mld2p4:

krylov/Makefile

@@ -14,7 +14,8 @@ PSBKRYLDIR=$(PSBLASDIR)/krylov
 
 METHDOBJS=psb_dcgstab.o psb_dcg.o psb_dcgs.o \
 	psb_dbicg.o psb_dcgstabl.o psb_drgmres.o\
-	psb_zcgstab.o psb_zcgs.o psb_zrgmres.o
+	psb_zcgstab.o psb_zcg.o psb_zcgs.o  \
+	psb_zbicg.o psb_zcgstabl.o psb_zrgmres.o
 
 LIBMOD=psb_krylov_mod$(.mod) psb_prec_mod$(.mod)
 MODOBJS=$(LIBMOD:$(.mod)=.o)
@@ -29,7 +30,7 @@ lib: $(OBJS)
 	/bin/cp -p $(HERE)/$(LIBNAME) $(LIBDIR)
 	/bin/cp -p $(LIBMOD) $(LIBDIR)
 
-$(METHDOBJS): psb_prec_mod.o
+$(METHDOBJS): psb_prec_mod.o psb_krylov_mod.o
 
 symlink:
 	(/bin/ln -fs $(PSBKRYLDIR)/*.f90 . )

mlprec/mld_das_bld.f90

@@ -41,7 +41,9 @@
 !
 !  This routine builds the Additive Schwarz (AS) preconditioner.
 !  If the preconditioner is the block-Jacobi one, the routine makes only a copy of
-!  the descriptor of the original matrix.
+!  the descriptor of the original matrix and then proceeds to call mld_fact_bld
+!  for LU or incomplete LU factorization of the diagonal blocks of the
+!  distributed matrix.
 !    
 !
 ! Arguments:

mlprec/mld_dbaseprec_bld.f90

@@ -154,32 +154,7 @@ subroutine mld_dbaseprc_bld(a,desc_a,p,info,upd)
       goto 9999
     end if
 
-  case(mld_bjac_)
+  case(mld_bjac_,mld_as_)
-    ! Block Jacobi preconditioner/smoother
-
-    call mld_check_def(p%iprcparm(mld_sub_ren_),'renumbering',&
-         &  mld_renum_none_,is_legal_renum)
-    call mld_check_def(p%iprcparm(mld_sub_solve_),'fact',&
-         &  mld_ilu_n_,is_legal_ml_fact)
-
-    call psb_cdcpy(desc_a,p%desc_data,info)
-    if(info /= 0) then
-      info=4010
-      ch_err='psb_cdcpy'
-      call psb_errpush(info,name,a_err=ch_err)
-      goto 9999
-    end if
-
-    ! Build the local part of the base preconditioner/smoother
-    call mld_fact_bld(a,p,iupd,info)
-    if(info /= 0) then
-      info=4010
-      call psb_errpush(info,name,a_err='mld_fact_bld')
-      goto 9999
-    end if
-
-
-  case(mld_as_)
     ! Additive Schwarz preconditioners/smoothers
 
     call mld_check_def(p%iprcparm(mld_n_ovr_),'overlap',&

mlprec/mld_dfact_bld.f90

@@ -39,34 +39,35 @@
 ! Subroutine: mld_dfact_bld
 ! Version:    real
 !
-!  This routine computes an LU or incomplete LU factorization of the input
+!  This routine computes an LU or incomplete LU factorization of the diagonal blocks
-!  matrix, according to the value of p%iprcparm(iprcparm(sub_solve_),
+!  of a distributed matrix, according to the value of p%iprcparm(iprcparm(sub_solve_), 
 !  set by the user through mld_dprecinit or mld_dprecset.
-!  It may also split the local matrix into its block-diagonal and
+!  It may also split the matrix into its block-diagonal and
 !  off block-diagonal parts, for the future application of multiple
 !  block-Jacobi sweeps.
 !
-!  This routine is used by mld_dbaseprec_bld, to build a 'base' block-Jacobi or
+!  This routine is used by mld_as_bld, to build a 'base' block-Jacobi or
 !  Additive Schwarz (AS) preconditioner at any level of a multilevel preconditioner,
 !  or a block-Jacobi or LU or ILU solver at the coarsest level of a multilevel
 !  preconditioner. For the Additive Schwarz, it is called from mld_as_bld,
 !  which prepares the overlap descriptor and retrieves the remote rows into blck.
 !
-!  More precisely, the routine  performs one of the following tasks: 
+!  More precisely, the routine performs one of the following tasks: 
 !
-!  1. construction of a block-Jacobi preconditioner associated
+!  1. LU or ILU factorization of the diagonal blocks of the distributed matrix
-!     to a matrix A distributed among the processes (allowed at any level);
+!     for the construction of a block-Jacobi or AS preconditioners
+!     (allowed at any level);
 !
 !  2. setup of block-Jacobi sweeps to compute an approximate solution of a
 !     linear system
 !                                    A*Y = X,
 !     distributed among the processes (allowed only at the coarsest level);
 !
-!  3. LU factorization of a linear system
+!  3. LU factorization of the matrix of a linear system
 !                                    A*Y = X,
 !     distributed among the processes (allowed only at the coarsest level);
 !
-!  4. LU or incomplete LU factorization of a linear system
+!  4. LU or incomplete LU factorization of the matrix of a linear system
 !                                    A*Y = X,
 !     replicated on the processes (allowed only at the coarsest level).
 !
@@ -84,7 +85,7 @@
 ! Arguments:
 !    a       -  type(psb_dspmat_type), input.
 !               The sparse matrix structure containing the local part of the
-!               matrix to be preconditioned or factorized.
+!               distributed matrix.
 !    p       -  type(mld_dbaseprec_type), input/output.
 !               The 'base preconditioner' data structure containing the local 
 !               part of the preconditioner or solver at the current level.
@@ -98,7 +99,7 @@
 !               the new preconditioner.
 !    blck    -  type(psb_dspmat_type), input, optional.
 !               The sparse matrix structure containing the remote rows of the
-!               matrix to be factorized, that have been retrieved by mld_as_bld
+!               distributed matrix, that have been retrieved by mld_as_bld
 !               to build an Additive Schwarz base preconditioner with overlap
 !               greater than 0. If the overlap is 0 blck is empty.
 !  
@@ -290,8 +291,6 @@ subroutine mld_dfact_bld(a,p,upd,info,blck)
     ! No reordering of the local matrix is required
     !
   case(0)
-
-
     !
     ! In case of multiple block-Jacobi sweeps, clip into p%av(ap_nd_)
     ! the off block-diagonal part of the local extended matrix. The
@@ -333,7 +332,6 @@ subroutine mld_dfact_bld(a,p,upd,info,blck)
         goto 9999
       end if
     end if
-
     ! 
     ! Compute a factorization of the diagonal block of the local matrix,
     ! according to the choice made by the user by setting p%iprcparm(sub_solve_)

mlprec/mld_dilu0_fact.f90

@@ -41,20 +41,20 @@
 ! Contains:   mld_dilu0_factint, ilu_copyin
 !
 !  This routine computes either the ILU(0) or the MILU(0) factorization of the
-!  local part of the matrix stored into a. These factorizations are used to
+!  diagonal blocks of a distributed matrix. These factorizations 
-!  build the 'base preconditioner' (block-Jacobi preconditioner/solver, Additive
+!  are used to build the 'base preconditioner' (block-Jacobi preconditioner/solver, 
-!  Schwarz preconditioner) corresponding to a certain level of a multilevel
+!  Additive Schwarz preconditioner) corresponding to a given level of a multilevel
 !  preconditioner.
 !
 !  Details on the above factorizations can be found in
 !    Y. Saad, Iterative Methods for Sparse Linear Systems, Second Edition,
 !    SIAM, 2003, Chapter 10.
 !
-!  The local matrix to be factorized is stored into a and blck, as specified
+!  The local matrix is stored into a and blck, as specified in the description 
-!  in the description of the arguments below. The storage format for both the
+!  of the arguments below. The storage format for both the L and U factors is CSR. 
-!  L and U factors is CSR. The diagonal of the U factor is stored separately
+!  The diagonal of the U factor is stored separately (actually, the inverse of the 
-!  (actually, the inverse of the diagonal entries is stored; this is then
+!  diagonal entries is stored; this is then managed in the solve stage associated 
-!  managed in the solve stage associated to the ILU(0)/MILU(0) factorization).
+!  to the ILU(0)/MILU(0) factorization).
 !
 !  The routine copies and factors "on the fly" from a and blck into l (L factor),
 !  u (U factor, except its diagonal) and d (diagonal of U).
@@ -69,11 +69,11 @@
 !               The MILU(0) factorization is computed if ialg = 2 (= mld_milu_n_);
 !               the ILU(0) factorization otherwise.
 !    a       -  type(psb_dspmat_type), input.
-!               The sparse matrix structure containing the local matrix to be
+!               The sparse matrix structure containing the local matrix.
-!               factorized. Note that if the 'base' Additive Schwarz preconditioner
+!               Note that if the 'base' Additive Schwarz preconditioner
 !               has overlap greater than 0 and the matrix has not been reordered
-!               (see mld_bjac_bld), then a contains     only the 'original' local part
+!               (see mld_as_bld), then a contains only the 'original' local part
-!               of the matrix to be factorized, i.e. the rows of the matrix held
+!               of the distributed matrix, i.e. the rows of the matrix held
 !               by the calling process according to the initial data distribution.
 !    l       -  type(psb_dspmat_type), input/output.
 !               The L factor in the incomplete factorization.
@@ -92,10 +92,10 @@
 !               Error code.
 !    blck    -  type(psb_dspmat_type), input, optional, target.
 !               The sparse matrix structure containing the remote rows of the
-!               matrix to be factorized, that have been retrieved by mld_asmat_bld
+!               distributed matrix, that have been retrieved by mld_as_bld
 !               to build an Additive Schwarz base preconditioner with overlap
 !               greater than 0. If the overlap is 0 or the matrix has been reordered
-!               (see mld_bjac_bld), then blck is empty.
+!               (see mld_fact_bld), then blck is empty.
 !  
 subroutine mld_dilu0_fact(ialg,a,l,u,d,info,blck)
 
@@ -205,12 +205,13 @@ contains
   ! Version:    real
   ! Note: internal subroutine of mld_dilu0_fact.
   !
-  !  This routine computes either the ILU(0) or the MILU(0) factorization of the
+  !  This routine computes either the ILU(0) or the MILU(0) factorization of the 
-  !  local part of the matrix stored into a. These factorizations are used to build
+  !  diagonal blocks of a distributed matrix. 
-  !  the 'base preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz
+  !  These factorizations are used to build the 'base preconditioner' 
-  !  preconditioner) corresponding to a certain level of a multilevel preconditioner.
+  !  (block-Jacobi preconditioner/solver, Additive Schwarz
+  !  preconditioner) corresponding to a given level of a multilevel preconditioner.
   !
-  !  The local matrix to be factorized is stored into a and b, as specified in the
+  !  The local matrix is stored into a and b, as specified in the
   !  description of the arguments below. The storage format for both the L and U
   !  factors is CSR. The diagonal of the U factor is stored separately (actually,
   !  the inverse of the diagonal entries is stored; this is then managed in the
@@ -232,20 +233,20 @@ contains
   !    ma      -  integer, input
   !               The number of rows of the local submatrix stored into a.
   !    a       -  type(psb_dspmat_type), input.
-  !               The sparse matrix structure containing the local matrix to be
+  !               The sparse matrix structure containing the local matrix.
-  !               factorized. Note that, if the 'base' Additive Schwarz preconditioner
+  !               Note that, if the 'base' Additive Schwarz preconditioner
   !               has overlap greater than 0 and the matrix has not been reordered
-  !               (see mld_bjac_bld), then a contains only the 'original' local part
+  !               (see mld_fact_bld), then a contains only the 'original' local part
-  !               of the matrix to be factorized, i.e. the rows of the matrix held
+  !               of the distributed matrix, i.e. the rows of the matrix held
   !               by the calling process according to the initial data distribution.
   !    mb      -  integer, input.
   !               The number of rows of the local submatrix stored into b.
   !    b       -  type(psb_dspmat_type), input.
   !               The sparse matrix structure containing the remote rows of the
-  !               matrix to be factorized, that have been retrieved by mld_asmat_bld
+  !               distributed matrix, that have been retrieved by mld_as_bld
   !               to build an Additive Schwarz base preconditioner with overlap
   !               greater than 0. If the overlap is 0 or the matrix has been
-  !               reordered (see mld_bjac_bld), then b does not contain any row.
+  !               reordered (see mld_fact_bld), then b does not contain any row.
   !    d       -  real(kind(1.d0)), dimension(:), output.
   !               The inverse of the diagonal entries of the U factor in the
   !               incomplete factorization.
@@ -486,7 +487,7 @@ contains
   !  copied into laspk, dia, uaspk row by row, through successive calls to
   !  ilu_copyin.
   !
-  !  The routine is used by mld_dilu0_factin in the computation of the ILU(0)/MILU(0)
+  !  The routine is used by mld_dilu0_factint in the computation of the ILU(0)/MILU(0)
   !  factorization of a local sparse matrix.
   !  
   !  TODO: modify the routine to allow copying into output L and U that are

mlprec/mld_dilu_bld.f90

@@ -39,9 +39,9 @@
 ! Subroutine: mld_dilu_bld
 ! Version:    real
 !
-!  This routine computes an incomplete LU (ILU) factorization of the local part
+!  This routine computes an incomplete LU (ILU) factorization of the diagonal blocks
-!  of the matrix stored into a. This factorization is used to build the 'base
+!  of a distributed matrix. This factorization is used to build 
-!  preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz
+!  the 'base preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz
 !  preconditioner) corresponding to a certain level of a multilevel preconditioner.
 !  The following factorizations are available:
 !  - ILU(k), i.e. ILU factorization with fill-in level k,
@@ -62,12 +62,12 @@
 !
 ! Arguments:
 !    a       -  type(psb_dspmat_type), input.
-!               The sparse matrix structure containing the local matrix to be
+!               The sparse matrix structure containing the local matrix.
-!               factorized. Note that if p%iprcparm(mld_n_ovr_) > 0, i.e. the
+!               Note that if p%iprcparm(mld_n_ovr_) > 0, i.e. the
 !               'base' Additive Schwarz preconditioner has overlap greater than
-!               0, and p%iprcparm(mld_sub_ren_) = 0, i.e. a      reordering of the
+!               0, and p%iprcparm(mld_sub_ren_) = 0, i.e. a reordering of the
-!               matrix has not been performed (see mld_bjac_bld), then a contains
+!               matrix has not been performed (see mld_fact_bld), then a contains
-!               only the 'original' local part of the matrix to      be factorized,
+!               only the 'original' local part of the distributed matrix,
 !               i.e. the rows of the matrix held by the calling process according
 !               to the initial data distribution.
 !    p       -  type(mld_dbaseprc_type), input/output.
@@ -81,10 +81,10 @@
 !               Error code.
 !    blck    -  type(psb_dspmat_type), input, optional.
 !               The sparse matrix structure containing the remote rows of the
-!               matrix to be factorized, that have been retrieved by mld_asmat_bld
+!               distributed matrix, that have been retrieved by mld_as_bld
 !               to build an Additive Schwarz base preconditioner with overlap
 !               greater than 0. If the overlap is 0 or the matrix has been reordered
-!               (see mld_bjac_bld), then blck does not contain any row.
+!               (see mld_fact_bld), then blck does not contain any row.
 !
 subroutine mld_dilu_bld(a,p,upd,info,blck)
 

mlprec/mld_diluk_fact.f90

@@ -41,16 +41,16 @@
 ! Contains:   mld_diluk_factint, iluk_copyin, iluk_fact, iluk_copyout.
 !
 !  This routine computes either the ILU(k) or the MILU(k) factorization of the
-!  local part of the matrix stored into a. These factorizations are used to
+!  diagonal blocks of a distributed matrix. These factorizations are used to build 
-!  build the 'base preconditioner' (block-Jacobi preconditioner/solver, Additive
+!  the 'base preconditioner' (block-Jacobi preconditioner/solver, 
-!  Schwarz preconditioner) corresponding to a certain level of a multilevel
+!  Additive Schwarz preconditioner) corresponding to a certain level of a multilevel
 !  preconditioner.
 !
 !  Details on the above factorizations can be found in
 !    Y. Saad, Iterative Methods for Sparse Linear Systems, Second Edition,
 !    SIAM, 2003, Chapter 10.
 !
-!  The local matrix to be factorized is stored into a and blck, as specified in
+!  The local matrix is stored into a and blck, as specified in
 !  the description of the arguments below. The storage format for both the L and
 !  U factors is CSR. The diagonal of the U factor is stored separately (actually,
 !  the inverse of the diagonal entries is stored; this is then managed in the solve
@@ -66,11 +66,11 @@
 !               the MILU(k) one if ialg = 2 (= mld_milu_n_); other values are
 !               not allowed.
 !    a       -  type(psb_dspmat_type), input.
-!               The sparse matrix structure containing the local matrix to be
+!               The sparse matrix structure containing the local matrix.
-!               factorized. Note that if the 'base' Additive Schwarz preconditioner
+!               Note that if the 'base' Additive Schwarz preconditioner
 !               has overlap greater than 0 and the matrix has not been reordered
-!               (see mld_bjac_bld), then a contains only the 'original' local part
+!               (see mld_fact_bld), then a contains only the 'original' local part
-!               of the matrix to be factorized, i.e. the rows of the matrix held
+!               of the distributed matrix, i.e. the rows of the matrix held
 !               by the calling process according to the initial data distribution.
 !    l       -  type(psb_dspmat_type), input/output.
 !               The L factor in the incomplete factorization.
@@ -89,10 +89,10 @@
 !               Error code.
 !    blck    -  type(psb_dspmat_type), input, optional, target.
 !               The sparse matrix structure containing the remote rows of the
-!               matrix to be factorized, that have been retrieved by mld_asmat_bld
+!               distributed matrix, that have been retrieved by mld_as_bld
 !               to build an Additive Schwarz base preconditioner with overlap
 !               greater than 0. If the overlap is 0 or the matrix has been reordered
-!               (see mld_bjac_bld), then blck does not contain any row.
+!               (see mld_fact_bld), then blck does not contain any row.
 !  
 subroutine mld_diluk_fact(fill_in,ialg,a,l,u,d,info,blck)
 
@@ -201,11 +201,11 @@ contains
   ! Note: internal subroutine of mld_diluk_fact
   !
   !  This routine computes either the ILU(k) or the MILU(k) factorization of the
-  !  local part of the matrix stored into a. These factorizations are used to build
+  !  diagonal blocks of a distributed matrix. These factorizations are used to build
   !  the 'base preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz
   !  preconditioner) corresponding to a certain level of a multilevel preconditioner.
   !
-  !  The local matrix to be factorized is stored into a and b, as specified in the
+  !  The local matrix is stored into a and b, as specified in the
   !  description of the arguments below. The storage format for both the L and U
   !  factors is CSR. The diagonal of the U factor is stored separately (actually,
   !  the inverse of the diagonal entries is stored; this is then managed in the
@@ -223,18 +223,18 @@ contains
   !               The total number of rows of the local matrix to be factorized,
   !               i.e. ma+mb.
   !    a       -  type(psb_dspmat_type), input.
-  !               The sparse matrix structure containing the local matrix to be
+  !               The sparse matrix structure containing the local matrix.
-  !               factorized. Note that, if the 'base' Additive Schwarz preconditioner
+  !               Note that, if the 'base' Additive Schwarz preconditioner
   !               has overlap greater than 0 and the matrix has not been reordered
-  !               (see mld_bjac_bld), then a contains only the 'original' local part
+  !               (see mld_fact_bld), then a contains only the 'original' local part
-  !               of the matrix to be factorized, i.e. the rows of the matrix held
+  !               of the distributed matrix, i.e. the rows of the matrix held
   !               by the calling process according to the initial data distribution.
   !    b       -  type(psb_dspmat_type), input.
   !               The sparse matrix structure containing the remote rows of the
-  !               matrix to be factorized, that have been retrieved by mld_asmat_bld
+  !               distributed matrix, that have been retrieved by mld_as_bld
   !               to build an Additive Schwarz base preconditioner with overlap
   !               greater than 0. If the overlap is 0 or the matrix has been reordered
-  !               (see mld_bjac_bld), then b does not contain   any row.
+  !               (see mld_fact_bld), then b does not contain any row.
   !    d       -  real(kind(1.d0)), dimension(:), output.
   !               The inverse of the diagonal entries of the U factor in the incomplete
   !               factorization.

mlprec/mld_dilut_fact.f90

@@ -40,8 +40,8 @@
 ! Version:    real
 ! Contains:   mld_dilut_factint, ilut_copyin, ilut_fact, ilut_copyout
 !
-!  This routine computes the ILU(k,t) factorization of the local part of the
+!  This routine computes the ILU(k,t) factorization of the diagonal blocks of a
-!  matrix stored into a. This factorization is used to build the 'base
+!  distributed matrix. This factorization is used to build the 'base
 !  preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz
 !  preconditioner) corresponding to a certain level of a multilevel preconditioner.
 !
@@ -49,7 +49,7 @@
 !    Y. Saad, Iterative Methods for Sparse Linear Systems, Second Edition,
 !    SIAM, 2003, Chapter 10.
 !
-!  The local matrix to be factorized is stored into a and blck, as specified in
+!  The local matrix is stored into a and blck, as specified in
 !  the description of the arguments below. The storage format for both the L and
 !  U factors is CSR. The diagonal of the U factor is stored separately (actually,
 !  the inverse of the diagonal entries is stored; this is then managed in the solve
@@ -62,11 +62,11 @@
 !    thres   -  integer, input.
 !               The threshold t, i.e. the drop tolerance, in ILU(k,t).
 !    a       -  type(psb_dspmat_type), input.
-!               The sparse matrix structure containing the local matrix to be
+!               The sparse matrix structure containing the local matrix.
-!               factorized. Note that if the 'base' Additive Schwarz preconditioner
+!               Note that if the 'base' Additive Schwarz preconditioner
 !               has overlap greater than 0 and the matrix has not been reordered
-!               (see mld_bjac_bld), then a contains only the 'original' local part
+!               (see mld_fact_bld), then a contains only the 'original' local part
-!               of the matrix to be factorized, i.e. the rows of the matrix held
+!               of the distributed matrix, i.e. the rows of the matrix held
 !               by the calling process according to the initial data distribution.
 !    l       -  type(psb_dspmat_type), input/output.
 !               The L factor in the incomplete factorization.
@@ -85,10 +85,10 @@
 !               Error code.
 !    blck    -  type(psb_dspmat_type), input, optional, target.
 !               The sparse matrix structure containing the remote rows of the
-!               matrix to be factorized, that have been retrieved by mld_asmat_bld
+!               distributed matrix, that have been retrieved by mld_as_bld
 !               to build an Additive Schwarz base preconditioner with overlap
 !               greater than 0. If the overlap is 0 or the matrix has been reordered
-!               (see mld_bjac_bld), then blck does not contain any row.
+!               (see mld_fact_bld), then blck does not contain any row.
 !  
 subroutine mld_dilut_fact(fill_in,thres,a,l,u,d,info,blck)
   
@@ -203,8 +203,8 @@ contains
   ! Version:    real
   ! Note: internal subroutine of mld_dilut_fact
   !
-  !  This routine computes the ILU(k,t) factorization of the local part of the
+  !  This routine computes the ILU(k,t) factorization of the diagonal blocks of a
-  !  matrix stored into a. These factorization is used to build the 'base
+  !  distributed matrix. This factorization is used to build the 'base
   !  preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz
   !  preconditioner) corresponding to a certain level of a multilevel preconditioner.
   !
@@ -224,18 +224,18 @@ contains
   !               The total number of rows of the local matrix to be factorized,
   !               i.e. ma+mb.
   !    a       -  type(psb_dspmat_type), input.
-  !               The sparse matrix structure containing the local matrix to be
+  !               The sparse matrix structure containing the local matrix.
-  !               factorized. Note that, if the 'base' Additive Schwarz preconditioner
+  !               Note that, if the 'base' Additive Schwarz preconditioner
   !               has overlap greater than 0 and the matrix has not been reordered
-  !               (see mld_bjac_bld), then a contains only the 'original' local part
+  !               (see mld_fact_bld), then a contains only the 'original' local part
-  !               of the matrix to be factorized, i.e. the rows of the matrix held
+  !               of the distributed matrix, i.e. the rows of the matrix held
   !               by the calling process according to the initial data distribution.
   !    b       -  type(psb_dspmat_type), input.
   !               The sparse matrix structure containing the remote rows of the
-  !               matrix to be factorized, that have been retrieved by mld_asmat_bld
+  !               distributed matrix, that have been retrieved by mld_as_bld
   !               to build an Additive Schwarz base preconditioner with overlap
   !               greater than 0. If the overlap is 0 or the matrix has been reordered
-  !               (see mld_bjac_bld), then b does not contain   any row.
+  !               (see mld_fact_bld), then b does not contain any row.
   !    d       -  real(kind(1.d0)), dimension(:), output.
   !               The inverse of the diagonal entries of the U factor in the incomplete
   !               factorization.
@@ -666,8 +666,7 @@ contains
   !               Note: this argument is intent(inout) and not only intent(out)
   !               to retain its allocation, done by this routine.
   !
-  subroutine ilut_fact(thres,i,nrmi,row,heap,&
+  subroutine ilut_fact(thres,i,nrmi,row,heap,d,uia1,uia2,uaspk,nidx,idxs,info)
-       & d,uia1,uia2,uaspk,nidx,idxs,info)
 
     use psb_base_mod
 
@@ -787,7 +786,7 @@ contains
   !  - the array row is re-initialized for future use in mld_ilut_fact(see also
   !    ilut_copyin and ilut_fact).
   !
-  !  This routine is used by mld_dilut_factint in the computation of the      ILU(k,t)
+  !  This routine is used by mld_dilut_factint in the computation of the ILU(k,t)
   !  factorization of a local sparse matrix.
   !  
   !

mlprec/mld_dmlprec_aply.f90

@@ -49,15 +49,15 @@
 !  - X and Y are vectors,
 !  - alpha and beta are scalars.
 !
-!  For each level we have as many subdomains as processes (except for the coarsest
+!  For each level we have as many submatrices as processes (except for the coarsest
 !  level where we might have a replicated index space) and each process takes care
-!  of one subdomain.
+!  of one submatrix.
 !
 !  The multilevel preconditioner M is regarded as an array of 'base preconditioners',
 !  each representing the part of the preconditioner associated to a certain level.
 !  For each level ilev, the base preconditioner K(ilev) is stored in baseprecv(ilev)
 !  and is associated to a matrix A(ilev), obtained by 'tranferring' the original
-!  matrix A (i.e. the matrix to be preconditioned) to level ilev, through smoothed
+!  matrix A (i.e. the matrix to be preconditioned) to the level ilev, through smoothed
 !  aggregation.
 !
 !  The levels are numbered in increasing order starting from the finest one, i.e.
@@ -157,8 +157,8 @@
 !                 Error code.
 !
 !   Note that when the LU factorization of the matrix A(ilev) is computed instead of
-!   the ILU one, by using UMFPACK or SuperLU_dist, the corresponding L and U factors
+!   the ILU one, by using UMFPACK or SuperLU, the corresponding L and U factors
-!   are stored in data structures provided by UMFPACK or SuperLU_dist and pointed by
+!   are stored in data structures provided by UMFPACK or SuperLU and pointed by
 !   baseprecv(ilev)%iprcparm(mld_umf_ptr) or baseprecv(ilev)%iprcparm(mld_slu_ptr),
 !   respectively.
 !  
@@ -285,8 +285,45 @@ subroutine mld_dmlprec_aply(alpha,baseprecv,x,beta,y,desc_data,trans,work,info)
   return
 
 contains
-
+  !
+  ! Subroutine: add_ml_aply
+  ! Version:    real
+  ! Note: internal subroutine of mld_dmlprec_aply.
+  ! This routine computes
+  !  
+  !                        Y = beta*Y + alpha*op(M^(-1))*X,
+  !  where 
+  !  - M is a multilevel domain decomposition (Schwarz) preconditioner associated
+  !    to a certain matrix A and stored in the array baseprecv,
+  !  - op(M^(-1)) is M^(-1) or its transpose, according to the value of trans,
+  !  - X and Y are vectors,
+  !  - alpha and beta are scalars.
+  !
+  !  For each level we have as many submatrices as processes (except for the coarsest
+  !  level where we might have a replicated index space) and each process takes care
+  !  of one submatrix. 
+  !
+  !  The multilevel preconditioner M is regarded as an array of 'base preconditioners',
+  !  each representing the part of the preconditioner associated to a certain level.
+  !  For each level ilev, the base preconditioner K(ilev) is stored in baseprecv(ilev)
+  !  and is associated to a matrix A(ilev), obtained by 'tranferring' the original
+  !  matrix A (i.e. the matrix to be preconditioned) to the level ilev, through smoothed
+  !  aggregation.
+  !
+  !  The levels are numbered in increasing order starting from the finest one, i.e.
+  !  level 1 is the finest level and A(1) is the matrix A. 
+  !  This routine applies the multilevel preconditioner in an additive
+  !  way (additive through the levels and additive on the same level).
+  !  For details on the additive multilevel Schwarz preconditioner see
+  !  the Algorithm 3.1.1 in the book:
+  !    -  B.F. Smith, P.E. Bjorstad & W.D. Gropp,
+  !       Domain decomposition: parallel multilevel methods for elliptic partial
+  !       differential equations, Cambridge University Press, 1996.
+  !
+  !  For a detailed description of the arguments, see mld_dmlprec_aply.
+  !
   subroutine add_ml_aply(alpha,baseprecv,x,beta,y,desc_data,trans,work,info)
+    !
     implicit none 
     ! Arguments
     type(psb_desc_type),intent(in)      :: desc_data
@@ -329,39 +366,6 @@ contains
       call psb_errpush(4010,name,a_err='Allocate')
       goto 9999      
     end if
-
-    !
-    !       Additive multilevel
-    !
-    !   1. ! Apply the base preconditioner at level 1.
-    !      ! The sum over the subdomains is carried out in the
-    !      ! application of K(1).
-    !        X(1) = Xest
-    !        Y(1) = (K(1)^(-1))*X(1)
-    !
-    !    2.  DO ilev=2,nlev
-    !
-    !         ! Transfer X(ilev-1) to the next coarser level.
-    !           X(ilev) = AV(ilev; sm_pr_t_)*X(ilev-1)
-    !
-    !         ! Apply the base preconditioner at the current level.
-    !         ! The sum over the subdomains is carried out in the
-    !         ! application of K(ilev).
-    !           Y(ilev) = (K(ilev)^(-1))*X(ilev)
-    !
-    !        ENDDO
-    !
-    !    3.  DO ilev=nlev-1,1,-1
-    !
-    !         ! Transfer Y(ilev+1) to the next finer level.
-    !           Y(ilev) = AV(ilev+1; sm_pr_)*Y(ilev+1)
-    !
-    !        ENDDO
-    !     
-    !    4.  Yext = beta*Yext + alpha*Y(1)
-    !
-
-
     !
     ! STEP 1
     !
@@ -385,7 +389,6 @@ contains
       call psb_errpush(4010,name,a_err='baseprec_aply')
       goto 9999
     end if
-
     !
     ! STEP 2
     !
@@ -524,9 +527,46 @@ contains
     return
 
   end subroutine add_ml_aply
-
+  !
-
+  ! Subroutine: mlt_pre_ml_aply
+  ! Version:    real
+  ! Note: internal subroutine of mld_dmlprec_aply.
+  ! This routine computes
+  !  
+  !                        Y = beta*Y + alpha*op(M^(-1))*X,
+  !  where 
+  !  - M is a multilevel domain decomposition (Schwarz) preconditioner associated
+  !    to a certain matrix A and stored in the array baseprecv,
+  !  - op(M^(-1)) is M^(-1) or its transpose, according to the value of trans,
+  !  - X and Y are vectors,
+  !  - alpha and beta are scalars.
+  !
+  !  For each level we have as many submatrices as processes (except for the coarsest
+  !  level where we might have a replicated index space) and each process takes care
+  !  of one submatrix. 
+  !
+  !  The multilevel preconditioner M is regarded as an array of 'base preconditioners',
+  !  each representing the part of the preconditioner associated to a certain level.
+  !  For each level ilev, the base preconditioner K(ilev) is stored in baseprecv(ilev)
+  !  and is associated to a matrix A(ilev), obtained by 'tranferring' the original
+  !  matrix A (i.e. the matrix to be preconditioned) to the level ilev, through smoothed
+  !  aggregation.
+  !
+  !  The levels are numbered in increasing order starting from the finest one, i.e.
+  !  level 1 is the finest level and A(1) is the matrix A. 
+  !
+  !  This routine applies the multilevel preconditioner in a hybrid way
+  !  (multiplicative through the levels and additive on the same level)
+  !  and pre-smoothing.
+  !  For details on pre-smoothed hybrid multiplicative multilevel Schwarz preconditioner,
+  !  see the Algorithm 3.2.1 in the book:
+  !    -  B.F. Smith, P.E. Bjorstad & W.D. Gropp,
+  !       Domain decomposition: parallel multilevel methods for elliptic partial
+  !       differential equations, Cambridge University Press, 1996.
+  !
+  !  For a detailed description of the arguments, see mld_dmlprec_aply.
   subroutine mlt_pre_ml_aply(alpha,baseprecv,x,beta,y,desc_data,trans,work,info)
+    !
     implicit none 
     ! Arguments
     type(psb_desc_type),intent(in)      :: desc_data
@@ -570,43 +610,6 @@ contains
       goto 9999      
     end if
 
-    !
-    !    Pre-smoothing
-    !
-    !    1.   X(1) = Xext
-    !
-    !    2. ! Apply the base preconditioner at the finest level.
-    !         Y(1) = (K(1)^(-1))*X(1)
-    !
-    !    3. ! Compute the residual at the finest level.
-    !         TX(1) = X(1) - A(1)*Y(1)
-    !
-    !    4.   DO ilev=2, nlev
-    !
-    !          ! Transfer the residual to the current (coarser) level.
-    !            X(ilev) = AV(ilev; sm_pr_t_)*TX(ilev-1)
-    !
-    !          ! Apply the base preconditioner at the current level.
-    !          ! The sum over the subdomains is carried out in the
-    !          ! application of K(ilev).     
-    !            Y(ilev) = (K(ilev)^(-1))*X(ilev)
-    !
-    !          ! Compute the residual at the current level (except at
-    !          ! the coarsest level).
-    !            IF (ilev < nlev)
-    !               TX(ilev) = (X(ilev)-A(ilev)*Y(ilev))
-    !
-    !         ENDDO
-    !
-    !    5.   DO ilev=nlev-1,1,-1
-    !
-    !          ! Transfer Y(ilev+1) to the next finer level
-    !            Y(ilev) = Y(ilev) + AV(ilev+1; sm_pr_)*Y(ilev+1)
-    !
-    !         ENDDO
-    !     
-    !    6.  Yext = beta*Yext + alpha*Y(1)
-    ! 
 
     !
     ! STEP 1
@@ -800,9 +803,45 @@ contains
     end if
     return
   end subroutine mlt_pre_ml_aply
-
+  !
-
+  ! Subroutine: mlt_post_ml_aply
+  ! Version:    real
+  ! Note: internal subroutine of mld_dmlprec_aply.
+  ! This routine computes
+  !  
+  !                        Y = beta*Y + alpha*op(M^(-1))*X,
+  !  where 
+  !  - M is a multilevel domain decomposition (Schwarz) preconditioner associated
+  !    to a certain matrix A and stored in the array baseprecv,
+  !  - op(M^(-1)) is M^(-1) or its transpose, according to the value of trans,
+  !  - X and Y are vectors,
+  !  - alpha and beta are scalars.
+  !
+  !  For each level we have as many submatrices as processes (except for the coarsest
+  !  level where we might have a replicated index space) and each process takes care
+  !  of one submatrix. 
+  !
+  !  The multilevel preconditioner M is regarded as an array of 'base preconditioners',
+  !  each representing the part of the preconditioner associated to a certain level.
+  !  For each level ilev, the base preconditioner K(ilev) is stored in baseprecv(ilev)
+  !  and is associated to a matrix A(ilev), obtained by 'tranferring' the original
+  !  matrix A (i.e. the matrix to be preconditioned) to the level ilev, through smoothed
+  !  aggregation.
+  !
+  !  The levels are numbered in increasing order starting from the finest one, i.e.
+  !  level 1 is the finest level and A(1) is the matrix A. 
+  !
+  !  This routine applies the multilevel preconditioner in a hybrid way
+  !  (multiplicative through the levels and additive on the same level)
+  !  and post-smoothing.
+  !  For details on hybrid multiplicative multilevel Schwarz preconditioners, see
+  !    -  B.F. Smith, P.E. Bjorstad & W.D. Gropp,
+  !       Domain decomposition: parallel multilevel methods for elliptic partial
+  !       differential equations, Cambridge University Press, 1996.
+  !
+  !  For a detailed description of the arguments, see mld_dmlprec_aply.
   subroutine mlt_post_ml_aply(alpha,baseprecv,x,beta,y,desc_data,trans,work,info)
+    !
     implicit none 
     ! Arguments
     type(psb_desc_type),intent(in)      :: desc_data
@@ -845,37 +884,6 @@ contains
       call psb_errpush(4010,name,a_err='Allocate')
       goto 9999      
     end if
-
-    !
-    !    Post-smoothing
-    ! 
-    !    1.  X(1) = Xext
-    !
-    !    2.  DO ilev=2, nlev
-    !
-    !         ! Transfer X(ilev-1) to the next coarser level.
-    !           X(ilev) = AV(ilev; sm_pr_t_)*X(ilev-1) 
-    !
-    !        ENDDO
-    !   
-    !    3.! Apply the preconditioner at the coarsest level.
-    !        Y(nlev) = (K(nlev)^(-1))*X(nlev)
-    !
-    !    4.  DO ilev=nlev-1,1,-1
-    !
-    !         ! Transfer Y(ilev+1) to the next finer level.
-    !           Y(ilev) = AV(ilev+1; sm_pr_)*Y(ilev+1)
-    !
-    !         ! Compute the residual at the current level and apply to it the
-    !         ! base preconditioner. The sum over the subdomains is carried out
-    !         ! in the application of K(ilev).
-    !           Y(ilev) = Y(ilev) + (K(ilev)^(-1))*(X(ilev)-A(ilev)*Y(ilev))
-    !
-    !        ENDDO
-    !
-    !    5.  Yext = beta*Yext + alpha*Y(1)
-    ! 
-
     !
     ! STEP 1
     !
@@ -1091,9 +1099,47 @@ contains
     end if
     return
   end subroutine mlt_post_ml_aply
-
+  !
-
+  ! Subroutine: mlt_twoside_ml_aply
+  ! Version:    real
+  ! Note: internal subroutine of mld_dmlprec_aply.
+  ! This routine computes
+  !  
+  !                        Y = beta*Y + alpha*op(M^(-1))*X,
+  !  where 
+  !  - M is a multilevel domain decomposition (Schwarz) preconditioner associated
+  !    to a certain matrix A and stored in the array baseprecv,
+  !  - op(M^(-1)) is M^(-1) or its transpose, according to the value of trans,
+  !  - X and Y are vectors,               
+  !  - alpha and beta are scalars.
+  !
+  !  For each level we have as many submatrices as processes (except for the coarsest
+  !  level where we might have a replicated index space) and each process takes care
+  !  of one submatrix.   
+  !
+  !  The multilevel preconditioner M is regarded as an array of 'base preconditioners',
+  !  each representing the part of the preconditioner associated to a certain level.
+  !  For each level ilev, the base preconditioner K(ilev) is stored in baseprecv(ilev)
+  !  and is associated to a matrix A(ilev), obtained by 'tranferring' the original
+  !  matrix A (i.e. the matrix to be preconditioned) to the level ilev, through smoothed
+  !  aggregation.
+  !
+  !  The levels are numbered in increasing order starting from the finest one, i.e.
+  !  level 1 is the finest level and A(1) is the matrix A. 
+  !
+  !  This routine applies the multilevel preconditioner in a symmetrized hybrid way
+  !  (multiplicative through the levels and additive on the same level, with pre and 
+  !  post-smoothing).
+  !  For details on the symmetrized hybrid multiplicative multilevel Schwarz
+  !  preconditioners, see the Algorithm 3.2.2 of the book:
+  !    -  B.F. Smith, P.E. Bjorstad & W.D. Gropp,
+  !       Domain decomposition: parallel multilevel methods for elliptic partial
+  !       differential equations, Cambridge University Press, 1996.
+  !
+  !  For a detailed description of the arguments, see mld_dmlprec_aply.
+  !
   subroutine mlt_twoside_ml_aply(alpha,baseprecv,x,beta,y,desc_data,trans,work,info)
+    !
     implicit none 
     ! Arguments
     type(psb_desc_type),intent(in)      :: desc_data
@@ -1136,49 +1182,6 @@ contains
       call psb_errpush(4010,name,a_err='Allocate')
       goto 9999      
     end if
-
-    !
-    !    Pre- and post-smoothing (symmetrized)
-    ! 
-    !    1.   X(1)  = Xext
-    !
-    !    2. ! Apply the base peconditioner at the finest level
-    !         Y(1)  = (K(1)^(-1))*X(1)
-    !
-    !    3. ! Compute the residual at the finest level
-    !         TX(1) = X(1) - A(1)*Y(1)
-    !
-    !    4.   DO ilev=2, nlev
-    !
-    !          ! Transfer the residual to the current (coarser) level
-    !            X(ilev) = AV(ilev; sm_pr_t)*TX(ilev-1)
-    !    
-    !          ! Apply the base preconditioner at the current level.
-    !          ! The sum over the subdomains is carried out in the
-    !          ! application of K(ilev)
-    !            Y(ilev) = (K(ilev)^(-1))*X(ilev)
-    !
-    !          ! Compute the residual at the current level
-    !            TX(ilev) = (X(ilev)-A(ilev)*Y(ilev))
-    !
-    !         ENDDO
-    !
-    !    5.   DO ilev=NLEV-1,1,-1
-    !
-    !          ! Transfer Y(ilev+1) to the next finer level
-    !            Y(ilev) = Y(ilev) + AV(ilev+1; sm_pr_)*Y(ilev+1)
-    !
-    !          ! Compute the residual at the current level and apply to it the
-    !          ! base preconditioner. The sum over the subdomains is carried out
-    !          ! in the application of K(ilev)     
-    !            Y(ilev) = Y(ilev) + (K(ilev)**(-1))*(X(ilev)-A(ilev)*Y(ilev))
-    !
-    !         ENDDO
-    !
-    !    6.  Yext = beta*Yext + alpha*Y(1)
-    !
-
-    !
     ! STEP 1
     !
     ! Copy the input vector X

mlprec/mld_dprec_aply.f90

@@ -141,7 +141,7 @@ subroutine mld_dprec_aply(prec,x,y,desc_data,info,trans,work)
   endif
 
   ! If the original distribution has an overlap we should fix that. 
-  call psb_ovrl(y,desc_data,info,update=psb_avg_)
+  call psb_halo(y,desc_data,info,data=psb_comm_mov_)
 
 
   if (present(work)) then 

mlprec/mld_dprecinit.f90

@@ -210,7 +210,7 @@ subroutine mld_dprecinit(p,ptype,info,nlev)
       p%baseprecv(ilev_)%iprcparm(mld_n_ovr_)         = 0
       p%baseprecv(ilev_)%iprcparm(mld_ml_type_)       = mld_mult_ml_
       p%baseprecv(ilev_)%iprcparm(mld_aggr_alg_)      = mld_dec_aggr_
-      p%baseprecv(ilev_)%iprcparm(mld_aggr_kind_)   = mld_smooth_prol_
+      p%baseprecv(ilev_)%iprcparm(mld_aggr_kind_)     = mld_smooth_prol_
       p%baseprecv(ilev_)%iprcparm(mld_coarse_mat_)    = mld_distr_mat_
       p%baseprecv(ilev_)%iprcparm(mld_smooth_pos_)    = mld_post_smooth_
       p%baseprecv(ilev_)%iprcparm(mld_aggr_eig_)      = mld_max_norm_

mlprec/mld_dprecset.f90

@@ -58,7 +58,7 @@
 !               numbers, as reported in MLD2P4 user's guide.
 !    val     -  integer, input.
 !               The value of the parameter to be set. The list of allowed
-!               values is reported in MLD2P4 user's      guide.
+!               values is reported in MLD2P4 user's guide.
 !    info    -  integer, output.
 !               Error code.
 !    ilev    -  integer, optional, input.
@@ -276,7 +276,7 @@ subroutine mld_dprecsetc(p,what,string,info,ilev)
 
   implicit none
 
-! Arguments
+  ! Arguments
   type(mld_dprec_type), intent(inout)    :: p
   integer, intent(in)                    :: what 
   character(len=*), intent(in)           :: string
@@ -527,7 +527,7 @@ subroutine mld_dprecsetd(p,what,val,info,ilev)
 
   implicit none
 
-! Arguments
+  ! Arguments
   type(mld_dprec_type), intent(inout)    :: p
   integer, intent(in)                    :: what 
   real(kind(1.d0)), intent(in)           :: val

mlprec/mld_dsp_renum.f90

@@ -50,7 +50,7 @@
 !  description of the arguments below.
 !
 !  If required by the user (p%iprcparm(mld_sub_ren_) /= 0), the routine is
-!  used by mld_bjac_bld in building the block-Jacobi and Additive Schwarz 
+!  used by mld_fact_bld in building the block-Jacobi and Additive Schwarz 
 !  'base preconditioners' corresponding to any level of a multilevel
 !  preconditioner.
 !  
@@ -63,7 +63,7 @@
 !               distribution.
 !    blck    -  type(psb_dspmat_type), input.
 !               The sparse matrix structure containing the remote rows of the
-!               matrix to be reordered, that have been retrieved by mld_asmat_bld
+!               matrix to be reordered, that have been retrieved by mld_as_bld
 !               to build an Additive Schwarz base preconditioner with overlap
 !               greater than 0.If the overlap is 0, then blck does not contain
 !               any row.

mlprec/mld_dsub_aply.f90

@@ -81,29 +81,28 @@
 !     K^(-1), alpha = 1 and beta = 0.
 !
 !  The block-Jacobi preconditioner or solver and the L and U factors of the LU
-!  or ILU factorizations have been built by the routine mld_dbjac_bld and stored
+!  or ILU factorizations have been built by the routine mld_fact_bld and stored
-!  into the 'base preconditioner' data structure prec. See mld_dbjac_bld for more
+!  into the 'base preconditioner' data structure prec. See mld_fact_bld for more
 !  details.
 !
-!  This routine is used by mld_dbaseprec_aply, to apply a 'base' block-Jacobi or
+!  This routine is used by mld_as_aply, to apply a 'base' block-Jacobi or
 !  Additive Schwarz (AS) preconditioner at any level of a multilevel preconditioner,
 !  or a block-Jacobi or LU or ILU solver at the coarsest level of a multilevel
 !  preconditioner. 
 !
-!  Inside mld_dbaseprec_aply, tasks 1, 3 and 4 may be selected if
+!  Tasks 1, 3 and 4 are selected when prec%iprcparm(smooth_sweeps_) = 1, 
-!  prec%iprcparm(smooth_sweeps_) = 1, while task 2 if prec%iprcparm(smooth_sweeps_)
+!  while task 2 is selected when prec%iprcparm(smooth_sweeps_) > 1. Furthermore
-!   > 1. Furthermore, tasks 1, 2 and 3 may be performed if the matrix A is
+!  Tasks 1, 2 and 3 may be performed when the matrix A is
 !  distributed among the processes (prec%iprcparm(mld_coarse_mat_) = mld_distr_mat_),
-!  while task 4 may be performed if A is replicated on the processes
+!  while task 4 may be performed when A is replicated on the processes
 !  (prec%iprcparm(mld_coarse_mat_) = mld_repl_mat_). Note that the matrix A is
 !  distributed among the processes at each level of the multilevel preconditioner,
 !  except the coarsest one, where it may be either distributed or replicated on
-!  the processes. Furthermore, the tasks 2, 3 and 4 are performed only at the
+!  the processes.  Tasks 2, 3 and 4 are performed only at the coarsest level.
-!  coarsest level. Note also that this routine manages implicitly the fact that
+!  Note also that this routine manages implicitly the fact that
 !  the matrix is distributed or replicated, i.e. it does not make any explicit
 !  reference to the value of prec%iprcparm(mld_coarse_mat_).
 !
-!
 ! Arguments:
 !
 !   alpha      -  real(kind(0.d0)), input.
@@ -207,9 +206,7 @@ subroutine mld_dsub_aply(alpha,prec,x,beta,y,desc_data,trans,work,info)
     endif
     
   else if (prec%iprcparm(mld_smooth_sweeps_) > 1) then 
-
     !
-    ! TASK 2
     !
     ! Apply prec%iprcparm(smooth_sweeps_) sweeps of a block-Jacobi solver
     ! to compute an approximate solution of a linear system.

mlprec/mld_dsub_solve.f90

@@ -44,11 +44,14 @@
 !                       Y = beta*Y + alpha*op(K^(-1))*X,
 !
 !  where
-!  - K is a factored  matrix, as specified below,
+!  - K is a factored matrix, as specified below,
 !  - op(K^(-1)) is K^(-1) or its transpose, according to the value of trans,
 !  - X and Y are vectors,
 !  - alpha and beta are scalars.
 !
+!  Depending on K, alpha, beta (and on the communication descriptor desc_data
+!  - see the arguments below), the above computation may correspond to one of
+!  the following tasks:
 !
 !  1. Solution of a linear system with sparse factors LU generated by means
 !     of an incomplete factorization approximating 
@@ -58,7 +61,7 @@
 !     they are also block-diagonal) or replicated. 
 !
 !  2. Solution of a linear system with sparse factors LU generated by means
-!     of an complete factorization 
+!     of a complete factorization 
 !
 !                                    A*Y = X,
 !
@@ -70,6 +73,11 @@
 !     and block diagonal or replicated; in case c. the matrix A and its
 !     factors are distributed.
 !
+!  This routine is used by mld_dsub_aply, to apply a 'base' block-Jacobi or
+!  Additive Schwarz (AS) preconditioner at any level of a multilevel preconditioner,
+!  or a block-Jacobi or LU or ILU solver at the coarsest level of a multilevel
+!  preconditioner. 
+!
 !
 ! Arguments:
 !

mlprec/mld_zas_bld.f90

@@ -41,7 +41,9 @@
 !
 !  This routine builds the Additive Schwarz (AS) preconditioner.
 !  If the preconditioner is the block-Jacobi one, the routine makes only a copy of
-!  the descriptor of the original matrix.
+!  the descriptor of the original matrix and then proceeds to call mld_fact_bld
+!  for LU or incomplete LU factorization of the diagonal blocks of the
+!  distributed matrix.
 !    
 !
 ! Arguments:
@@ -69,7 +71,6 @@ subroutine mld_zas_bld(a,desc_a,p,upd,info)
 
   Implicit None
 
-  ! Arguments
   ! Arguments
   type(psb_zspmat_type), intent(in), target :: a
   Type(psb_desc_type), Intent(in)           :: desc_a 

mlprec/mld_zbaseprec_bld.f90

@@ -154,32 +154,8 @@ subroutine mld_zbaseprc_bld(a,desc_a,p,info,upd)
       goto 9999
     end if
 
-  case(mld_bjac_)
+  case(mld_bjac_,mld_as_)
-
+    ! Additive Schwarz preconditioners/smoothers
-    call mld_check_def(p%iprcparm(mld_sub_ren_),'renumbering',&
-         &  mld_renum_none_,is_legal_renum)
-    call mld_check_def(p%iprcparm(mld_sub_solve_),'fact',&
-         &  mld_ilu_n_,is_legal_ml_fact)
-
-    call psb_cdcpy(desc_a,p%desc_data,info)
-    if(info /= 0) then
-      info=4010
-      ch_err='psb_cdcpy'
-      call psb_errpush(info,name,a_err=ch_err)
-      goto 9999
-    end if
-
-    ! Build the local part of the base preconditioner
-    call mld_fact_bld(a,p,iupd,info)
-    if(info /= 0) then
-      info=4010
-      call psb_errpush(info,name,a_err='mld_fact_bld')
-      goto 9999
-    end if
-
-
-  case(mld_as_)
-    ! Block Jacobi and additive Schwarz preconditioners/smoothers
 
     call mld_check_def(p%iprcparm(mld_n_ovr_),'overlap',&
          &  0,is_legal_n_ovr)
@@ -202,7 +178,7 @@ subroutine mld_zbaseprc_bld(a,desc_a,p,info,upd)
          & write(debug_unit,*) me,' ',trim(name),&
          & ': Calling mld_as_bld'
 
-    ! Build the local part of the base preconditioner
+    ! Build the local part of the base preconditioner/smoother
     call mld_as_bld(a,desc_a,p,iupd,info)
     if(info /= 0) then
       info=4010

mlprec/mld_zfact_bld.f90

@@ -39,34 +39,35 @@
 ! Subroutine: mld_zfact_bld
 ! Version:    complex
 !
-!  This routine computes an LU or incomplete LU factorization of the input
+!  This routine computes an LU or incomplete LU factorization of the diagonal blocks
-!  matrix, according to the value of p%iprcparm(iprcparm(sub_solve_),
+!  of a distributed matrix, according to the value of p%iprcparm(iprcparm(sub_solve_), 
 !  set by the user through mld_dprecinit or mld_dprecset.
-!  It may also split the local matrix into its block-diagonal and
+!  It may also split the matrix into its block-diagonal and
 !  off block-diagonal parts, for the future application of multiple
 !  block-Jacobi sweeps.
 !
-!  This routine is used by mld_dbaseprec_bld, to build a 'base' block-Jacobi or
+!  This routine is used by mld_as_bld, to build a 'base' block-Jacobi or
 !  Additive Schwarz (AS) preconditioner at any level of a multilevel preconditioner,
 !  or a block-Jacobi or LU or ILU solver at the coarsest level of a multilevel
 !  preconditioner. For the Additive Schwarz, it is called from mld_as_bld,
 !  which prepares the overlap descriptor and retrieves the remote rows into blck.
 !
-!  More precisely, the routine  performs one of the following tasks: 
+!  More precisely, the routine performs one of the following tasks: 
 !
-!  1. construction of a block-Jacobi preconditioner associated
+!  1. LU or ILU factorization of the diagonal blocks of the distributed matrix
-!     to a matrix A distributed among the processes (allowed at any level);
+!     for the construction of a block-Jacobi or AS preconditioners
+!     (allowed at any level);
 !
 !  2. setup of block-Jacobi sweeps to compute an approximate solution of a
 !     linear system
 !                                    A*Y = X,
 !     distributed among the processes (allowed only at the coarsest level);
 !
-!  3. LU factorization of a linear system
+!  3. LU factorization of the matrix of a linear system
 !                                    A*Y = X,
 !     distributed among the processes (allowed only at the coarsest level);
 !
-!  4. LU or incomplete LU factorization of a linear system
+!  4. LU or incomplete LU factorization of the matrix of a linear system
 !                                    A*Y = X,
 !     replicated on the processes (allowed only at the coarsest level).
 !
@@ -84,7 +85,7 @@
 ! Arguments:
 !    a       -  type(psb_zspmat_type), input.
 !               The sparse matrix structure containing the local part of the
-!               matrix to be preconditioned or factorized.
+!               distributed matrix.
 !    p       -  type(mld_zbaseprec_type), input/output.
 !               The 'base preconditioner' data structure containing the local 
 !               part of the preconditioner or solver at the current level.
@@ -99,9 +100,9 @@
 !               the new preconditioner.
 !    blck    -  type(psb_zspmat_type), input, optional.
 !               The sparse matrix structure containing the remote rows of the
-!               matrix to be factorized, that have been retrieved by mld_as_bld
+!               distributed matrix, that have been retrieved by mld_as_bld
 !               to build an Additive Schwarz base preconditioner with overlap
-!               greater than 0.  If the overlap is 0 blck is empty.
+!               greater than 0. If the overlap is 0 blck is empty.
 !  
 subroutine mld_zfact_bld(a,p,upd,info,blck)
 
@@ -291,8 +292,6 @@ subroutine mld_zfact_bld(a,p,upd,info,blck)
     ! No reordering of the local matrix is required
     !
   case(0)
-
-
     !
     ! In case of multiple block-Jacobi sweeps, clip into p%av(ap_nd_)
     ! the off block-diagonal part of the local extended matrix. The
@@ -334,7 +333,6 @@ subroutine mld_zfact_bld(a,p,upd,info,blck)
         goto 9999
       end if
     end if
-
     ! 
     ! Compute a factorization of the diagonal block of the local matrix,
     ! according to the choice made by the user by setting p%iprcparm(sub_solve_)

mlprec/mld_zilu0_fact.f90

@@ -41,20 +41,20 @@
 ! Contains:   mld_zilu0_factint, ilu_copyin
 !
 !  This routine computes either the ILU(0) or the MILU(0) factorization of the
-!  local part of the matrix stored into a. These factorizations are used to
+!  diagonal blocks of a distributed matrix. These factorizations 
-!  build the 'base preconditioner' (block-Jacobi preconditioner/solver, Additive
+!  are used to build the 'base preconditioner' (block-Jacobi preconditioner/solver, 
-!  Schwarz preconditioner) corresponding to a certain level of a multilevel
+!  Additive Schwarz preconditioner) corresponding to a given level of a multilevel
 !  preconditioner.
 !
 !  Details on the above factorizations can be found in
 !    Y. Saad, Iterative Methods for Sparse Linear Systems, Second Edition,
 !    SIAM, 2003, Chapter 10.
 !
-!  The local matrix to be factorized is stored into a and blck, as specified
+!  The local matrix is stored into a and blck, as specified in the description 
-!  in the description of the arguments below. The storage format for both the
+!  of the arguments below. The storage format for both the L and U factors is CSR. 
-!  L and U factors is CSR. The diagonal of the U factor is stored separately
+!  The diagonal of the U factor is stored separately (actually, the inverse of the 
-!  (actually, the inverse of the diagonal entries is stored; this is then
+!  diagonal entries is stored; this is then managed in the solve stage associated 
-!  managed in the solve stage associated to the ILU(0)/MILU(0) factorization).
+!  to the ILU(0)/MILU(0) factorization).
 !
 !  The routine copies and factors "on the fly" from a and blck into l (L factor),
 !  u (U factor, except its diagonal) and d (diagonal of U).
@@ -69,11 +69,11 @@
 !               The MILU(0) factorization is computed if ialg = 2 (= mld_milu_n_);
 !               the ILU(0) factorization otherwise.
 !    a       -  type(psb_zspmat_type), input.
-!               The sparse matrix structure containing the local matrix to be
+!               The sparse matrix structure containing the local matrix.
-!               factorized. Note that if the 'base' Additive Schwarz preconditioner
+!               Note that if the 'base' Additive Schwarz preconditioner
 !               has overlap greater than 0 and the matrix has not been reordered
-!               (see mld_bjac_bld), then a contains     only the 'original' local part
+!               (see mld_as_bld), then a contains only the 'original' local part
-!               of the matrix to be factorized, i.e. the rows of the matrix held
+!               of the distributed matrix, i.e. the rows of the matrix held
 !               by the calling process according to the initial data distribution.
 !    l       -  type(psb_zspmat_type), input/output.
 !               The L factor in the incomplete factorization.
@@ -92,15 +92,16 @@
 !               Error code.
 !    blck    -  type(psb_zspmat_type), input, optional, target.
 !               The sparse matrix structure containing the remote rows of the
-!               matrix to be factorized, that have been retrieved by mld_asmat_bld
+!               distributed matrix, that have been retrieved by mld_as_bld
 !               to build an Additive Schwarz base preconditioner with overlap
 !               greater than 0. If the overlap is 0 or the matrix has been reordered
-!               (see mld_bjac_bld), then blck is empty.
+!               (see mld_fact_bld), then blck is empty.
 !  
 subroutine mld_zilu0_fact(ialg,a,l,u,d,info,blck)
 
   use psb_base_mod
   use mld_inner_mod, mld_protect_name => mld_zilu0_fact
+
   implicit none
 
   ! Arguments
@@ -202,14 +203,15 @@ contains
   !
   ! Subroutine: mld_zilu0_factint
   ! Version:    complex
-  ! Note: internal subroutine of mld_zilu0_fact
+  ! Note: internal subroutine of mld_zilu0_fact.
   !
-  !  This routine computes either the ILU(0) or the MILU(0) factorization of the
+  !  This routine computes either the ILU(0) or the MILU(0) factorization of the 
-  !  local part of the matrix stored into a. These factorizations are used to build
+  !  diagonal blocks of a distributed matrix. 
-  !  the 'base preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz
+  !  These factorizations are used to build the 'base preconditioner' 
-  !  preconditioner) corresponding to a certain level of a multilevel preconditioner.
+  !  (block-Jacobi preconditioner/solver, Additive Schwarz
+  !  preconditioner) corresponding to a given level of a multilevel preconditioner.
   !
-  !  The local matrix to be factorized is stored into a and b, as specified in the
+  !  The local matrix is stored into a and b, as specified in the
   !  description of the arguments below. The storage format for both the L and U
   !  factors is CSR. The diagonal of the U factor is stored separately (actually,
   !  the inverse of the diagonal entries is stored; this is then managed in the
@@ -222,28 +224,29 @@ contains
   ! Arguments:
   !    ialg    -  integer, input.
   !               The type of incomplete factorization to be performed.
-  !               The MILU(0) factorization is computed if ialg = 2 (= mld_milu_n_);
+  !               The ILU(0) factorization is computed if ialg = 1 (= mld_ilu_n_),
-  !               the ILU(0) factorization otherwise.
+  !               the MILU(0) one if ialg = 2 (= mld_milu_n_); other values
+  !               are not allowed.
   !    m       -  integer, output.
   !               The total number of rows of the local matrix to be factorized,
   !               i.e. ma+mb.
   !    ma      -  integer, input
   !               The number of rows of the local submatrix stored into a.
   !    a       -  type(psb_zspmat_type), input.
-  !               The sparse matrix structure containing the local matrix to be
+  !               The sparse matrix structure containing the local matrix.
-  !               factorized. Note that, if the 'base' Additive Schwarz preconditioner
+  !               Note that, if the 'base' Additive Schwarz preconditioner
   !               has overlap greater than 0 and the matrix has not been reordered
-  !               (see mld_bjac_bld), then a contains only the 'original' local part
+  !               (see mld_fact_bld), then a contains only the 'original' local part
-  !               of the matrix to be factorized, i.e. the rows of the matrix held
+  !               of the distributed matrix, i.e. the rows of the matrix held
   !               by the calling process according to the initial data distribution.
   !    mb      -  integer, input.
   !               The number of rows of the local submatrix stored into b.
   !    b       -  type(psb_zspmat_type), input.
   !               The sparse matrix structure containing the remote rows of the
-  !               matrix to be factorized, that have been retrieved by mld_asmat_bld
+  !               distributed matrix, that have been retrieved by mld_as_bld
   !               to build an Additive Schwarz base preconditioner with overlap
   !               greater than 0. If the overlap is 0 or the matrix has been
-  !               reordered (see mld_bjac_bld), then b does not contain any row.
+  !               reordered (see mld_fact_bld), then b does not contain any row.
   !    d       -  complex(kind(1.d0)), dimension(:), output.
   !               The inverse of the diagonal entries of the U factor in the
   !               incomplete factorization.
@@ -484,7 +487,7 @@ contains
   !  copied into laspk, dia, uaspk row by row, through successive calls to
   !  ilu_copyin.
   !
-  !  The routine is used by mld_zilu0_factin in the computation of the ILU(0)/MILU(0)
+  !  The routine is used by mld_zilu0_factint in the computation of the ILU(0)/MILU(0)
   !  factorization of a local sparse matrix.
   !  
   !  TODO: modify the routine to allow copying into output L and U that are

mlprec/mld_zilu_bld.f90

@@ -39,9 +39,9 @@
 ! Subroutine: mld_zilu_bld
 ! Version:    complex
 !
-!  This routine computes an incomplete LU (ILU) factorization of the local part
+!  This routine computes an incomplete LU (ILU) factorization of the diagonal blocks
-!  of the matrix stored into a. This factorization is used to build the 'base
+!  of a distributed matrix. This factorization is used to build 
-!  preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz
+!  the 'base preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz
 !  preconditioner) corresponding to a certain level of a multilevel preconditioner.
 !  The following factorizations are available:
 !  - ILU(k), i.e. ILU factorization with fill-in level k,
@@ -62,12 +62,12 @@
 !
 ! Arguments:
 !    a       -  type(psb_zspmat_type), input.
-!               The sparse matrix structure containing the local matrix to be
+!               The sparse matrix structure containing the local matrix.
-!               factorized. Note that if p%iprcparm(mld_n_ovr_) > 0, i.e. the
+!               Note that if p%iprcparm(mld_n_ovr_) > 0, i.e. the
 !               'base' Additive Schwarz preconditioner has overlap greater than
-!               0, and p%iprcparm(mld_sub_ren_) = 0, i.e. a      reordering of the
+!               0, and p%iprcparm(mld_sub_ren_) = 0, i.e. a reordering of the
-!               matrix has not been performed (see mld_bjac_bld), then a contains
+!               matrix has not been performed (see mld_fact_bld), then a contains
-!               only the 'original' local part of the matrix to      be factorized,
+!               only the 'original' local part of the distributed matrix,
 !               i.e. the rows of the matrix held by the calling process according
 !               to the initial data distribution.
 !    p       -  type(mld_zbaseprc_type), input/output.
@@ -81,10 +81,10 @@
 !               Error code.
 !    blck    -  type(psb_zspmat_type), input, optional.
 !               The sparse matrix structure containing the remote rows of the
-!               matrix to be factorized, that have been retrieved by mld_asmat_bld
+!               distributed matrix, that have been retrieved by mld_as_bld
 !               to build an Additive Schwarz base preconditioner with overlap
 !               greater than 0. If the overlap is 0 or the matrix has been reordered
-!               (see mld_bjac_bld), then blck does not contain any row.
+!               (see mld_fact_bld), then blck does not contain any row.
 !
 subroutine mld_zilu_bld(a,p,upd,info,blck)
 
@@ -272,7 +272,6 @@ subroutine mld_zilu_bld(a,p,upd,info,blck)
   end if
   return
 
-
 end subroutine mld_zilu_bld
 
 

mlprec/mld_ziluk_fact.f90

@@ -41,16 +41,16 @@
 ! Contains:   mld_ziluk_factint, iluk_copyin, iluk_fact, iluk_copyout
 !
 !  This routine computes either the ILU(k) or the MILU(k) factorization of the
-!  local part of the matrix stored into a. These factorizations are used to
+!  diagonal blocks of a distributed matrix. These factorizations are used to build 
-!  build the 'base preconditioner' (block-Jacobi preconditioner/solver, Additive
+!  the 'base preconditioner' (block-Jacobi preconditioner/solver, 
-!  Schwarz preconditioner) corresponding to a certain level of a multilevel
+!  Additive Schwarz preconditioner) corresponding to a certain level of a multilevel
 !  preconditioner.
 !
 !  Details on the above factorizations can be found in
 !    Y. Saad, Iterative Methods for Sparse Linear Systems, Second Edition,
 !    SIAM, 2003, Chapter 10.
 !
-!  The local matrix to be factorized is stored into a and blck, as specified in
+!  The local matrix is stored into a and blck, as specified in
 !  the description of the arguments below. The storage format for both the L and
 !  U factors is CSR. The diagonal of the U factor is stored separately (actually,
 !  the inverse of the diagonal entries is stored; this is then managed in the solve
@@ -62,14 +62,15 @@
 !               The fill-in level k in ILU(k)/MILU(k).
 !    ialg    -  integer, input.
 !               The type of incomplete factorization to be performed.
-!               The MILU(k) factorization is computed if ialg = 2 (= mld_milu_n_);
+!               The ILU(k) factorization is computed if ialg = 1 (= mld_ilu_n_);
-!               the ILU(k) factorization otherwise.
+!               the MILU(k) one if ialg = 2 (= mld_milu_n_); other values are
+!               not allowed.
 !    a       -  type(psb_zspmat_type), input.
-!               The sparse matrix structure containing the local matrix to be
+!               The sparse matrix structure containing the local matrix.
-!               factorized. Note that if the 'base' Additive Schwarz preconditioner
+!               Note that if the 'base' Additive Schwarz preconditioner
 !               has overlap greater than 0 and the matrix has not been reordered
-!               (see mld_bjac_bld), then a contains only the 'original' local part
+!               (see mld_fact_bld), then a contains only the 'original' local part
-!               of the matrix to be factorized, i.e. the rows of the matrix held
+!               of the distributed matrix, i.e. the rows of the matrix held
 !               by the calling process according to the initial data distribution.
 !    l       -  type(psb_zspmat_type), input/output.
 !               The L factor in the incomplete factorization.
@@ -88,15 +89,16 @@
 !               Error code.
 !    blck    -  type(psb_zspmat_type), input, optional, target.
 !               The sparse matrix structure containing the remote rows of the
-!               matrix to be factorized, that have been retrieved by mld_asmat_bld
+!               distributed matrix, that have been retrieved by mld_as_bld
 !               to build an Additive Schwarz base preconditioner with overlap
 !               greater than 0. If the overlap is 0 or the matrix has been reordered
-!               (see mld_bjac_bld), then blck does not contain any row.
+!               (see mld_fact_bld), then blck does not contain any row.
 !  
 subroutine mld_ziluk_fact(fill_in,ialg,a,l,u,d,info,blck)
 
   use psb_base_mod
   use mld_inner_mod, mld_protect_name => mld_ziluk_fact
+
   implicit none
 
   ! Arguments
@@ -199,11 +201,11 @@ contains
   ! Note: internal subroutine of mld_ziluk_fact
   !
   !  This routine computes either the ILU(k) or the MILU(k) factorization of the
-  !  local part of the matrix stored into a. These factorizations are used to build
+  !  diagonal blocks of a distributed matrix. These factorizations are used to build
   !  the 'base preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz
   !  preconditioner) corresponding to a certain level of a multilevel preconditioner.
   !
-  !  The local matrix to be factorized is stored into a and b, as specified in the
+  !  The local matrix is stored into a and b, as specified in the
   !  description of the arguments below. The storage format for both the L and U
   !  factors is CSR. The diagonal of the U factor is stored separately (actually,
   !  the inverse of the diagonal entries is stored; this is then managed in the
@@ -221,18 +223,18 @@ contains
   !               The total number of rows of the local matrix to be factorized,
   !               i.e. ma+mb.
   !    a       -  type(psb_zspmat_type), input.
-  !               The sparse matrix structure containing the local matrix to be
+  !               The sparse matrix structure containing the local matrix.
-  !               factorized. Note that, if the 'base' Additive Schwarz preconditioner
+  !               Note that, if the 'base' Additive Schwarz preconditioner
   !               has overlap greater than 0 and the matrix has not been reordered
-  !               (see mld_bjac_bld), then a contains only the 'original' local part
+  !               (see mld_fact_bld), then a contains only the 'original' local part
-  !               of the matrix to be factorized, i.e. the rows of the matrix held
+  !               of the distributed matrix, i.e. the rows of the matrix held
   !               by the calling process according to the initial data distribution.
   !    b       -  type(psb_zspmat_type), input.
   !               The sparse matrix structure containing the remote rows of the
-  !               matrix to be factorized, that have been retrieved by mld_asmat_bld
+  !               distributed matrix, that have been retrieved by mld_as_bld
   !               to build an Additive Schwarz base preconditioner with overlap
   !               greater than 0. If the overlap is 0 or the matrix has been reordered
-  !               (see mld_bjac_bld), then b does not contain   any row.
+  !               (see mld_fact_bld), then b does not contain   any row.
   !    d       -  complex(kind(1.d0)), dimension(:), output.
   !               The inverse of the diagonal entries of the U factor in the incomplete
   !               factorization.

mlprec/mld_zilut_fact.f90

@@ -40,8 +40,8 @@
 ! Version:    real
 ! Contains:   mld_zilut_factint, ilut_copyin, ilut_fact, ilut_copyout
 !
-!  This routine computes the ILU(k,t) factorization of the local part of the
+!  This routine computes the ILU(k,t) factorization of the diagonal blocks of a
-!  matrix stored into a. This factorization is used to build the 'base
+!  distributed matrix. This factorization is used to build the 'base
 !  preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz
 !  preconditioner) corresponding to a certain level of a multilevel preconditioner.
 !
@@ -49,7 +49,7 @@
 !    Y. Saad, Iterative Methods for Sparse Linear Systems, Second Edition,
 !    SIAM, 2003, Chapter 10.
 !
-!  The local matrix to be factorized is stored into a and blck, as specified in
+!  The local matrix is stored into a and blck, as specified in
 !  the description of the arguments below. The storage format for both the L and
 !  U factors is CSR. The diagonal of the U factor is stored separately (actually,
 !  the inverse of the diagonal entries is stored; this is then managed in the solve
@@ -62,11 +62,11 @@
 !    thres   -  integer, input.
 !               The threshold t, i.e. the drop tolerance, in ILU(k,t).
 !    a       -  type(psb_zspmat_type), input.
-!               The sparse matrix structure containing the local matrix to be
+!               The sparse matrix structure containing the local matrix.
-!               factorized. Note that if the 'base' Additive Schwarz preconditioner
+!               Note that if the 'base' Additive Schwarz preconditioner
 !               has overlap greater than 0 and the matrix has not been reordered
-!               (see mld_bjac_bld), then a contains only the 'original' local part
+!               (see mld_fact_bld), then a contains only the 'original' local part
-!               of the matrix to be factorized, i.e. the rows of the matrix held
+!               of the distributed matrix, i.e. the rows of the matrix held
 !               by the calling process according to the initial data distribution.
 !    l       -  type(psb_zspmat_type), input/output.
 !               The L factor in the incomplete factorization.
@@ -85,15 +85,16 @@
 !               Error code.
 !    blck    -  type(psb_zspmat_type), input, optional, target.
 !               The sparse matrix structure containing the remote rows of the
-!               matrix to be factorized, that have been retrieved by mld_asmat_bld
+!               distributed matrix, that have been retrieved by mld_as_bld
 !               to build an Additive Schwarz base preconditioner with overlap
 !               greater than 0. If the overlap is 0 or the matrix has been reordered
-!               (see mld_bjac_bld), then blck does not contain any row.
+!               (see mld_fact_bld), then blck does not contain any row.
 !  
 subroutine mld_zilut_fact(fill_in,thres,a,l,u,d,info,blck)
   
   use psb_base_mod
   use mld_inner_mod, mld_protect_name => mld_zilut_fact
+
   implicit none
 
   ! Arguments
@@ -202,8 +203,8 @@ contains
   ! Version:    real
   ! Note: internal subroutine of mld_zilut_fact
   !
-  !  This routine computes the ILU(k,t) factorization of the local part of the
+  !  This routine computes the ILU(k,t) factorization of the diagonal blocks of a
-  !  matrix stored into a. These factorization is used to build the 'base
+  !  distributed matrix. This factorization is used to build the 'base
   !  preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz
   !  preconditioner) corresponding to a certain level of a multilevel preconditioner.
   !
@@ -223,18 +224,18 @@ contains
   !               The total number of rows of the local matrix to be factorized,
   !               i.e. ma+mb.
   !    a       -  type(psb_zspmat_type), input.
-  !               The sparse matrix structure containing the local matrix to be
+  !               The sparse matrix structure containing the local matrix.
-  !               factorized. Note that, if the 'base' Additive Schwarz preconditioner
+  !               Note that, if the 'base' Additive Schwarz preconditioner
   !               has overlap greater than 0 and the matrix has not been reordered
-  !               (see mld_bjac_bld), then a contains only the 'original' local part
+  !               (see mld_fact_bld), then a contains only the 'original' local part
-  !               of the matrix to be factorized, i.e. the rows of the matrix held
+  !               of the distributed matrix, i.e. the rows of the matrix held
   !               by the calling process according to the initial data distribution.
   !    b       -  type(psb_zspmat_type), input.
   !               The sparse matrix structure containing the remote rows of the
-  !               matrix to be factorized, that have been retrieved by mld_asmat_bld
+  !               distributed matrix, that have been retrieved by mld_as_bld
   !               to build an Additive Schwarz base preconditioner with overlap
   !               greater than 0. If the overlap is 0 or the matrix has been reordered
-  !               (see mld_bjac_bld), then b does not contain   any row.
+  !               (see mld_fact_bld), then b does not contain   any row.
   !    d       -  complex(kind(1.d0)), dimension(:), output.
   !               The inverse of the diagonal entries of the U factor in the incomplete
   !               factorization.
@@ -286,6 +287,7 @@ contains
     type(psb_int_heap) :: heap
     type(psb_zspmat_type) :: trw
     character(len=20), parameter  :: name='mld_zilut_factint'
+    character(len=20)             :: ch_err
 
     if (psb_get_errstatus() /= 0) return 
     info = 0
@@ -785,7 +787,7 @@ contains
   !  - the array row is re-initialized for future use in mld_ilut_fact(see also
   !    ilut_copyin and ilut_fact).
   !
-  !  This routine is used by mld_zilut_factint in the computation of the      ILU(k,t)
+  !  This routine is used by mld_zilut_factint in the computation of the ILU(k,t)
   !  factorization of a local sparse matrix.
   !  
   !

mlprec/mld_zmlprec_aply.f90

@@ -49,15 +49,15 @@
 !  - X and Y are vectors,
 !  - alpha and beta are scalars.
 !
-!  For each level we have as many subdomains as processes (except for the coarsest
+!  For each level we have as many submatrices as processes (except for the coarsest
 !  level where we might have a replicated index space) and each process takes care
-!  of one subdomain.
+!  of one submatrix.
 !
 !  The multilevel preconditioner M is regarded as an array of 'base preconditioners',
 !  each representing the part of the preconditioner associated to a certain level.
 !  For each level ilev, the base preconditioner K(ilev) is stored in baseprecv(ilev)
 !  and is associated to a matrix A(ilev), obtained by 'tranferring' the original
-!  matrix A (i.e. the matrix to be preconditioned) to level ilev, through smoothed
+!  matrix A (i.e. the matrix to be preconditioned) to the level ilev, through smoothed
 !  aggregation.
 !
 !  The levels are numbered in increasing order starting from the finest one, i.e.
@@ -157,8 +157,8 @@
 !                 Error code.
 !
 !   Note that when the LU factorization of the matrix A(ilev) is computed instead of
-!   the ILU one, by using UMFPACK or SuperLU_dist, the corresponding L and U factors
+!   the ILU one, by using UMFPACK or SuperLU, the corresponding L and U factors
-!   are stored in data structures provided by UMFPACK or SuperLU_dist and pointed by
+!   are stored in data structures provided by UMFPACK or SuperLU and pointed by
 !   baseprecv(ilev)%iprcparm(mld_umf_ptr) or baseprecv(ilev)%iprcparm(mld_slu_ptr),
 !   respectively.
 !  
@@ -285,7 +285,44 @@ subroutine mld_zmlprec_aply(alpha,baseprecv,x,beta,y,desc_data,trans,work,info)
   return
 
 contains
-
+  !
+  ! Subroutine: add_ml_aply
+  ! Version:    complex
+  ! Note: internal subroutine of mld_dmlprec_aply.
+  ! This routine computes
+  !  
+  !                        Y = beta*Y + alpha*op(M^(-1))*X,
+  !  where 
+  !  - M is a multilevel domain decomposition (Schwarz) preconditioner associated
+  !    to a certain matrix A and stored in the array baseprecv,
+  !  - op(M^(-1)) is M^(-1) or its (conjugate) transpose, according to
+  !    the value of trans,
+  !  - X and Y are vectors,
+  !  - alpha and beta are scalars.
+  !
+  !  For each level we have as many submatrices as processes (except for the coarsest
+  !  level where we might have a replicated index space) and each process takes care
+  !  of one submatrix. 
+  !
+  !  The multilevel preconditioner M is regarded as an array of 'base preconditioners',
+  !  each representing the part of the preconditioner associated to a certain level.
+  !  For each level ilev, the base preconditioner K(ilev) is stored in baseprecv(ilev)
+  !  and is associated to a matrix A(ilev), obtained by 'tranferring' the original
+  !  matrix A (i.e. the matrix to be preconditioned) to the level ilev, through smoothed
+  !  aggregation.
+  !
+  !  The levels are numbered in increasing order starting from the finest one, i.e.
+  !  level 1 is the finest level and A(1) is the matrix A. 
+  !  This routine applies the multilevel preconditioner in an additive
+  !  way (additive through the levels and additive on the same level).
+  !  For details on the additive multilevel Schwarz preconditioner see
+  !  the Algorithm 3.1.1 in the book:
+  !    -  B.F. Smith, P.E. Bjorstad & W.D. Gropp,
+  !       Domain decomposition: parallel multilevel methods for elliptic partial
+  !       differential equations, Cambridge University Press, 1996.
+  !
+  !  For a detailed description of the arguments, see mld_dmlprec_aply.
+  !
   subroutine add_ml_aply(alpha,baseprecv,x,beta,y,desc_data,trans,work,info)
     implicit none 
     ! Arguments
@@ -329,39 +366,6 @@ contains
       call psb_errpush(4010,name,a_err='Allocate')
       goto 9999      
     end if
-
-    !
-    !       Additive multilevel
-    !
-    !   1. ! Apply the base preconditioner at level 1.
-    !      ! The sum over the subdomains is carried out in the
-    !      ! application of K(1).
-    !        X(1) = Xest
-    !        Y(1) = (K(1)^(-1))*X(1)
-    !
-    !    2.  DO ilev=2,nlev
-    !
-    !         ! Transfer X(ilev-1) to the next coarser level.
-    !           X(ilev) = AV(ilev; sm_pr_t_)*X(ilev-1)
-    !
-    !         ! Apply the base preconditioner at the current level.
-    !         ! The sum over the subdomains is carried out in the
-    !         ! application of K(ilev).
-    !           Y(ilev) = (K(ilev)^(-1))*X(ilev)
-    !
-    !        ENDDO
-    !
-    !    3.  DO ilev=nlev-1,1,-1
-    !
-    !         ! Transfer Y(ilev+1) to the next finer level.
-    !           Y(ilev) = AV(ilev+1; sm_pr_)*Y(ilev+1)
-    !
-    !        ENDDO
-    !     
-    !    4.  Yext = beta*Yext + alpha*Y(1)
-    !
-
-
     !
     ! STEP 1
     !
@@ -385,7 +389,6 @@ contains
       call psb_errpush(4010,name,a_err='baseprec_aply')
       goto 9999
     end if
-
     !
     ! STEP 2
     !
@@ -524,9 +527,47 @@ contains
     return
 
   end subroutine add_ml_aply
-
+  !
-
+  ! Subroutine: mlt_pre_ml_aply
+  ! Version:    complex
+  ! Note: internal subroutine of mld_dmlprec_aply.
+  ! This routine computes
+  !  
+  !                        Y = beta*Y + alpha*op(M^(-1))*X,
+  !  where 
+  !  - M is a multilevel domain decomposition (Schwarz) preconditioner associated
+  !    to a certain matrix A and stored in the array baseprecv,
+  !  - op(M^(-1)) is M^(-1) or its (conjugate) transpose, according to
+  !    the value of trans,
+  !  - X and Y are vectors,
+  !  - alpha and beta are scalars.
+  !
+  !  For each level we have as many submatrices as processes (except for the coarsest
+  !  level where we might have a replicated index space) and each process takes care
+  !  of one submatrix. 
+  !
+  !  The multilevel preconditioner M is regarded as an array of 'base preconditioners',
+  !  each representing the part of the preconditioner associated to a certain level.
+  !  For each level ilev, the base preconditioner K(ilev) is stored in baseprecv(ilev)
+  !  and is associated to a matrix A(ilev), obtained by 'tranferring' the original
+  !  matrix A (i.e. the matrix to be preconditioned) to the level ilev, through smoothed
+  !  aggregation.
+  !
+  !  The levels are numbered in increasing order starting from the finest one, i.e.
+  !  level 1 is the finest level and A(1) is the matrix A. 
+  !
+  !  This routine applies the multilevel preconditioner in a hybrid way
+  !  (multiplicative through the levels and additive on the same level)
+  !  and pre-smoothing.
+  !  For details on pre-smoothed hybrid multiplicative multilevel Schwarz preconditioner,
+  !  see the Algorithm 3.2.1 in the book:
+  !    -  B.F. Smith, P.E. Bjorstad & W.D. Gropp,
+  !       Domain decomposition: parallel multilevel methods for elliptic partial
+  !       differential equations, Cambridge University Press, 1996.
+  !
+  !  For a detailed description of the arguments, see mld_dmlprec_aply.
   subroutine mlt_pre_ml_aply(alpha,baseprecv,x,beta,y,desc_data,trans,work,info)
+    !
     implicit none 
     ! Arguments
     type(psb_desc_type),intent(in)      :: desc_data
@@ -570,43 +611,6 @@ contains
       goto 9999      
     end if
 
-    !
-    !    Pre-smoothing
-    !
-    !    1.   X(1) = Xext
-    !
-    !    2. ! Apply the base preconditioner at the finest level.
-    !         Y(1) = (K(1)^(-1))*X(1)
-    !
-    !    3. ! Compute the residual at the finest level.
-    !         TX(1) = X(1) - A(1)*Y(1)
-    !
-    !    4.   DO ilev=2, nlev
-    !
-    !          ! Transfer the residual to the current (coarser) level.
-    !            X(ilev) = AV(ilev; sm_pr_t_)*TX(ilev-1)
-    !
-    !          ! Apply the base preconditioner at the current level.
-    !          ! The sum over the subdomains is carried out in the
-    !          ! application of K(ilev).     
-    !            Y(ilev) = (K(ilev)^(-1))*X(ilev)
-    !
-    !          ! Compute the residual at the current level (except at
-    !          ! the coarsest level).
-    !            IF (ilev < nlev)
-    !               TX(ilev) = (X(ilev)-A(ilev)*Y(ilev))
-    !
-    !         ENDDO
-    !
-    !    5.   DO ilev=nlev-1,1,-1
-    !
-    !          ! Transfer Y(ilev+1) to the next finer level
-    !            Y(ilev) = Y(ilev) + AV(ilev+1; sm_pr_)*Y(ilev+1)
-    !
-    !         ENDDO
-    !     
-    !    6.  Yext = beta*Yext + alpha*Y(1)
-    ! 
 
     !
     ! STEP 1
@@ -800,9 +804,46 @@ contains
     end if
     return
   end subroutine mlt_pre_ml_aply
-
+  !
-
+  ! Subroutine: mlt_post_ml_aply
+  ! Version:    complex
+  ! Note: internal subroutine of mld_dmlprec_aply.
+  ! This routine computes
+  !  
+  !                        Y = beta*Y + alpha*op(M^(-1))*X,
+  !  where 
+  !  - M is a multilevel domain decomposition (Schwarz) preconditioner associated
+  !    to a certain matrix A and stored in the array baseprecv,
+  !  - op(M^(-1)) is M^(-1) or its (conjugate) transpose, according to
+  !    the value of trans,
+  !  - X and Y are vectors,
+  !  - alpha and beta are scalars.
+  !
+  !  For each level we have as many submatrices as processes (except for the coarsest
+  !  level where we might have a replicated index space) and each process takes care
+  !  of one submatrix. 
+  !
+  !  The multilevel preconditioner M is regarded as an array of 'base preconditioners',
+  !  each representing the part of the preconditioner associated to a certain level.
+  !  For each level ilev, the base preconditioner K(ilev) is stored in baseprecv(ilev)
+  !  and is associated to a matrix A(ilev), obtained by 'tranferring' the original
+  !  matrix A (i.e. the matrix to be preconditioned) to the level ilev, through smoothed
+  !  aggregation.
+  !
+  !  The levels are numbered in increasing order starting from the finest one, i.e.
+  !  level 1 is the finest level and A(1) is the matrix A. 
+  !
+  !  This routine applies the multilevel preconditioner in a hybrid way
+  !  (multiplicative through the levels and additive on the same level)
+  !  and post-smoothing.
+  !  For details on hybrid multiplicative multilevel Schwarz preconditioners, see
+  !    -  B.F. Smith, P.E. Bjorstad & W.D. Gropp,
+  !       Domain decomposition: parallel multilevel methods for elliptic partial
+  !       differential equations, Cambridge University Press, 1996.
+  !
+  !  For a detailed description of the arguments, see mld_dmlprec_aply.
   subroutine mlt_post_ml_aply(alpha,baseprecv,x,beta,y,desc_data,trans,work,info)
+    !
     implicit none 
     ! Arguments
     type(psb_desc_type),intent(in)      :: desc_data
@@ -845,37 +886,6 @@ contains
       call psb_errpush(4010,name,a_err='Allocate')
       goto 9999      
     end if
-
-    !
-    !    Post-smoothing
-    ! 
-    !    1.  X(1) = Xext
-    !
-    !    2.  DO ilev=2, nlev
-    !
-    !         ! Transfer X(ilev-1) to the next coarser level.
-    !           X(ilev) = AV(ilev; sm_pr_t_)*X(ilev-1) 
-    !
-    !        ENDDO
-    !   
-    !    3.! Apply the preconditioner at the coarsest level.
-    !        Y(nlev) = (K(nlev)^(-1))*X(nlev)
-    !
-    !    4.  DO ilev=nlev-1,1,-1
-    !
-    !         ! Transfer Y(ilev+1) to the next finer level.
-    !           Y(ilev) = AV(ilev+1; sm_pr_)*Y(ilev+1)
-    !
-    !         ! Compute the residual at the current level and apply to it the
-    !         ! base preconditioner. The sum over the subdomains is carried out
-    !         ! in the application of K(ilev).
-    !           Y(ilev) = Y(ilev) + (K(ilev)^(-1))*(X(ilev)-A(ilev)*Y(ilev))
-    !
-    !        ENDDO
-    !
-    !    5.  Yext = beta*Yext + alpha*Y(1)
-    ! 
-
     !
     ! STEP 1
     !
@@ -1090,9 +1100,48 @@ contains
     end if
     return
   end subroutine mlt_post_ml_aply
-
+  !
-
+  ! Subroutine: mlt_twoside_ml_aply
+  ! Version:    complex
+  ! Note: internal subroutine of mld_dmlprec_aply.
+  ! This routine computes
+  !  
+  !                        Y = beta*Y + alpha*op(M^(-1))*X,
+  !  where 
+  !  - M is a multilevel domain decomposition (Schwarz) preconditioner associated
+  !    to a certain matrix A and stored in the array baseprecv,
+  !  - op(M^(-1)) is M^(-1) or its (conjugate) transpose, according to
+  !    the value of trans,
+  !  - X and Y are vectors,               
+  !  - alpha and beta are scalars.
+  !
+  !  For each level we have as many submatrices as processes (except for the coarsest
+  !  level where we might have a replicated index space) and each process takes care
+  !  of one submatrix.   
+  !
+  !  The multilevel preconditioner M is regarded as an array of 'base preconditioners',
+  !  each representing the part of the preconditioner associated to a certain level.
+  !  For each level ilev, the base preconditioner K(ilev) is stored in baseprecv(ilev)
+  !  and is associated to a matrix A(ilev), obtained by 'tranferring' the original
+  !  matrix A (i.e. the matrix to be preconditioned) to the level ilev, through smoothed
+  !  aggregation.
+  !
+  !  The levels are numbered in increasing order starting from the finest one, i.e.
+  !  level 1 is the finest level and A(1) is the matrix A. 
+  !
+  !  This routine applies the multilevel preconditioner in a symmetrized hybrid way
+  !  (multiplicative through the levels and additive on the same level, with pre and 
+  !  post-smoothing).
+  !  For details on the symmetrized hybrid multiplicative multilevel Schwarz
+  !  preconditioners, see the Algorithm 3.2.2 of the book:
+  !    -  B.F. Smith, P.E. Bjorstad & W.D. Gropp,
+  !       Domain decomposition: parallel multilevel methods for elliptic partial
+  !       differential equations, Cambridge University Press, 1996.
+  !
+  !  For a detailed description of the arguments, see mld_dmlprec_aply.
+  !
   subroutine mlt_twoside_ml_aply(alpha,baseprecv,x,beta,y,desc_data,trans,work,info)
+    !
     implicit none 
     ! Arguments
     type(psb_desc_type),intent(in)      :: desc_data
@@ -1135,49 +1184,6 @@ contains
       call psb_errpush(4010,name,a_err='Allocate')
       goto 9999      
     end if
-
-    !
-    !    Pre- and post-smoothing (symmetrized)
-    ! 
-    !    1.   X(1)  = Xext
-    !
-    !    2. ! Apply the base peconditioner at the finest level
-    !         Y(1)  = (K(1)^(-1))*X(1)
-    !
-    !    3. ! Compute the residual at the finest level
-    !         TX(1) = X(1) - A(1)*Y(1)
-    !
-    !    4.   DO ilev=2, nlev
-    !
-    !          ! Transfer the residual to the current (coarser) level
-    !            X(ilev) = AV(ilev; sm_pr_t)*TX(ilev-1)
-    !    
-    !          ! Apply the base preconditioner at the current level.
-    !          ! The sum over the subdomains is carried out in the
-    !          ! application of K(ilev)
-    !            Y(ilev) = (K(ilev)^(-1))*X(ilev)
-    !
-    !          ! Compute the residual at the current level
-    !            TX(ilev) = (X(ilev)-A(ilev)*Y(ilev))
-    !
-    !         ENDDO
-    !
-    !    5.   DO ilev=NLEV-1,1,-1
-    !
-    !          ! Transfer Y(ilev+1) to the next finer level
-    !            Y(ilev) = Y(ilev) + AV(ilev+1; sm_pr_)*Y(ilev+1)
-    !
-    !          ! Compute the residual at the current level and apply to it the
-    !          ! base preconditioner. The sum over the subdomains is carried out
-    !          ! in the application of K(ilev)     
-    !            Y(ilev) = Y(ilev) + (K(ilev)**(-1))*(X(ilev)-A(ilev)*Y(ilev))
-    !
-    !         ENDDO
-    !
-    !    6.  Yext = beta*Yext + alpha*Y(1)
-    !
-
-    !
     ! STEP 1
     !
     ! Copy the input vector X

mlprec/mld_zprec_aply.f90

@@ -141,7 +141,8 @@ subroutine mld_zprec_aply(prec,x,y,desc_data,info,trans,work)
   endif
 
   ! If the original distribution has an overlap we should fix that. 
-  call psb_ovrl(y,desc_data,info,update=psb_avg_)
+  call psb_halo(y,desc_data,info,data=psb_comm_mov_)
+
 
   if (present(work)) then 
   else

mlprec/mld_zprecinit.f90

@@ -210,7 +210,7 @@ subroutine mld_zprecinit(p,ptype,info,nlev)
       p%baseprecv(ilev_)%iprcparm(mld_n_ovr_)         = 0
       p%baseprecv(ilev_)%iprcparm(mld_ml_type_)       = mld_mult_ml_
       p%baseprecv(ilev_)%iprcparm(mld_aggr_alg_)      = mld_dec_aggr_
-      p%baseprecv(ilev_)%iprcparm(mld_aggr_kind_)   = mld_smooth_prol_
+      p%baseprecv(ilev_)%iprcparm(mld_aggr_kind_)     = mld_smooth_prol_
       p%baseprecv(ilev_)%iprcparm(mld_coarse_mat_)    = mld_distr_mat_
       p%baseprecv(ilev_)%iprcparm(mld_smooth_pos_)    = mld_post_smooth_
       p%baseprecv(ilev_)%iprcparm(mld_aggr_eig_)      = mld_max_norm_

mlprec/mld_zprecset.f90

@@ -58,7 +58,7 @@
 !               numbers, as reported in MLD2P4 user's guide.
 !    val     -  integer, input.
 !               The value of the parameter to be set. The list of allowed
-!               values is reported in MLD2P4 user's      guide.
+!               values is reported in MLD2P4 user's guide.
 !    info    -  integer, output.
 !               Error code.
 !    ilev    -  integer, optional, input.
@@ -275,6 +275,8 @@ subroutine mld_zprecsetc(p,what,string,info,ilev)
   use mld_prec_mod, mld_protect_name => mld_zprecsetc
 
   implicit none
+
+  ! Arguments
   type(mld_zprec_type), intent(inout)    :: p
   integer, intent(in)                    :: what 
   character(len=*), intent(in)           :: string
@@ -524,6 +526,8 @@ subroutine mld_zprecsetd(p,what,val,info,ilev)
   use mld_prec_mod, mld_protect_name => mld_zprecsetd
 
   implicit none
+
+  ! Arguments
   type(mld_zprec_type), intent(inout)    :: p
   integer, intent(in)                    :: what 
   real(kind(1.d0)), intent(in)           :: val

mlprec/mld_zsp_renum.f90

@@ -50,7 +50,7 @@
 !  description of the arguments below.
 !
 !  If required by the user (p%iprcparm(mld_sub_ren_) /= 0), the routine is
-!  used by mld_bjac_bld in building the block-Jacobi and Additive Schwarz 
+!  used by mld_fact_bld in building the block-Jacobi and Additive Schwarz 
 !  'base preconditioners' corresponding to any level of a multilevel
 !  preconditioner.
 !  
@@ -63,7 +63,7 @@
 !               distribution.
 !    blck    -  type(psb_zspmat_type), input.
 !               The sparse matrix structure containing the remote rows of the
-!               matrix to be reordered, that have been retrieved by mld_asmat_bld
+!               matrix to be reordered, that have been retrieved by mld_as_bld
 !               to build an Additive Schwarz base preconditioner with overlap
 !               greater than 0.If the overlap is 0, then blck does not contain
 !               any row.

mlprec/mld_zsub_aply.f90

@@ -81,29 +81,28 @@
 !     K^(-1), alpha = 1 and beta = 0.
 !
 !  The block-Jacobi preconditioner or solver and the L and U factors of the LU
-!  or ILU factorizations have been built by the routine mld_dbjac_bld and stored
+!  or ILU factorizations have been built by the routine mld_fact_bld and stored
-!  into the 'base preconditioner' data structure prec. See mld_dbjac_bld for more
+!  into the 'base preconditioner' data structure prec. See mld_fact_bld for more
 !  details.
 !
-!  This routine is used by mld_dbaseprec_aply, to apply a 'base' block-Jacobi or
+!  This routine is used by mld_as_aply, to apply a 'base' block-Jacobi or
 !  Additive Schwarz (AS) preconditioner at any level of a multilevel preconditioner,
 !  or a block-Jacobi or LU or ILU solver at the coarsest level of a multilevel
 !  preconditioner. 
 !
-!  Inside mld_dbaseprec_aply, tasks 1, 3 and 4 may be selected if
+!  Tasks 1, 3 and 4 are selected when prec%iprcparm(smooth_sweeps_) = 1, 
-!  prec%iprcparm(smooth_sweeps_) = 1, while task 2 if prec%iprcparm(smooth_sweeps_)
+!  while task 2 is selected when prec%iprcparm(smooth_sweeps_) > 1. Furthermore
-!   > 1. Furthermore, tasks 1, 2 and 3 may be performed if the matrix A is
+!  Tasks 1, 2 and 3 may be performed when the matrix A is
 !  distributed among the processes (prec%iprcparm(mld_coarse_mat_) = mld_distr_mat_),
-!  while task 4 may be performed if A is replicated on the processes
+!  while task 4 may be performed when A is replicated on the processes
 !  (prec%iprcparm(mld_coarse_mat_) = mld_repl_mat_). Note that the matrix A is
 !  distributed among the processes at each level of the multilevel preconditioner,
 !  except the coarsest one, where it may be either distributed or replicated on
-!  the processes. Furthermore, the tasks 2, 3 and 4 are performed only at the
+!  the processes.  Tasks 2, 3 and 4 are performed only at the coarsest level.
-!  coarsest level. Note also that this routine manages implicitly the fact that
+!  Note also that this routine manages implicitly the fact that
 !  the matrix is distributed or replicated, i.e. it does not make any explicit
 !  reference to the value of prec%iprcparm(mld_coarse_mat_).
 !
-!
 ! Arguments:
 !
 !   alpha      -  complex(kind(0.d0)), input.
@@ -208,9 +207,7 @@ subroutine mld_zsub_aply(alpha,prec,x,beta,y,desc_data,trans,work,info)
     endif
     
   else if (prec%iprcparm(mld_smooth_sweeps_) > 1) then 
-
     !
-    ! TASK 2
     !
     ! Apply prec%iprcparm(smooth_sweeps_) sweeps of a block-Jacobi solver
     ! to compute an approximate solution of a linear system.

mlprec/mld_zsub_solve.f90

@@ -44,11 +44,14 @@
 !                       Y = beta*Y + alpha*op(K^(-1))*X,
 !
 !  where
-!  - K is a factored  matrix, as specified below,
+!  - K is a factored matrix, as specified below,
 !  - op(K^(-1)) is K^(-1) or its transpose, according to the value of trans,
 !  - X and Y are vectors,
 !  - alpha and beta are scalars.
 !
+!  Depending on K, alpha, beta (and on the communication descriptor desc_data
+!  - see the arguments below), the above computation may correspond to one of
+!  the following tasks:
 !
 !  1. Solution of a linear system with sparse factors LU generated by means
 !     of an incomplete factorization approximating 
@@ -58,7 +61,7 @@
 !     they are also block-diagonal) or replicated. 
 !
 !  2. Solution of a linear system with sparse factors LU generated by means
-!     of an complete factorization 
+!     of a complete factorization 
 !
 !                                    A*Y = X,
 !
@@ -70,6 +73,11 @@
 !     and block diagonal or replicated; in case c. the matrix A and its
 !     factors are distributed.
 !
+!  This routine is used by mld_dsub_aply, to apply a 'base' block-Jacobi or
+!  Additive Schwarz (AS) preconditioner at any level of a multilevel preconditioner,
+!  or a block-Jacobi or LU or ILU solver at the coarsest level of a multilevel
+!  preconditioner. 
+!
 !
 ! Arguments:
 !