You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: plot_boundary.m
    path of file: ./repos/tracacode/1911-COAWST/script/mfiles/rutgers/boundary
    
    the code of the file until where you have to start completion: function plot_boundary(Gname, Bname, Vname, Tindex)

%
% PLOT_BOUNDARY:  Plots requested ROMS variable from boundary NetCDF file
%

    
function plot_boundary(Gname, Bname, Vname, Tindex)

%
% PLOT_BOUNDARY:  Plots requested ROMS variable from boundary NetCDF file
%
% B=plot_boundary(Gname, Bname, Vname, Tindex)
%
% This function plots requested ROMS variable from input lateral
% boundary NetCDF file. This function is very useful for browsing
% 3D lateral boundary conditions for ROMS in a vertical slab. The
% location of the minumum is marked with a filled magenta circle
% whereas the  maximum is marked with a filled magenta square.
%
% On Input:
%
%    Gname         ROMS Grid NetCDF file/URL name (string)
%              or, an existing ROMS grid structure (struct array)
%
%    Bname         ROMS boundary NetCDF file/URL name (string)
%
%    Vname         ROMS state variable name to process (string)
%
%    Tindex        Time record index used to process (scalar)
%


% svn $Id: plot_boundary.m 938 2019-01-28 06:35:10Z arango $
%=========================================================================%
%  Copyright (c) 2002-2019 The ROMS/TOMS Group                            %
%    Licensed under a MIT/X style license                                 %
%    See License_ROMS.txt                           Hernan G. Arango      %
%=========================================================================%

% Initialize.

Tname = [];
Tsize = 0;

% Set ROMS Grid structure.
  
if (~isstruct(Gname))
  G = get_roms_grid(Gname,Bname);
else
  G = Gname;
end