start revising BDY segments description in NEMO manual

latex/NEMO/namelists/nambdy_index

+!-----------------------------------------------------------------------
+&nambdy        !  unstructured open boundaries                          (default: OFF)
+!-----------------------------------------------------------------------
+   ln_bdy         = .true.   !  Use unstructured open boundaries
+   nb_bdy         = 2        !  number of open boundary sets
+   ln_coords_file = F F      !  =T : read bdy coordinates from file
+   nn_rimwidth    = 1 1      !  width of the relaxation zone
+/
+
+! BDY segments
+&nambdy_index
+   ctypebdy = 'N'             ! North boundary segment
+   nbdyind = -1               ! Index along the constant dimension, if -1 then set boundary to whole side of model domain.
+   nbdybeg = 2                ! 
+   nbdyend = 200
+/
+&nambdy_index
+   ctypebdy = 'E'             ! East boundary segment
+   nbdyind = -1               ! Automatic boundary definition: if -1 then set boundary to whole side of model domain.  
+/

latex/NEMO/subfiles/chap_LBC.tex

@@ -303,6 +303,12 @@ The 1-d arrays $mig0(1:jpi)$ and $mjg0(1:jpj)$ are used to get original global d
   \label{lst:nambdy}
 \end{listing}
 
+\begin{listing}
+\nlstlocal{nambdy_index}
+  \caption{\forcode{&nambdy & nambdy_index}}
+  \label{lst:nambdy_index}
+\end{listing}
+
 \begin{listing}
   \nlst{nambdy_dta}
   \caption{\forcode{&nambdy_dta}}
@@ -328,11 +334,11 @@ The BDY module is activated by setting \np[=.true.]{ln_bdy}{ln\_bdy} .
 It is possible to define more than one boundary ``set'' and apply different boundary conditions to each set.
 The number of boundary sets is defined by \np{nb_bdy}{nb\_bdy}.
 Each boundary set can be either defined as a series of straight line segments directly in the namelist
-(\np[=.false.]{ln_coords_file}{ln\_coords\_file}, and a namelist block \forcode{&nambdy_index} must be included for each set) or read in from a file (\np[=.true.]{ln_coords_file}{ln\_coords\_file}, and a ``\textit{coordinates.bdy.nc}'' file must be provided).
+(\np[=.false.]{ln_coords_file}{ln\_coords\_file}, and a namelist block \forcode{&nambdy_index} must be included for each set) or read in from a file (\np[=.true.]{ln_coords_file}{ln\_coords\_file}, and a ``\textit{coordinates.bdy.nc}'' file must be provided for each bdy segment).
 The coordinates.bdy file is analagous to the usual \NEMO\ ``\textit{coordinates.nc}'' file.
-In the example above, there are two boundary sets, the first of which is defined via a file and
-the second is defined in the namelist.
-For more details of the definition of the boundary geometry see section \autoref{subsec:LBC_bdy_geometry}.
+In the example above, there are two boundary sets, the first of which is defined via a file (namelist \ref{lst:nambdy}) and
+the second is defined through namelist parameters choice (namelist \ref{lst:nambdy_index}).
+For more details of the definition of the boundary geometry and coordinate files see section \autoref{subsec:LBC_bdy_geometry}.
 
 For each boundary set a boundary condition has to be chosen for the barotropic solution
 (``u2d'':sea-surface height and barotropic velocities), for the baroclinic velocities (``u3d''),