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: grid_graph.m
    path of file: ./repos/CBIG/external_packages/matlab/default_packages/matlab_bgl_mac64
    
    the code of the file until where you have to start completion: function [A coords] = grid_graph(varargin)
% GRID_GRAPH Generate a grid graph or hypergrid graph 
% 
% [A xy] = grid_graph(m,n) generates a grid graph with m vertices along the
% x axis and n vertices along the y axis.  The xy output gives the 2d
% coordinates of each vertex. 
% [A xyz] = grid_graph(m,n,k) generates a grid graph with m vertices along
% the x axis, n vertices along the y axis, and k vertices along the z axis.
% The xyz output gives the 3d coordinates of each vertex.
% [A X] = grid_graph(d1, d2, ..., dk) generates a hypergrid graph in k
% dimensions with d1 vertices along dimension 1, d2 vertices along
% dimension 2, ..., and dk vertices along the final dimension.  The X
% output gives the k dimensional coordinates of each vertex.
% [A X] = grid_graph([d1, d2, ..., dk]) is an alternate input scheme.
%
% Example:

    
function [A coords] = grid_graph(varargin)
% GRID_GRAPH Generate a grid graph or hypergrid graph 
% 
% [A xy] = grid_graph(m,n) generates a grid graph with m vertices along the
% x axis and n vertices along the y axis.  The xy output gives the 2d
% coordinates of each vertex. 
% [A xyz] = grid_graph(m,n,k) generates a grid graph with m vertices along
% the x axis, n vertices along the y axis, and k vertices along the z axis.
% The xyz output gives the 3d coordinates of each vertex.
% [A X] = grid_graph(d1, d2, ..., dk) generates a hypergrid graph in k
% dimensions with d1 vertices along dimension 1, d2 vertices along
% dimension 2, ..., and dk vertices along the final dimension.  The X
% output gives the k dimensional coordinates of each vertex.
% [A X] = grid_graph([d1, d2, ..., dk]) is an alternate input scheme.
%
% Example:
%   [A xy] = grid_graph(5,10);
%   gplot(A,xy);
%   A = grid_graph(2*ones(1,10)); % compute 10d hypercube

% David Gleich
% Copyright, Stanford University, 2007-2008

%% History
%  2007-07-13: Initial version
%%

k = length(varargin);

if k==1 && numel(varargin{1}) > 1
    varargin = num2cell(varargin{1});
    k = length(varargin);
else
    if any(cellfun('prodofsize',varargin)~=1)
        error('matlab_bgl:invalidArgument',...
            'please specific the size of dimension in the arguments');
    end