subroutine psb_isndv(ictxt,dat,dst)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     integer, intent(in)  :: dat(:)
     integer, intent(in)  :: dst
 
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >1) then 
+      write(0,*) "Warning: process sending a message in serial mode (to itself)"
+    endif
+#else
     call gesd2d(ictxt,dat,dst,0) 
+#endif    
 
   end subroutine psb_isndv
 
   subroutine psb_isndm(ictxt,dat,dst)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     integer, intent(in)  :: dat(:,:)
     integer, intent(in)  :: dst
 
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >1) then 
+      write(0,*) "Warning: process sending a message in serial mode (to itself)"
+    endif
+#else
     call gesd2d(ictxt,dat,dst,0) 
+#endif    
 
   end subroutine psb_isndm
 
 
   subroutine psb_dsnds(ictxt,dat,dst)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     real(kind(1.d0)), intent(in)  :: dat
     integer, intent(in)  :: dst
     
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >1) then 
+      write(0,*) "Warning: process sending a message in serial mode (to itself)"
+    endif
+#else
 
     call gesd2d(ictxt,dat,dst,0) 
+#endif    
 
   end subroutine psb_dsnds
 
   subroutine psb_dsndv(ictxt,dat,dst)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     real(kind(1.d0)), intent(in)  :: dat(:)
     integer, intent(in)  :: dst
 
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >1) then 
+      write(0,*) "Warning: process sending a message in serial mode (to itself)"
+    endif
+#else
     call gesd2d(ictxt,dat,dst,0) 
+#endif    
 
   end subroutine psb_dsndv
 
   subroutine psb_dsndm(ictxt,dat,dst)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     real(kind(1.d0)), intent(in)  :: dat(:,:)
     integer, intent(in)  :: dst
 
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >1) then 
+      write(0,*) "Warning: process sending a message in serial mode (to itself)"
+    endif
+#else
     call gesd2d(ictxt,dat,dst,0) 
+#endif    
 
   end subroutine psb_dsndm
 
 
   subroutine psb_zsnds(ictxt,dat,dst)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     complex(kind(1.d0)), intent(in)  :: dat
     integer, intent(in)  :: dst
     
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >1) then 
+      write(0,*) "Warning: process sending a message in serial mode (to itself)"
+    endif
+#else
 
     call gesd2d(ictxt,dat,dst,0) 
+#endif    
 
   end subroutine psb_zsnds
   
   subroutine psb_zsndv(ictxt,dat,dst)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     complex(kind(1.d0)), intent(in)  :: dat(:)
     integer, intent(in)  :: dst
 
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >1) then 
+      write(0,*) "Warning: process sending a message in serial mode (to itself)"
+    endif
+#else
     call gesd2d(ictxt,dat,dst,0) 
+#endif    
 
   end subroutine psb_zsndv
 
   subroutine psb_zsndm(ictxt,dat,dst)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     complex(kind(1.d0)), intent(in)  :: dat(:,:)
     integer, intent(in)  :: dst
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >1) then 
+      write(0,*) "Warning: process sending a message in serial mode (to itself)"
+    endif
+#else
 
     call gesd2d(ictxt,dat,dst,0) 
+#endif    
 
   end subroutine psb_zsndm
 
 
 
   subroutine psb_ircvs(ictxt,dat,src)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     integer, intent(inout)  :: dat
     integer, intent(in)  :: src
-    
-
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >0) then 
+      write(0,*) "Warning: process receiving a message in serial mode (to itself)"
+    endif
+    dat = 0
+#else
     call gerv2d(ictxt,dat,src,0) 
+#endif    
 
   end subroutine psb_ircvs
 
   subroutine psb_ircvv(ictxt,dat,src)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     integer, intent(inout)  :: dat(:)
     integer, intent(in)  :: src
 
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >0) then 
+      write(0,*) "Warning: process receiving a message in serial mode (to itself)"
+    endif
+    dat = 0
+#else
     call gerv2d(ictxt,dat,src,0) 
+#endif    
 
   end subroutine psb_ircvv
 
   subroutine psb_ircvm(ictxt,dat,src)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     integer, intent(inout)  :: dat(:,:)
     integer, intent(in)  :: src
 
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >0) then 
+      write(0,*) "Warning: process receiving a message in serial mode (to itself)"
+    endif
+    dat = 0
+#else
+
     call gerv2d(ictxt,dat,src,0) 
+#endif    
 
   end subroutine psb_ircvm
 
 
   subroutine psb_drcvs(ictxt,dat,src)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     real(kind(1.d0)), intent(inout)  :: dat
     integer, intent(in)  :: src
     
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >0) then 
+      write(0,*) "Warning: process receiving a message in serial mode (to itself)"
+    endif
+    dat = 0
+#else
 
     call gerv2d(ictxt,dat,src,0) 
+#endif    
 
   end subroutine psb_drcvs
 
   subroutine psb_drcvv(ictxt,dat,src)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     real(kind(1.d0)), intent(inout)  :: dat(:)
     integer, intent(in)  :: src
 
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >0) then 
+      write(0,*) "Warning: process receiving a message in serial mode (to itself)"
+    endif
+    dat = 0
+#else
     call gerv2d(ictxt,dat,src,0) 
+#endif    
 
   end subroutine psb_drcvv
 
   subroutine psb_drcvm(ictxt,dat,src)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     real(kind(1.d0)), intent(inout)  :: dat(:,:)
     integer, intent(in)  :: src
 
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >0) then 
+      write(0,*) "Warning: process receiving a message in serial mode (to itself)"
+    endif
+    dat = 0
+#else
     call gerv2d(ictxt,dat,src,0) 
+#endif    
 
   end subroutine psb_drcvm
 
 
   subroutine psb_zrcvs(ictxt,dat,src)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     complex(kind(1.d0)), intent(inout)  :: dat
     integer, intent(in)  :: src
     
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >0) then 
+      write(0,*) "Warning: process receiving a message in serial mode (to itself)"
+    endif
+    dat = 0
+#else
 
     call gerv2d(ictxt,dat,src,0) 
+#endif    
 
   end subroutine psb_zrcvs
   
   subroutine psb_zrcvv(ictxt,dat,src)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     complex(kind(1.d0)), intent(inout)  :: dat(:)
     integer, intent(in)  :: src
 
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >0) then 
+      write(0,*) "Warning: process receiving a message in serial mode (to itself)"
+    endif
+    dat = 0
+#else
     call gerv2d(ictxt,dat,src,0) 
+#endif    
 
   end subroutine psb_zrcvv
 
   subroutine psb_zrcvm(ictxt,dat,src)
+    use psb_error_mod
     integer, intent(in)  :: ictxt
     complex(kind(1.d0)), intent(inout)  :: dat(:,:)
     integer, intent(in)  :: src
 
+#if defined(SERIAL_MPI) 
+    if (psb_get_errverbosity() >0) then 
+      write(0,*) "Warning: process receiving a message in serial mode (to itself)"
+    endif
+    dat = 0
+#else
     call gerv2d(ictxt,dat,src,0) 
+#endif    
 
   end subroutine psb_zrcvm
 
@@ -1658,7 +2044,7 @@ contains
 
 
 
-
+#if !defined(SERIAL_MPI)
   
   subroutine igebs2ds(ictxt,scope,dat,top)
     integer, intent(in)   :: ictxt,dat
@@ -4398,6 +4784,7 @@ contains
     end if
       
   end subroutine zgamn2dm
+#endif    
   
 
 end module psb_penv_mod
diff --git a/base/psblas/pdtreecomb.f b/base/psblas/pdtreecomb.F
similarity index 99%
rename from base/psblas/pdtreecomb.f
rename to base/psblas/pdtreecomb.F
index 0aecf730..b95a5475 100644
--- a/base/psblas/pdtreecomb.f
+++ b/base/psblas/pdtreecomb.F
@@ -100,8 +100,10 @@ C
       DOUBLE PRECISION   HIS( 2 )
 *     ..
 *     .. External Subroutines ..
+#if !defined(SERIAL_MPI)
       EXTERNAL           BLACS_GRIDINFO, DGEBR2D, DGEBS2D,
      $                   DGERV2D, DGESD2D
+#endif    
 *     ..
 *     .. External Functions ..
       LOGICAL            LSAME
@@ -122,6 +124,8 @@ C
          TRDEST = RDEST0
          TCDEST = CDEST0
       END IF
+#if  !defined(SERIAL_MPI)
+
 *
 *     Get grid parameters.
 *
@@ -234,6 +238,7 @@ C
      $                    TRDEST, TCDEST )
          END IF
       END IF
+#endif    
 *
       RETURN
 *
diff --git a/base/tools/psb_cd_inloc.f90 b/base/tools/psb_cd_inloc.f90
index ea308925..b7a89237 100644
--- a/base/tools/psb_cd_inloc.f90
+++ b/base/tools/psb_cd_inloc.f90
@@ -69,12 +69,18 @@ subroutine psb_cd_inloc(v, ictxt, desc_a, info)
   call psb_info(ictxt, me, np)
   if (debug) write(*,*) 'psb_cdall: ',np,me
 
-
-  loc_row = size(v)
-  m       = loc_row
-  call psb_sum(ictxt,m)
-
+  
+  if (.false.) then 
+    loc_row = size(v)
+    m       = loc_row
+    call psb_sum(ictxt,m)
+  else
+    m = maxval(v)
+    call psb_max(ictxt,m)
+  end if
+        
   n = m
+    
   !... check m and n parameters....
   if (m < 1) then
     info = 10
diff --git a/base/tools/psb_icdasb.f90 b/base/tools/psb_icdasb.f90
index d8677c31..d8014a8c 100644
--- a/base/tools/psb_icdasb.f90
+++ b/base/tools/psb_icdasb.f90
@@ -37,6 +37,7 @@
 !    desc_a  - type(<psb_desc_type>).         The communication descriptor.
 !    info    - integer.                       Eventually returns an error code.
 subroutine psb_icdasb(desc_a,info,ext_hv)
+  use mpi
   use psb_descriptor_type
   use psb_serial_mod
   use psb_const_mod
@@ -44,8 +45,6 @@ subroutine psb_icdasb(desc_a,info,ext_hv)
   use psb_error_mod
   use psb_penv_mod
   implicit none
-
-  include 'mpif.h'
   !...Parameters....
   type(psb_desc_type), intent(inout) :: desc_a
   integer, intent(out)               :: info
diff --git a/base/tools/psb_zsphalo.f90 b/base/tools/psb_zsphalo.f90
index f45ca835..e796ea89 100644
--- a/base/tools/psb_zsphalo.f90
+++ b/base/tools/psb_zsphalo.f90
@@ -121,14 +121,14 @@ Subroutine psb_zsphalo(a,desc_a,blk,info,rwcnv,clcnv,outfmt)
   sdsz(:)=0
   rvsz(:)=0
   ipx = 1
+  blk%k = a%k
+  blk%m = 0 
   brvindx(ipx) = 0
   bsdindx(ipx) = 0
   counter=1
   idx = 0
   idxs = 0
   idxr = 0
-  blk%k = a%k
-  blk%m = 0 
   ! For all rows in the halo descriptor, extract and send/receive.
   Do 
     proc=desc_a%halo_index(counter)
diff --git a/baseprec/psb_zbaseprc_aply.f90 b/baseprec/psb_zbaseprc_aply.f90
index 824a288c..cdabda41 100644
--- a/baseprec/psb_zbaseprc_aply.f90
+++ b/baseprec/psb_zbaseprc_aply.f90
@@ -52,7 +52,7 @@ subroutine psb_zbaseprc_aply(alpha,prec,x,beta,y,desc_data,trans,work,info)
   character     ::diagl, diagu
   integer :: ictxt,np,me,i, isz, nrg, err_act
   real(kind(1.d0)) :: t1, t2, t3, t4, t5, t6, t7
-  logical,parameter                 :: debug=.false., debugprt=.
+  logical,parameter                 :: debug=.false., debugprt=.false.
   character(len=20)   :: name, ch_err
 
   interface psb_bjac_aply
diff --git a/test/fileread/runs/dfs.inp b/test/fileread/runs/dfs.inp
index 1fcfb735..a1b9913c 100644
--- a/test/fileread/runs/dfs.inp
+++ b/test/fileread/runs/dfs.inp
@@ -1,5 +1,5 @@
 10                  Number of inputs
-young1r.mtx         This (and others) from: http://math.nist.gov/MatrixMarket/  or 
+lapl600x600.mtx      young1r.mtx         This (and others) from: http://math.nist.gov/MatrixMarket/  or 
 NONE                       http://www.cise.ufl.edu/research/sparse/matrices/index.html
 BICGSTAB   
 CSR
@@ -7,6 +7,6 @@ CSR
 1                   ISTOPC
 00800               ITMAX
 -1                  ITRACE
-4                   IPREC       0:NONE  1:DIAGSC  2:ILU  3: AS 4: RAS 5: ASH 6: RASH
+2                   IPREC       0:NONE  1:DIAGSC  2:ILU  
 1                   ML
 1.d-6               EPS