diff --git a/Changelog b/Changelog
index d80ad994..2dcb965b 100644
--- a/Changelog
+++ b/Changelog
@@ -1,5 +1,6 @@
 Changelog. A lot less detailed than usual, at least for past
 history.
+2013/04/20: Fix add-by-one for unit triangular matrices.
 	
 2013/03/31: Implement CLONE method for vectors, maps and preconditioners.
 	    Make base_prec abstract.      
diff --git a/base/serial/impl/psb_c_coo_impl.f90 b/base/serial/impl/psb_c_coo_impl.f90
index d675785b..b86184b0 100644
--- a/base/serial/impl/psb_c_coo_impl.f90
+++ b/base/serial/impl/psb_c_coo_impl.f90
@@ -1788,6 +1788,12 @@ subroutine psb_c_coo_rowsum(d,a)
     d(i) = d(i) + a%val(j)
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + cone
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
@@ -1836,6 +1842,12 @@ subroutine psb_c_coo_arwsum(d,a)
     d(i) = d(i) + abs(a%val(j))
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + sone
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
@@ -1883,6 +1895,12 @@ subroutine psb_c_coo_colsum(d,a)
     k    = a%ja(j)
     d(k) = d(k) + a%val(j)
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + cone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1931,6 +1949,12 @@ subroutine psb_c_coo_aclsum(d,a)
     k    = a%ja(j)
     d(k) = d(k) + abs(a%val(j))
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + sone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
diff --git a/base/serial/impl/psb_c_csc_impl.f90 b/base/serial/impl/psb_c_csc_impl.f90
index dd9dbf96..6799fdf2 100644
--- a/base/serial/impl/psb_c_csc_impl.f90
+++ b/base/serial/impl/psb_c_csc_impl.f90
@@ -1192,6 +1192,12 @@ subroutine psb_c_csc_colsum(d,a)
       d(i) = d(i) + (a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_ncols()
+      d(i) = d(i) + cone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1241,6 +1247,12 @@ subroutine psb_c_csc_aclsum(d,a)
       d(i) = d(i) + abs(a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_ncols()
+      d(i) = d(i) + sone
+    end do
+  end if
 
   call psb_erractionrestore(err_act)
   return  
@@ -1292,6 +1304,12 @@ subroutine psb_c_csc_rowsum(d,a)
     end do
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_nrows()
+      d(i) = d(i) + cone
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
@@ -1335,7 +1353,6 @@ subroutine psb_c_csc_arwsum(d,a)
   end if
 
   d   = szero
-
   do i=1, m
     do j=a%icp(i),a%icp(i+1)-1
       k = a%ia(j)
@@ -1343,6 +1360,12 @@ subroutine psb_c_csc_arwsum(d,a)
     end do
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_nrows()
+      d(i) = d(i) + sone
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
diff --git a/base/serial/impl/psb_c_csr_impl.f90 b/base/serial/impl/psb_c_csr_impl.f90
index f7edbf54..be6f0441 100644
--- a/base/serial/impl/psb_c_csr_impl.f90
+++ b/base/serial/impl/psb_c_csr_impl.f90
@@ -1397,6 +1397,12 @@ subroutine psb_c_csr_rowsum(d,a)
       d(i) = d(i) + (a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + cone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1446,6 +1452,12 @@ subroutine psb_c_csr_arwsum(d,a)
       d(i) = d(i) + abs(a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + sone
+    end do
+  end if
 
   call psb_erractionrestore(err_act)
   return  
@@ -1496,6 +1508,12 @@ subroutine psb_c_csr_colsum(d,a)
       d(k) = d(k) + (a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + cone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1547,6 +1565,12 @@ subroutine psb_c_csr_aclsum(d,a)
       d(k) = d(k) + abs(a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + sone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
diff --git a/base/serial/impl/psb_d_coo_impl.f90 b/base/serial/impl/psb_d_coo_impl.f90
index ddf322d6..1238ad93 100644
--- a/base/serial/impl/psb_d_coo_impl.f90
+++ b/base/serial/impl/psb_d_coo_impl.f90
@@ -1788,6 +1788,12 @@ subroutine psb_d_coo_rowsum(d,a)
     d(i) = d(i) + a%val(j)
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + done
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
@@ -1836,6 +1842,12 @@ subroutine psb_d_coo_arwsum(d,a)
     d(i) = d(i) + abs(a%val(j))
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + done
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
@@ -1883,6 +1895,12 @@ subroutine psb_d_coo_colsum(d,a)
     k    = a%ja(j)
     d(k) = d(k) + a%val(j)
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + done
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1931,6 +1949,12 @@ subroutine psb_d_coo_aclsum(d,a)
     k    = a%ja(j)
     d(k) = d(k) + abs(a%val(j))
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + done
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
diff --git a/base/serial/impl/psb_d_csc_impl.f90 b/base/serial/impl/psb_d_csc_impl.f90
index b6aedd49..febab98c 100644
--- a/base/serial/impl/psb_d_csc_impl.f90
+++ b/base/serial/impl/psb_d_csc_impl.f90
@@ -1192,6 +1192,12 @@ subroutine psb_d_csc_colsum(d,a)
       d(i) = d(i) + (a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_ncols()
+      d(i) = d(i) + done
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1241,6 +1247,12 @@ subroutine psb_d_csc_aclsum(d,a)
       d(i) = d(i) + abs(a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_ncols()
+      d(i) = d(i) + done
+    end do
+  end if
 
   call psb_erractionrestore(err_act)
   return  
@@ -1292,6 +1304,12 @@ subroutine psb_d_csc_rowsum(d,a)
     end do
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_nrows()
+      d(i) = d(i) + done
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
@@ -1335,7 +1353,6 @@ subroutine psb_d_csc_arwsum(d,a)
   end if
 
   d   = dzero
-
   do i=1, m
     do j=a%icp(i),a%icp(i+1)-1
       k = a%ia(j)
@@ -1343,6 +1360,12 @@ subroutine psb_d_csc_arwsum(d,a)
     end do
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_nrows()
+      d(i) = d(i) + done
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
diff --git a/base/serial/impl/psb_d_csr_impl.f90 b/base/serial/impl/psb_d_csr_impl.f90
index 6d20a8f2..9ad2db78 100644
--- a/base/serial/impl/psb_d_csr_impl.f90
+++ b/base/serial/impl/psb_d_csr_impl.f90
@@ -1397,6 +1397,12 @@ subroutine psb_d_csr_rowsum(d,a)
       d(i) = d(i) + (a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + done
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1446,6 +1452,12 @@ subroutine psb_d_csr_arwsum(d,a)
       d(i) = d(i) + abs(a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + done
+    end do
+  end if
 
   call psb_erractionrestore(err_act)
   return  
@@ -1496,6 +1508,12 @@ subroutine psb_d_csr_colsum(d,a)
       d(k) = d(k) + (a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + done
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1547,6 +1565,12 @@ subroutine psb_d_csr_aclsum(d,a)
       d(k) = d(k) + abs(a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + done
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
diff --git a/base/serial/impl/psb_s_coo_impl.f90 b/base/serial/impl/psb_s_coo_impl.f90
index c26eb9ab..38a8fa76 100644
--- a/base/serial/impl/psb_s_coo_impl.f90
+++ b/base/serial/impl/psb_s_coo_impl.f90
@@ -1788,6 +1788,12 @@ subroutine psb_s_coo_rowsum(d,a)
     d(i) = d(i) + a%val(j)
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + sone
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
@@ -1836,6 +1842,12 @@ subroutine psb_s_coo_arwsum(d,a)
     d(i) = d(i) + abs(a%val(j))
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + sone
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
@@ -1883,6 +1895,12 @@ subroutine psb_s_coo_colsum(d,a)
     k    = a%ja(j)
     d(k) = d(k) + a%val(j)
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + sone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1931,6 +1949,12 @@ subroutine psb_s_coo_aclsum(d,a)
     k    = a%ja(j)
     d(k) = d(k) + abs(a%val(j))
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + sone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
diff --git a/base/serial/impl/psb_s_csc_impl.f90 b/base/serial/impl/psb_s_csc_impl.f90
index 5c9e977e..769670f3 100644
--- a/base/serial/impl/psb_s_csc_impl.f90
+++ b/base/serial/impl/psb_s_csc_impl.f90
@@ -1192,6 +1192,12 @@ subroutine psb_s_csc_colsum(d,a)
       d(i) = d(i) + (a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_ncols()
+      d(i) = d(i) + sone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1241,6 +1247,12 @@ subroutine psb_s_csc_aclsum(d,a)
       d(i) = d(i) + abs(a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_ncols()
+      d(i) = d(i) + sone
+    end do
+  end if
 
   call psb_erractionrestore(err_act)
   return  
@@ -1292,6 +1304,12 @@ subroutine psb_s_csc_rowsum(d,a)
     end do
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_nrows()
+      d(i) = d(i) + sone
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
@@ -1335,7 +1353,6 @@ subroutine psb_s_csc_arwsum(d,a)
   end if
 
   d   = szero
-
   do i=1, m
     do j=a%icp(i),a%icp(i+1)-1
       k = a%ia(j)
@@ -1343,6 +1360,12 @@ subroutine psb_s_csc_arwsum(d,a)
     end do
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_nrows()
+      d(i) = d(i) + sone
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
diff --git a/base/serial/impl/psb_s_csr_impl.f90 b/base/serial/impl/psb_s_csr_impl.f90
index 0088fead..68f0535a 100644
--- a/base/serial/impl/psb_s_csr_impl.f90
+++ b/base/serial/impl/psb_s_csr_impl.f90
@@ -1397,6 +1397,12 @@ subroutine psb_s_csr_rowsum(d,a)
       d(i) = d(i) + (a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + sone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1446,6 +1452,12 @@ subroutine psb_s_csr_arwsum(d,a)
       d(i) = d(i) + abs(a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + sone
+    end do
+  end if
 
   call psb_erractionrestore(err_act)
   return  
@@ -1496,6 +1508,12 @@ subroutine psb_s_csr_colsum(d,a)
       d(k) = d(k) + (a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + sone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1547,6 +1565,12 @@ subroutine psb_s_csr_aclsum(d,a)
       d(k) = d(k) + abs(a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + sone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
diff --git a/base/serial/impl/psb_z_coo_impl.f90 b/base/serial/impl/psb_z_coo_impl.f90
index e43f52dd..7cbc1739 100644
--- a/base/serial/impl/psb_z_coo_impl.f90
+++ b/base/serial/impl/psb_z_coo_impl.f90
@@ -1788,6 +1788,12 @@ subroutine psb_z_coo_rowsum(d,a)
     d(i) = d(i) + a%val(j)
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + zone
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
@@ -1836,6 +1842,12 @@ subroutine psb_z_coo_arwsum(d,a)
     d(i) = d(i) + abs(a%val(j))
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + done
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
@@ -1883,6 +1895,12 @@ subroutine psb_z_coo_colsum(d,a)
     k    = a%ja(j)
     d(k) = d(k) + a%val(j)
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + zone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1931,6 +1949,12 @@ subroutine psb_z_coo_aclsum(d,a)
     k    = a%ja(j)
     d(k) = d(k) + abs(a%val(j))
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + done
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
diff --git a/base/serial/impl/psb_z_csc_impl.f90 b/base/serial/impl/psb_z_csc_impl.f90
index 40a267fe..dff25d0c 100644
--- a/base/serial/impl/psb_z_csc_impl.f90
+++ b/base/serial/impl/psb_z_csc_impl.f90
@@ -1192,6 +1192,12 @@ subroutine psb_z_csc_colsum(d,a)
       d(i) = d(i) + (a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_ncols()
+      d(i) = d(i) + zone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1241,6 +1247,12 @@ subroutine psb_z_csc_aclsum(d,a)
       d(i) = d(i) + abs(a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_ncols()
+      d(i) = d(i) + done
+    end do
+  end if
 
   call psb_erractionrestore(err_act)
   return  
@@ -1292,6 +1304,12 @@ subroutine psb_z_csc_rowsum(d,a)
     end do
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_nrows()
+      d(i) = d(i) + zone
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
@@ -1335,7 +1353,6 @@ subroutine psb_z_csc_arwsum(d,a)
   end if
 
   d   = dzero
-
   do i=1, m
     do j=a%icp(i),a%icp(i+1)-1
       k = a%ia(j)
@@ -1343,6 +1360,12 @@ subroutine psb_z_csc_arwsum(d,a)
     end do
   end do
 
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, a%get_nrows()
+      d(i) = d(i) + done
+    end do
+  end if
+
   return
   call psb_erractionrestore(err_act)
   return  
diff --git a/base/serial/impl/psb_z_csr_impl.f90 b/base/serial/impl/psb_z_csr_impl.f90
index 65d5fcac..2b7cc374 100644
--- a/base/serial/impl/psb_z_csr_impl.f90
+++ b/base/serial/impl/psb_z_csr_impl.f90
@@ -1397,6 +1397,12 @@ subroutine psb_z_csr_rowsum(d,a)
       d(i) = d(i) + (a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + zone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1446,6 +1452,12 @@ subroutine psb_z_csr_arwsum(d,a)
       d(i) = d(i) + abs(a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, m
+      d(i) = d(i) + done
+    end do
+  end if
 
   call psb_erractionrestore(err_act)
   return  
@@ -1496,6 +1508,12 @@ subroutine psb_z_csr_colsum(d,a)
       d(k) = d(k) + (a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + zone
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)
@@ -1547,6 +1565,12 @@ subroutine psb_z_csr_aclsum(d,a)
       d(k) = d(k) + abs(a%val(j))
     end do
   end do
+  
+  if (a%is_triangle().and.a%is_unit()) then 
+    do i=1, n
+      d(i) = d(i) + done
+    end do
+  end if
 
   return
   call psb_erractionrestore(err_act)