From e5535835ec9fff44a82cc3931805a61fea28afc1 Mon Sep 17 00:00:00 2001
From: Salvatore Filippone <salvatore.filippone@cranfield.ac.uk>
Date: Sun, 31 Mar 2019 12:01:19 +0100
Subject: [PATCH] Implement clean_zeros for CSC and CSR

---
 base/modules/serial/psb_c_csc_mat_mod.f90 | 33 +++++++++++-
 base/modules/serial/psb_c_csr_mat_mod.f90 | 29 +++++++++++
 base/modules/serial/psb_d_csc_mat_mod.f90 | 33 +++++++++++-
 base/modules/serial/psb_d_csr_mat_mod.f90 | 29 +++++++++++
 base/modules/serial/psb_s_csc_mat_mod.f90 | 33 +++++++++++-
 base/modules/serial/psb_s_csr_mat_mod.f90 | 29 +++++++++++
 base/modules/serial/psb_z_csc_mat_mod.f90 | 33 +++++++++++-
 base/modules/serial/psb_z_csr_mat_mod.f90 | 29 +++++++++++
 base/serial/impl/psb_c_csc_impl.f90       | 60 +++++++++++++++++++++-
 base/serial/impl/psb_c_csr_impl.f90       | 61 +++++++++++++++++++++++
 base/serial/impl/psb_d_csc_impl.f90       | 60 +++++++++++++++++++++-
 base/serial/impl/psb_d_csr_impl.f90       | 61 +++++++++++++++++++++++
 base/serial/impl/psb_s_csc_impl.f90       | 60 +++++++++++++++++++++-
 base/serial/impl/psb_s_csr_impl.f90       | 61 +++++++++++++++++++++++
 base/serial/impl/psb_z_csc_impl.f90       | 60 +++++++++++++++++++++-
 base/serial/impl/psb_z_csr_impl.f90       | 61 +++++++++++++++++++++++
 16 files changed, 720 insertions(+), 12 deletions(-)

diff --git a/base/modules/serial/psb_c_csc_mat_mod.f90 b/base/modules/serial/psb_c_csc_mat_mod.f90
index 47256546..62f79c7b 100644
--- a/base/modules/serial/psb_c_csc_mat_mod.f90
+++ b/base/modules/serial/psb_c_csc_mat_mod.f90
@@ -87,6 +87,7 @@ module psb_c_csc_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_c_mv_csc_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_c_mv_csc_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_c_mv_csc_from_fmt
+    procedure, pass(a) :: clean_zeros => psb_c_csc_clean_zeros
     procedure, pass(a) :: csput_a      => psb_c_csc_csput_a
     procedure, pass(a) :: get_diag    => psb_c_csc_get_diag
     procedure, pass(a) :: csgetptn    => psb_c_csc_csgetptn
@@ -142,10 +143,11 @@ module psb_c_csc_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_lc_mv_csc_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_lc_mv_csc_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_lc_mv_csc_from_fmt
-    procedure, pass(a) :: csput_a      => psb_lc_csc_csput_a
+    procedure, pass(a) :: clean_zeros => psb_lc_csc_clean_zeros
+    procedure, pass(a) :: csput_a     => psb_lc_csc_csput_a
     procedure, pass(a) :: get_diag    => psb_lc_csc_get_diag
     procedure, pass(a) :: csgetptn    => psb_lc_csc_csgetptn
-    procedure, pass(a) :: csgetrow   => psb_lc_csc_csgetrow
+    procedure, pass(a) :: csgetrow    => psb_lc_csc_csgetrow
     procedure, pass(a) :: get_nz_col  => lc_csc_get_nz_col
     procedure, pass(a) :: reinit      => psb_lc_csc_reinit
     procedure, pass(a) :: trim        => psb_lc_csc_trim
@@ -311,6 +313,20 @@ module psb_c_csc_mat_mod
     end subroutine psb_c_mv_csc_from_fmt
   end interface
   
+  !
+  !> 
+  !! \memberof  psb_c_csc_sparse_mat
+  !! \see psb_c_base_mat_mod::psb_c_base_clean_zeros
+  !
+  interface
+    subroutine  psb_c_csc_clean_zeros(a, info)
+      import 
+      class(psb_c_csc_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_c_csc_clean_zeros
+  end interface
+  
+  
   !> \memberof psb_c_csc_sparse_mat
   !! \see psb_c_base_mat_mod::psb_c_base_cp_from
   interface 
@@ -702,6 +718,19 @@ module psb_c_csc_mat_mod
     end subroutine psb_lc_mv_csc_from_fmt
   end interface
   
+  !
+  !> 
+  !! \memberof  psb_lc_csc_sparse_mat
+  !! \see psb_lc_base_mat_mod::psb_lc_base_clean_zeros
+  !
+  interface
+    subroutine  psb_lc_csc_clean_zeros(a, info)
+      import 
+      class(psb_lc_csc_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_lc_csc_clean_zeros
+  end interface
+  
   !> \memberof psb_lc_csc_sparse_mat
   !! \see psb_lc_base_mat_mod::psb_lc_base_cp_from
   interface 
diff --git a/base/modules/serial/psb_c_csr_mat_mod.f90 b/base/modules/serial/psb_c_csr_mat_mod.f90
index 9d72a770..5e502eba 100644
--- a/base/modules/serial/psb_c_csr_mat_mod.f90
+++ b/base/modules/serial/psb_c_csr_mat_mod.f90
@@ -1,3 +1,4 @@
+
 !   
 !                Parallel Sparse BLAS  version 3.5
 !      (C) Copyright 2006-2018
@@ -90,6 +91,7 @@ module psb_c_csr_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_c_mv_csr_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_c_mv_csr_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_c_mv_csr_from_fmt
+    procedure, pass(a) :: clean_zeros => psb_c_csr_clean_zeros
     procedure, pass(a) :: csput_a     => psb_c_csr_csput_a
     procedure, pass(a) :: get_diag    => psb_c_csr_get_diag
     procedure, pass(a) :: csgetptn    => psb_c_csr_csgetptn
@@ -259,6 +261,18 @@ module psb_c_csr_mat_mod
     end subroutine psb_c_csr_triu
   end interface
   
+  !
+  !> 
+  !! \memberof  psb_c_csr_sparse_mat
+  !! \see psb_c_base_mat_mod::psb_c_base_clean_zeros
+  !
+  interface
+    subroutine  psb_c_csr_clean_zeros(a, info)
+      import 
+      class(psb_c_csr_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_c_csr_clean_zeros
+  end interface
   
   !> \memberof psb_c_csr_sparse_mat
   !! \see psb_c_base_mat_mod::psb_c_base_cp_to_coo
@@ -599,6 +613,7 @@ module psb_c_csr_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_lc_mv_csr_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_lc_mv_csr_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_lc_mv_csr_from_fmt
+    procedure, pass(a) :: clean_zeros => psb_lc_csr_clean_zeros
     procedure, pass(a) :: csput_a     => psb_lc_csr_csput_a
     procedure, pass(a) :: get_diag    => psb_lc_csr_get_diag
     procedure, pass(a) :: csgetptn    => psb_lc_csr_csgetptn
@@ -775,7 +790,21 @@ module psb_c_csr_mat_mod
       class(psb_lc_coo_sparse_mat), optional, intent(out) :: l
     end subroutine psb_lc_csr_triu
   end interface
+
+    !
+  !> 
+  !! \memberof  psb_lc_csr_sparse_mat
+  !! \see psb_lc_base_mat_mod::psb_lc_base_clean_zeros
+  !
+  interface
+    subroutine  psb_lc_csr_clean_zeros(a, info)
+      import 
+      class(psb_lc_csr_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_lc_csr_clean_zeros
+  end interface
   
+
   
   !> \memberof psb_lc_csr_sparse_mat
   !! \see psb_lc_base_mat_mod::psb_lc_base_cp_to_coo
diff --git a/base/modules/serial/psb_d_csc_mat_mod.f90 b/base/modules/serial/psb_d_csc_mat_mod.f90
index 8d67e09a..9ab0c2fc 100644
--- a/base/modules/serial/psb_d_csc_mat_mod.f90
+++ b/base/modules/serial/psb_d_csc_mat_mod.f90
@@ -87,6 +87,7 @@ module psb_d_csc_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_d_mv_csc_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_d_mv_csc_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_d_mv_csc_from_fmt
+    procedure, pass(a) :: clean_zeros => psb_d_csc_clean_zeros
     procedure, pass(a) :: csput_a      => psb_d_csc_csput_a
     procedure, pass(a) :: get_diag    => psb_d_csc_get_diag
     procedure, pass(a) :: csgetptn    => psb_d_csc_csgetptn
@@ -142,10 +143,11 @@ module psb_d_csc_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_ld_mv_csc_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_ld_mv_csc_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_ld_mv_csc_from_fmt
-    procedure, pass(a) :: csput_a      => psb_ld_csc_csput_a
+    procedure, pass(a) :: clean_zeros => psb_ld_csc_clean_zeros
+    procedure, pass(a) :: csput_a     => psb_ld_csc_csput_a
     procedure, pass(a) :: get_diag    => psb_ld_csc_get_diag
     procedure, pass(a) :: csgetptn    => psb_ld_csc_csgetptn
-    procedure, pass(a) :: csgetrow   => psb_ld_csc_csgetrow
+    procedure, pass(a) :: csgetrow    => psb_ld_csc_csgetrow
     procedure, pass(a) :: get_nz_col  => ld_csc_get_nz_col
     procedure, pass(a) :: reinit      => psb_ld_csc_reinit
     procedure, pass(a) :: trim        => psb_ld_csc_trim
@@ -311,6 +313,20 @@ module psb_d_csc_mat_mod
     end subroutine psb_d_mv_csc_from_fmt
   end interface
   
+  !
+  !> 
+  !! \memberof  psb_d_csc_sparse_mat
+  !! \see psb_d_base_mat_mod::psb_d_base_clean_zeros
+  !
+  interface
+    subroutine  psb_d_csc_clean_zeros(a, info)
+      import 
+      class(psb_d_csc_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_d_csc_clean_zeros
+  end interface
+  
+  
   !> \memberof psb_d_csc_sparse_mat
   !! \see psb_d_base_mat_mod::psb_d_base_cp_from
   interface 
@@ -702,6 +718,19 @@ module psb_d_csc_mat_mod
     end subroutine psb_ld_mv_csc_from_fmt
   end interface
   
+  !
+  !> 
+  !! \memberof  psb_ld_csc_sparse_mat
+  !! \see psb_ld_base_mat_mod::psb_ld_base_clean_zeros
+  !
+  interface
+    subroutine  psb_ld_csc_clean_zeros(a, info)
+      import 
+      class(psb_ld_csc_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_ld_csc_clean_zeros
+  end interface
+  
   !> \memberof psb_ld_csc_sparse_mat
   !! \see psb_ld_base_mat_mod::psb_ld_base_cp_from
   interface 
diff --git a/base/modules/serial/psb_d_csr_mat_mod.f90 b/base/modules/serial/psb_d_csr_mat_mod.f90
index ce4b3e7c..c84ee4f2 100644
--- a/base/modules/serial/psb_d_csr_mat_mod.f90
+++ b/base/modules/serial/psb_d_csr_mat_mod.f90
@@ -1,3 +1,4 @@
+
 !   
 !                Parallel Sparse BLAS  version 3.5
 !      (C) Copyright 2006-2018
@@ -90,6 +91,7 @@ module psb_d_csr_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_d_mv_csr_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_d_mv_csr_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_d_mv_csr_from_fmt
+    procedure, pass(a) :: clean_zeros => psb_d_csr_clean_zeros
     procedure, pass(a) :: csput_a     => psb_d_csr_csput_a
     procedure, pass(a) :: get_diag    => psb_d_csr_get_diag
     procedure, pass(a) :: csgetptn    => psb_d_csr_csgetptn
@@ -259,6 +261,18 @@ module psb_d_csr_mat_mod
     end subroutine psb_d_csr_triu
   end interface
   
+  !
+  !> 
+  !! \memberof  psb_d_csr_sparse_mat
+  !! \see psb_d_base_mat_mod::psb_d_base_clean_zeros
+  !
+  interface
+    subroutine  psb_d_csr_clean_zeros(a, info)
+      import 
+      class(psb_d_csr_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_d_csr_clean_zeros
+  end interface
   
   !> \memberof psb_d_csr_sparse_mat
   !! \see psb_d_base_mat_mod::psb_d_base_cp_to_coo
@@ -599,6 +613,7 @@ module psb_d_csr_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_ld_mv_csr_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_ld_mv_csr_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_ld_mv_csr_from_fmt
+    procedure, pass(a) :: clean_zeros => psb_ld_csr_clean_zeros
     procedure, pass(a) :: csput_a     => psb_ld_csr_csput_a
     procedure, pass(a) :: get_diag    => psb_ld_csr_get_diag
     procedure, pass(a) :: csgetptn    => psb_ld_csr_csgetptn
@@ -775,7 +790,21 @@ module psb_d_csr_mat_mod
       class(psb_ld_coo_sparse_mat), optional, intent(out) :: l
     end subroutine psb_ld_csr_triu
   end interface
+
+    !
+  !> 
+  !! \memberof  psb_ld_csr_sparse_mat
+  !! \see psb_ld_base_mat_mod::psb_ld_base_clean_zeros
+  !
+  interface
+    subroutine  psb_ld_csr_clean_zeros(a, info)
+      import 
+      class(psb_ld_csr_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_ld_csr_clean_zeros
+  end interface
   
+
   
   !> \memberof psb_ld_csr_sparse_mat
   !! \see psb_ld_base_mat_mod::psb_ld_base_cp_to_coo
diff --git a/base/modules/serial/psb_s_csc_mat_mod.f90 b/base/modules/serial/psb_s_csc_mat_mod.f90
index 188950d2..54278539 100644
--- a/base/modules/serial/psb_s_csc_mat_mod.f90
+++ b/base/modules/serial/psb_s_csc_mat_mod.f90
@@ -87,6 +87,7 @@ module psb_s_csc_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_s_mv_csc_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_s_mv_csc_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_s_mv_csc_from_fmt
+    procedure, pass(a) :: clean_zeros => psb_s_csc_clean_zeros
     procedure, pass(a) :: csput_a      => psb_s_csc_csput_a
     procedure, pass(a) :: get_diag    => psb_s_csc_get_diag
     procedure, pass(a) :: csgetptn    => psb_s_csc_csgetptn
@@ -142,10 +143,11 @@ module psb_s_csc_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_ls_mv_csc_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_ls_mv_csc_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_ls_mv_csc_from_fmt
-    procedure, pass(a) :: csput_a      => psb_ls_csc_csput_a
+    procedure, pass(a) :: clean_zeros => psb_ls_csc_clean_zeros
+    procedure, pass(a) :: csput_a     => psb_ls_csc_csput_a
     procedure, pass(a) :: get_diag    => psb_ls_csc_get_diag
     procedure, pass(a) :: csgetptn    => psb_ls_csc_csgetptn
-    procedure, pass(a) :: csgetrow   => psb_ls_csc_csgetrow
+    procedure, pass(a) :: csgetrow    => psb_ls_csc_csgetrow
     procedure, pass(a) :: get_nz_col  => ls_csc_get_nz_col
     procedure, pass(a) :: reinit      => psb_ls_csc_reinit
     procedure, pass(a) :: trim        => psb_ls_csc_trim
@@ -311,6 +313,20 @@ module psb_s_csc_mat_mod
     end subroutine psb_s_mv_csc_from_fmt
   end interface
   
+  !
+  !> 
+  !! \memberof  psb_s_csc_sparse_mat
+  !! \see psb_s_base_mat_mod::psb_s_base_clean_zeros
+  !
+  interface
+    subroutine  psb_s_csc_clean_zeros(a, info)
+      import 
+      class(psb_s_csc_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_s_csc_clean_zeros
+  end interface
+  
+  
   !> \memberof psb_s_csc_sparse_mat
   !! \see psb_s_base_mat_mod::psb_s_base_cp_from
   interface 
@@ -702,6 +718,19 @@ module psb_s_csc_mat_mod
     end subroutine psb_ls_mv_csc_from_fmt
   end interface
   
+  !
+  !> 
+  !! \memberof  psb_ls_csc_sparse_mat
+  !! \see psb_ls_base_mat_mod::psb_ls_base_clean_zeros
+  !
+  interface
+    subroutine  psb_ls_csc_clean_zeros(a, info)
+      import 
+      class(psb_ls_csc_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_ls_csc_clean_zeros
+  end interface
+  
   !> \memberof psb_ls_csc_sparse_mat
   !! \see psb_ls_base_mat_mod::psb_ls_base_cp_from
   interface 
diff --git a/base/modules/serial/psb_s_csr_mat_mod.f90 b/base/modules/serial/psb_s_csr_mat_mod.f90
index e21a8476..14b41bff 100644
--- a/base/modules/serial/psb_s_csr_mat_mod.f90
+++ b/base/modules/serial/psb_s_csr_mat_mod.f90
@@ -1,3 +1,4 @@
+
 !   
 !                Parallel Sparse BLAS  version 3.5
 !      (C) Copyright 2006-2018
@@ -90,6 +91,7 @@ module psb_s_csr_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_s_mv_csr_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_s_mv_csr_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_s_mv_csr_from_fmt
+    procedure, pass(a) :: clean_zeros => psb_s_csr_clean_zeros
     procedure, pass(a) :: csput_a     => psb_s_csr_csput_a
     procedure, pass(a) :: get_diag    => psb_s_csr_get_diag
     procedure, pass(a) :: csgetptn    => psb_s_csr_csgetptn
@@ -259,6 +261,18 @@ module psb_s_csr_mat_mod
     end subroutine psb_s_csr_triu
   end interface
   
+  !
+  !> 
+  !! \memberof  psb_s_csr_sparse_mat
+  !! \see psb_s_base_mat_mod::psb_s_base_clean_zeros
+  !
+  interface
+    subroutine  psb_s_csr_clean_zeros(a, info)
+      import 
+      class(psb_s_csr_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_s_csr_clean_zeros
+  end interface
   
   !> \memberof psb_s_csr_sparse_mat
   !! \see psb_s_base_mat_mod::psb_s_base_cp_to_coo
@@ -599,6 +613,7 @@ module psb_s_csr_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_ls_mv_csr_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_ls_mv_csr_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_ls_mv_csr_from_fmt
+    procedure, pass(a) :: clean_zeros => psb_ls_csr_clean_zeros
     procedure, pass(a) :: csput_a     => psb_ls_csr_csput_a
     procedure, pass(a) :: get_diag    => psb_ls_csr_get_diag
     procedure, pass(a) :: csgetptn    => psb_ls_csr_csgetptn
@@ -775,7 +790,21 @@ module psb_s_csr_mat_mod
       class(psb_ls_coo_sparse_mat), optional, intent(out) :: l
     end subroutine psb_ls_csr_triu
   end interface
+
+    !
+  !> 
+  !! \memberof  psb_ls_csr_sparse_mat
+  !! \see psb_ls_base_mat_mod::psb_ls_base_clean_zeros
+  !
+  interface
+    subroutine  psb_ls_csr_clean_zeros(a, info)
+      import 
+      class(psb_ls_csr_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_ls_csr_clean_zeros
+  end interface
   
+
   
   !> \memberof psb_ls_csr_sparse_mat
   !! \see psb_ls_base_mat_mod::psb_ls_base_cp_to_coo
diff --git a/base/modules/serial/psb_z_csc_mat_mod.f90 b/base/modules/serial/psb_z_csc_mat_mod.f90
index 1f378036..c6586089 100644
--- a/base/modules/serial/psb_z_csc_mat_mod.f90
+++ b/base/modules/serial/psb_z_csc_mat_mod.f90
@@ -87,6 +87,7 @@ module psb_z_csc_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_z_mv_csc_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_z_mv_csc_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_z_mv_csc_from_fmt
+    procedure, pass(a) :: clean_zeros => psb_z_csc_clean_zeros
     procedure, pass(a) :: csput_a      => psb_z_csc_csput_a
     procedure, pass(a) :: get_diag    => psb_z_csc_get_diag
     procedure, pass(a) :: csgetptn    => psb_z_csc_csgetptn
@@ -142,10 +143,11 @@ module psb_z_csc_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_lz_mv_csc_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_lz_mv_csc_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_lz_mv_csc_from_fmt
-    procedure, pass(a) :: csput_a      => psb_lz_csc_csput_a
+    procedure, pass(a) :: clean_zeros => psb_lz_csc_clean_zeros
+    procedure, pass(a) :: csput_a     => psb_lz_csc_csput_a
     procedure, pass(a) :: get_diag    => psb_lz_csc_get_diag
     procedure, pass(a) :: csgetptn    => psb_lz_csc_csgetptn
-    procedure, pass(a) :: csgetrow   => psb_lz_csc_csgetrow
+    procedure, pass(a) :: csgetrow    => psb_lz_csc_csgetrow
     procedure, pass(a) :: get_nz_col  => lz_csc_get_nz_col
     procedure, pass(a) :: reinit      => psb_lz_csc_reinit
     procedure, pass(a) :: trim        => psb_lz_csc_trim
@@ -311,6 +313,20 @@ module psb_z_csc_mat_mod
     end subroutine psb_z_mv_csc_from_fmt
   end interface
   
+  !
+  !> 
+  !! \memberof  psb_z_csc_sparse_mat
+  !! \see psb_z_base_mat_mod::psb_z_base_clean_zeros
+  !
+  interface
+    subroutine  psb_z_csc_clean_zeros(a, info)
+      import 
+      class(psb_z_csc_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_z_csc_clean_zeros
+  end interface
+  
+  
   !> \memberof psb_z_csc_sparse_mat
   !! \see psb_z_base_mat_mod::psb_z_base_cp_from
   interface 
@@ -702,6 +718,19 @@ module psb_z_csc_mat_mod
     end subroutine psb_lz_mv_csc_from_fmt
   end interface
   
+  !
+  !> 
+  !! \memberof  psb_lz_csc_sparse_mat
+  !! \see psb_lz_base_mat_mod::psb_lz_base_clean_zeros
+  !
+  interface
+    subroutine  psb_lz_csc_clean_zeros(a, info)
+      import 
+      class(psb_lz_csc_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_lz_csc_clean_zeros
+  end interface
+  
   !> \memberof psb_lz_csc_sparse_mat
   !! \see psb_lz_base_mat_mod::psb_lz_base_cp_from
   interface 
diff --git a/base/modules/serial/psb_z_csr_mat_mod.f90 b/base/modules/serial/psb_z_csr_mat_mod.f90
index 9a9cdd26..6e62fa9c 100644
--- a/base/modules/serial/psb_z_csr_mat_mod.f90
+++ b/base/modules/serial/psb_z_csr_mat_mod.f90
@@ -1,3 +1,4 @@
+
 !   
 !                Parallel Sparse BLAS  version 3.5
 !      (C) Copyright 2006-2018
@@ -90,6 +91,7 @@ module psb_z_csr_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_z_mv_csr_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_z_mv_csr_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_z_mv_csr_from_fmt
+    procedure, pass(a) :: clean_zeros => psb_z_csr_clean_zeros
     procedure, pass(a) :: csput_a     => psb_z_csr_csput_a
     procedure, pass(a) :: get_diag    => psb_z_csr_get_diag
     procedure, pass(a) :: csgetptn    => psb_z_csr_csgetptn
@@ -259,6 +261,18 @@ module psb_z_csr_mat_mod
     end subroutine psb_z_csr_triu
   end interface
   
+  !
+  !> 
+  !! \memberof  psb_z_csr_sparse_mat
+  !! \see psb_z_base_mat_mod::psb_z_base_clean_zeros
+  !
+  interface
+    subroutine  psb_z_csr_clean_zeros(a, info)
+      import 
+      class(psb_z_csr_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_z_csr_clean_zeros
+  end interface
   
   !> \memberof psb_z_csr_sparse_mat
   !! \see psb_z_base_mat_mod::psb_z_base_cp_to_coo
@@ -599,6 +613,7 @@ module psb_z_csr_mat_mod
     procedure, pass(a) :: mv_from_coo => psb_lz_mv_csr_from_coo
     procedure, pass(a) :: mv_to_fmt   => psb_lz_mv_csr_to_fmt
     procedure, pass(a) :: mv_from_fmt => psb_lz_mv_csr_from_fmt
+    procedure, pass(a) :: clean_zeros => psb_lz_csr_clean_zeros
     procedure, pass(a) :: csput_a     => psb_lz_csr_csput_a
     procedure, pass(a) :: get_diag    => psb_lz_csr_get_diag
     procedure, pass(a) :: csgetptn    => psb_lz_csr_csgetptn
@@ -775,7 +790,21 @@ module psb_z_csr_mat_mod
       class(psb_lz_coo_sparse_mat), optional, intent(out) :: l
     end subroutine psb_lz_csr_triu
   end interface
+
+    !
+  !> 
+  !! \memberof  psb_lz_csr_sparse_mat
+  !! \see psb_lz_base_mat_mod::psb_lz_base_clean_zeros
+  !
+  interface
+    subroutine  psb_lz_csr_clean_zeros(a, info)
+      import 
+      class(psb_lz_csr_sparse_mat), intent(inout) :: a
+      integer(psb_ipk_), intent(out)              :: info
+    end subroutine psb_lz_csr_clean_zeros
+  end interface
   
+
   
   !> \memberof psb_lz_csr_sparse_mat
   !! \see psb_lz_base_mat_mod::psb_lz_base_cp_to_coo
diff --git a/base/serial/impl/psb_c_csc_impl.f90 b/base/serial/impl/psb_c_csc_impl.f90
index 179c60a0..c513e06b 100644
--- a/base/serial/impl/psb_c_csc_impl.f90
+++ b/base/serial/impl/psb_c_csc_impl.f90
@@ -2366,7 +2366,35 @@ subroutine psb_c_mv_csc_from_fmt(a,b,info)
 
 end subroutine psb_c_mv_csc_from_fmt
 
-
+subroutine  psb_c_csc_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_c_csc_mat_mod, psb_protect_name => psb_c_csc_clean_zeros
+  implicit none 
+  class(psb_c_csc_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_ipk_) :: i, j, k, nc
+  integer(psb_ipk_), allocatable :: ilcp(:) 
+  
+  info = 0
+  call a%sync()
+  nc   = a%get_ncols()
+  ilcp = a%icp(:) 
+  a%icp(1) = 1
+  j        = a%icp(1) 
+  do i=1, nc
+    do k = ilcp(i), ilcp(i+1) -1
+      if (a%val(k) /= czero) then
+        a%val(j) = a%val(k)
+        a%ia(j)  = a%ia(k)
+        j = j + 1
+      end if
+    end do
+    a%icp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_c_csc_clean_zeros
 
 subroutine psb_c_cp_csc_from_fmt(a,b,info) 
   use psb_const_mod
@@ -4233,6 +4261,36 @@ subroutine psb_lc_cp_csc_from_fmt(a,b,info)
   
 end subroutine psb_lc_cp_csc_from_fmt
 
+subroutine  psb_lc_csc_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_c_csc_mat_mod, psb_protect_name => psb_lc_csc_clean_zeros
+  implicit none 
+  class(psb_lc_csc_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_lpk_) :: i, j, k, nc
+  integer(psb_lpk_), allocatable :: ilcp(:) 
+  
+  info = 0
+  call a%sync()
+  nc   = a%get_ncols()
+  ilcp = a%icp(:) 
+  a%icp(1) = 1
+  j        = a%icp(1) 
+  do i=1, nc
+    do k = ilcp(i), ilcp(i+1) -1
+      if (a%val(k) /= czero) then
+        a%val(j) = a%val(k)
+        a%ia(j)  = a%ia(k)
+        j = j + 1
+      end if
+    end do
+    a%icp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_lc_csc_clean_zeros
+
 
 subroutine psb_lc_csc_mold(a,b,info) 
   use psb_c_csc_mat_mod, psb_protect_name => psb_lc_csc_mold
diff --git a/base/serial/impl/psb_c_csr_impl.f90 b/base/serial/impl/psb_c_csr_impl.f90
index 9afc3c59..60742158 100644
--- a/base/serial/impl/psb_c_csr_impl.f90
+++ b/base/serial/impl/psb_c_csr_impl.f90
@@ -3225,6 +3225,36 @@ subroutine psb_c_cp_csr_from_fmt(a,b,info)
   end select
 end subroutine psb_c_cp_csr_from_fmt
 
+subroutine  psb_c_csr_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_c_csr_mat_mod, psb_protect_name => psb_c_csr_clean_zeros
+  implicit none 
+  class(psb_c_csr_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_ipk_) :: i, j, k, nr
+  integer(psb_ipk_), allocatable :: ilrp(:) 
+  
+  info = 0
+  call a%sync()
+  nr   = a%get_nrows()
+  ilrp = a%irp(:) 
+  a%irp(1) = 1
+  j        = a%irp(1) 
+  do i=1, nr
+    do k = ilrp(i), ilrp(i+1) -1
+      if (a%val(k) /= czero) then
+        a%val(j) = a%val(k)
+        a%ja(j)  = a%ja(k)
+        j = j + 1
+      end if
+    end do
+    a%irp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_c_csr_clean_zeros
+
 subroutine psb_ccsrspspmm(a,b,c,info)
   use psb_c_mat_mod
   use psb_serial_mod, psb_protect_name => psb_ccsrspspmm
@@ -5323,6 +5353,37 @@ subroutine psb_lc_cp_csr_from_fmt(a,b,info)
   end select
 end subroutine psb_lc_cp_csr_from_fmt
 
+
+subroutine  psb_lc_csr_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_c_csr_mat_mod, psb_protect_name => psb_lc_csr_clean_zeros
+  implicit none 
+  class(psb_lc_csr_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_lpk_) :: i, j, k, nr
+  integer(psb_lpk_), allocatable :: ilrp(:) 
+  
+  info = 0 
+  call a%sync()
+  nr   = a%get_nrows()
+  ilrp = a%irp(:) 
+  a%irp(1) = 1
+  j        = a%irp(1) 
+  do i=1, nr
+    do k = ilrp(i), ilrp(i+1) -1
+      if (a%val(k) /= czero) then
+        a%val(j) = a%val(k)
+        a%ja(j)  = a%ja(k)
+        j = j + 1
+      end if
+    end do
+    a%irp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_lc_csr_clean_zeros
+
 subroutine psb_lccsrspspmm(a,b,c,info)
   use psb_c_mat_mod
   use psb_serial_mod, psb_protect_name => psb_lccsrspspmm
diff --git a/base/serial/impl/psb_d_csc_impl.f90 b/base/serial/impl/psb_d_csc_impl.f90
index 8883d586..bb889f5d 100644
--- a/base/serial/impl/psb_d_csc_impl.f90
+++ b/base/serial/impl/psb_d_csc_impl.f90
@@ -2366,7 +2366,35 @@ subroutine psb_d_mv_csc_from_fmt(a,b,info)
 
 end subroutine psb_d_mv_csc_from_fmt
 
-
+subroutine  psb_d_csc_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_d_csc_mat_mod, psb_protect_name => psb_d_csc_clean_zeros
+  implicit none 
+  class(psb_d_csc_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_ipk_) :: i, j, k, nc
+  integer(psb_ipk_), allocatable :: ilcp(:) 
+  
+  info = 0
+  call a%sync()
+  nc   = a%get_ncols()
+  ilcp = a%icp(:) 
+  a%icp(1) = 1
+  j        = a%icp(1) 
+  do i=1, nc
+    do k = ilcp(i), ilcp(i+1) -1
+      if (a%val(k) /= dzero) then
+        a%val(j) = a%val(k)
+        a%ia(j)  = a%ia(k)
+        j = j + 1
+      end if
+    end do
+    a%icp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_d_csc_clean_zeros
 
 subroutine psb_d_cp_csc_from_fmt(a,b,info) 
   use psb_const_mod
@@ -4233,6 +4261,36 @@ subroutine psb_ld_cp_csc_from_fmt(a,b,info)
   
 end subroutine psb_ld_cp_csc_from_fmt
 
+subroutine  psb_ld_csc_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_d_csc_mat_mod, psb_protect_name => psb_ld_csc_clean_zeros
+  implicit none 
+  class(psb_ld_csc_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_lpk_) :: i, j, k, nc
+  integer(psb_lpk_), allocatable :: ilcp(:) 
+  
+  info = 0
+  call a%sync()
+  nc   = a%get_ncols()
+  ilcp = a%icp(:) 
+  a%icp(1) = 1
+  j        = a%icp(1) 
+  do i=1, nc
+    do k = ilcp(i), ilcp(i+1) -1
+      if (a%val(k) /= dzero) then
+        a%val(j) = a%val(k)
+        a%ia(j)  = a%ia(k)
+        j = j + 1
+      end if
+    end do
+    a%icp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_ld_csc_clean_zeros
+
 
 subroutine psb_ld_csc_mold(a,b,info) 
   use psb_d_csc_mat_mod, psb_protect_name => psb_ld_csc_mold
diff --git a/base/serial/impl/psb_d_csr_impl.f90 b/base/serial/impl/psb_d_csr_impl.f90
index 5ddec8b2..97cc78b6 100644
--- a/base/serial/impl/psb_d_csr_impl.f90
+++ b/base/serial/impl/psb_d_csr_impl.f90
@@ -3225,6 +3225,36 @@ subroutine psb_d_cp_csr_from_fmt(a,b,info)
   end select
 end subroutine psb_d_cp_csr_from_fmt
 
+subroutine  psb_d_csr_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_d_csr_mat_mod, psb_protect_name => psb_d_csr_clean_zeros
+  implicit none 
+  class(psb_d_csr_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_ipk_) :: i, j, k, nr
+  integer(psb_ipk_), allocatable :: ilrp(:) 
+  
+  info = 0
+  call a%sync()
+  nr   = a%get_nrows()
+  ilrp = a%irp(:) 
+  a%irp(1) = 1
+  j        = a%irp(1) 
+  do i=1, nr
+    do k = ilrp(i), ilrp(i+1) -1
+      if (a%val(k) /= dzero) then
+        a%val(j) = a%val(k)
+        a%ja(j)  = a%ja(k)
+        j = j + 1
+      end if
+    end do
+    a%irp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_d_csr_clean_zeros
+
 subroutine psb_dcsrspspmm(a,b,c,info)
   use psb_d_mat_mod
   use psb_serial_mod, psb_protect_name => psb_dcsrspspmm
@@ -5323,6 +5353,37 @@ subroutine psb_ld_cp_csr_from_fmt(a,b,info)
   end select
 end subroutine psb_ld_cp_csr_from_fmt
 
+
+subroutine  psb_ld_csr_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_d_csr_mat_mod, psb_protect_name => psb_ld_csr_clean_zeros
+  implicit none 
+  class(psb_ld_csr_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_lpk_) :: i, j, k, nr
+  integer(psb_lpk_), allocatable :: ilrp(:) 
+  
+  info = 0 
+  call a%sync()
+  nr   = a%get_nrows()
+  ilrp = a%irp(:) 
+  a%irp(1) = 1
+  j        = a%irp(1) 
+  do i=1, nr
+    do k = ilrp(i), ilrp(i+1) -1
+      if (a%val(k) /= dzero) then
+        a%val(j) = a%val(k)
+        a%ja(j)  = a%ja(k)
+        j = j + 1
+      end if
+    end do
+    a%irp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_ld_csr_clean_zeros
+
 subroutine psb_ldcsrspspmm(a,b,c,info)
   use psb_d_mat_mod
   use psb_serial_mod, psb_protect_name => psb_ldcsrspspmm
diff --git a/base/serial/impl/psb_s_csc_impl.f90 b/base/serial/impl/psb_s_csc_impl.f90
index ecfa986d..98736c2b 100644
--- a/base/serial/impl/psb_s_csc_impl.f90
+++ b/base/serial/impl/psb_s_csc_impl.f90
@@ -2366,7 +2366,35 @@ subroutine psb_s_mv_csc_from_fmt(a,b,info)
 
 end subroutine psb_s_mv_csc_from_fmt
 
-
+subroutine  psb_s_csc_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_s_csc_mat_mod, psb_protect_name => psb_s_csc_clean_zeros
+  implicit none 
+  class(psb_s_csc_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_ipk_) :: i, j, k, nc
+  integer(psb_ipk_), allocatable :: ilcp(:) 
+  
+  info = 0
+  call a%sync()
+  nc   = a%get_ncols()
+  ilcp = a%icp(:) 
+  a%icp(1) = 1
+  j        = a%icp(1) 
+  do i=1, nc
+    do k = ilcp(i), ilcp(i+1) -1
+      if (a%val(k) /= szero) then
+        a%val(j) = a%val(k)
+        a%ia(j)  = a%ia(k)
+        j = j + 1
+      end if
+    end do
+    a%icp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_s_csc_clean_zeros
 
 subroutine psb_s_cp_csc_from_fmt(a,b,info) 
   use psb_const_mod
@@ -4233,6 +4261,36 @@ subroutine psb_ls_cp_csc_from_fmt(a,b,info)
   
 end subroutine psb_ls_cp_csc_from_fmt
 
+subroutine  psb_ls_csc_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_s_csc_mat_mod, psb_protect_name => psb_ls_csc_clean_zeros
+  implicit none 
+  class(psb_ls_csc_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_lpk_) :: i, j, k, nc
+  integer(psb_lpk_), allocatable :: ilcp(:) 
+  
+  info = 0
+  call a%sync()
+  nc   = a%get_ncols()
+  ilcp = a%icp(:) 
+  a%icp(1) = 1
+  j        = a%icp(1) 
+  do i=1, nc
+    do k = ilcp(i), ilcp(i+1) -1
+      if (a%val(k) /= szero) then
+        a%val(j) = a%val(k)
+        a%ia(j)  = a%ia(k)
+        j = j + 1
+      end if
+    end do
+    a%icp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_ls_csc_clean_zeros
+
 
 subroutine psb_ls_csc_mold(a,b,info) 
   use psb_s_csc_mat_mod, psb_protect_name => psb_ls_csc_mold
diff --git a/base/serial/impl/psb_s_csr_impl.f90 b/base/serial/impl/psb_s_csr_impl.f90
index a01336ed..7e4a64a2 100644
--- a/base/serial/impl/psb_s_csr_impl.f90
+++ b/base/serial/impl/psb_s_csr_impl.f90
@@ -3225,6 +3225,36 @@ subroutine psb_s_cp_csr_from_fmt(a,b,info)
   end select
 end subroutine psb_s_cp_csr_from_fmt
 
+subroutine  psb_s_csr_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_s_csr_mat_mod, psb_protect_name => psb_s_csr_clean_zeros
+  implicit none 
+  class(psb_s_csr_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_ipk_) :: i, j, k, nr
+  integer(psb_ipk_), allocatable :: ilrp(:) 
+  
+  info = 0
+  call a%sync()
+  nr   = a%get_nrows()
+  ilrp = a%irp(:) 
+  a%irp(1) = 1
+  j        = a%irp(1) 
+  do i=1, nr
+    do k = ilrp(i), ilrp(i+1) -1
+      if (a%val(k) /= szero) then
+        a%val(j) = a%val(k)
+        a%ja(j)  = a%ja(k)
+        j = j + 1
+      end if
+    end do
+    a%irp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_s_csr_clean_zeros
+
 subroutine psb_scsrspspmm(a,b,c,info)
   use psb_s_mat_mod
   use psb_serial_mod, psb_protect_name => psb_scsrspspmm
@@ -5323,6 +5353,37 @@ subroutine psb_ls_cp_csr_from_fmt(a,b,info)
   end select
 end subroutine psb_ls_cp_csr_from_fmt
 
+
+subroutine  psb_ls_csr_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_s_csr_mat_mod, psb_protect_name => psb_ls_csr_clean_zeros
+  implicit none 
+  class(psb_ls_csr_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_lpk_) :: i, j, k, nr
+  integer(psb_lpk_), allocatable :: ilrp(:) 
+  
+  info = 0 
+  call a%sync()
+  nr   = a%get_nrows()
+  ilrp = a%irp(:) 
+  a%irp(1) = 1
+  j        = a%irp(1) 
+  do i=1, nr
+    do k = ilrp(i), ilrp(i+1) -1
+      if (a%val(k) /= szero) then
+        a%val(j) = a%val(k)
+        a%ja(j)  = a%ja(k)
+        j = j + 1
+      end if
+    end do
+    a%irp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_ls_csr_clean_zeros
+
 subroutine psb_lscsrspspmm(a,b,c,info)
   use psb_s_mat_mod
   use psb_serial_mod, psb_protect_name => psb_lscsrspspmm
diff --git a/base/serial/impl/psb_z_csc_impl.f90 b/base/serial/impl/psb_z_csc_impl.f90
index f3e604c1..c7c819a8 100644
--- a/base/serial/impl/psb_z_csc_impl.f90
+++ b/base/serial/impl/psb_z_csc_impl.f90
@@ -2366,7 +2366,35 @@ subroutine psb_z_mv_csc_from_fmt(a,b,info)
 
 end subroutine psb_z_mv_csc_from_fmt
 
-
+subroutine  psb_z_csc_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_z_csc_mat_mod, psb_protect_name => psb_z_csc_clean_zeros
+  implicit none 
+  class(psb_z_csc_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_ipk_) :: i, j, k, nc
+  integer(psb_ipk_), allocatable :: ilcp(:) 
+  
+  info = 0
+  call a%sync()
+  nc   = a%get_ncols()
+  ilcp = a%icp(:) 
+  a%icp(1) = 1
+  j        = a%icp(1) 
+  do i=1, nc
+    do k = ilcp(i), ilcp(i+1) -1
+      if (a%val(k) /= zzero) then
+        a%val(j) = a%val(k)
+        a%ia(j)  = a%ia(k)
+        j = j + 1
+      end if
+    end do
+    a%icp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_z_csc_clean_zeros
 
 subroutine psb_z_cp_csc_from_fmt(a,b,info) 
   use psb_const_mod
@@ -4233,6 +4261,36 @@ subroutine psb_lz_cp_csc_from_fmt(a,b,info)
   
 end subroutine psb_lz_cp_csc_from_fmt
 
+subroutine  psb_lz_csc_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_z_csc_mat_mod, psb_protect_name => psb_lz_csc_clean_zeros
+  implicit none 
+  class(psb_lz_csc_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_lpk_) :: i, j, k, nc
+  integer(psb_lpk_), allocatable :: ilcp(:) 
+  
+  info = 0
+  call a%sync()
+  nc   = a%get_ncols()
+  ilcp = a%icp(:) 
+  a%icp(1) = 1
+  j        = a%icp(1) 
+  do i=1, nc
+    do k = ilcp(i), ilcp(i+1) -1
+      if (a%val(k) /= zzero) then
+        a%val(j) = a%val(k)
+        a%ia(j)  = a%ia(k)
+        j = j + 1
+      end if
+    end do
+    a%icp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_lz_csc_clean_zeros
+
 
 subroutine psb_lz_csc_mold(a,b,info) 
   use psb_z_csc_mat_mod, psb_protect_name => psb_lz_csc_mold
diff --git a/base/serial/impl/psb_z_csr_impl.f90 b/base/serial/impl/psb_z_csr_impl.f90
index 0cf34879..038a1f47 100644
--- a/base/serial/impl/psb_z_csr_impl.f90
+++ b/base/serial/impl/psb_z_csr_impl.f90
@@ -3225,6 +3225,36 @@ subroutine psb_z_cp_csr_from_fmt(a,b,info)
   end select
 end subroutine psb_z_cp_csr_from_fmt
 
+subroutine  psb_z_csr_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_z_csr_mat_mod, psb_protect_name => psb_z_csr_clean_zeros
+  implicit none 
+  class(psb_z_csr_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_ipk_) :: i, j, k, nr
+  integer(psb_ipk_), allocatable :: ilrp(:) 
+  
+  info = 0
+  call a%sync()
+  nr   = a%get_nrows()
+  ilrp = a%irp(:) 
+  a%irp(1) = 1
+  j        = a%irp(1) 
+  do i=1, nr
+    do k = ilrp(i), ilrp(i+1) -1
+      if (a%val(k) /= zzero) then
+        a%val(j) = a%val(k)
+        a%ja(j)  = a%ja(k)
+        j = j + 1
+      end if
+    end do
+    a%irp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_z_csr_clean_zeros
+
 subroutine psb_zcsrspspmm(a,b,c,info)
   use psb_z_mat_mod
   use psb_serial_mod, psb_protect_name => psb_zcsrspspmm
@@ -5323,6 +5353,37 @@ subroutine psb_lz_cp_csr_from_fmt(a,b,info)
   end select
 end subroutine psb_lz_cp_csr_from_fmt
 
+
+subroutine  psb_lz_csr_clean_zeros(a, info)
+  use psb_error_mod
+  use psb_z_csr_mat_mod, psb_protect_name => psb_lz_csr_clean_zeros
+  implicit none 
+  class(psb_lz_csr_sparse_mat), intent(inout) :: a
+  integer(psb_ipk_) :: info
+  !
+  integer(psb_lpk_) :: i, j, k, nr
+  integer(psb_lpk_), allocatable :: ilrp(:) 
+  
+  info = 0 
+  call a%sync()
+  nr   = a%get_nrows()
+  ilrp = a%irp(:) 
+  a%irp(1) = 1
+  j        = a%irp(1) 
+  do i=1, nr
+    do k = ilrp(i), ilrp(i+1) -1
+      if (a%val(k) /= zzero) then
+        a%val(j) = a%val(k)
+        a%ja(j)  = a%ja(k)
+        j = j + 1
+      end if
+    end do
+    a%irp(i+1) = j
+  end do
+  call a%trim()
+  call a%set_host()
+end subroutine psb_lz_csr_clean_zeros
+
 subroutine psb_lzcsrspspmm(a,b,c,info)
   use psb_z_mat_mod
   use psb_serial_mod, psb_protect_name => psb_lzcsrspspmm