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: spm_diff_all.m
    path of file: ./repos/malini/Codes/deconvolution - model/spm8/toolbox/DEM
    
    the code of the file until where you have to start completion: function [varargout] = spm_diff_all(varargin)
% matrix high-order numerical differentiation
% FORMAT [dfdx] = spm_diff(f,x,...,n)
% FORMAT [dfdx] = spm_diff(f,x,...,n,V)
% FORMAT [dfdx] = spm_diff(f,x,...,n,'q')
%
% f      - [inline] function f(x{1},...)
% x      - input argument[s]
% n      - arguments to differentiate w.r.t.
%
% V      - cell array of matrices that allow for differentiation w.r.t.
% to a linear transformation of the parameters: i.e., returns
% 
% df/dy{i};    x = V{i}y{i};    V = dx(i)/dy(i)
%
% q      - flag to preclude default concatenation of dfdx
%

    
function [varargout] = spm_diff_all(varargin)
% matrix high-order numerical differentiation
% FORMAT [dfdx] = spm_diff(f,x,...,n)
% FORMAT [dfdx] = spm_diff(f,x,...,n,V)
% FORMAT [dfdx] = spm_diff(f,x,...,n,'q')
%
% f      - [inline] function f(x{1},...)
% x      - input argument[s]
% n      - arguments to differentiate w.r.t.
%
% V      - cell array of matrices that allow for differentiation w.r.t.
% to a linear transformation of the parameters: i.e., returns
% 
% df/dy{i};    x = V{i}y{i};    V = dx(i)/dy(i)
%
% q      - flag to preclude default concatenation of dfdx
%
% dfdx          - df/dx{i}                     ; n =  i
% dfdx{p}...{q} - df/dx{i}dx{j}(q)...dx{k}(p)  ; n = [i j ... k]
%
%
% - a cunning recursive routine
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging
 
% Karl Friston
% $Id: spm_diff_all.m 4146 2010-12-23 21:01:39Z karl $
 
% create inline object
%--------------------------------------------------------------------------
f     = varargin{1};
 
% parse input arguments
%--------------------------------------------------------------------------
if iscell(varargin{end