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: dartel3.m
    path of file: ./repos/malini/Codes/deconvolution - model/spm8/toolbox/DARTEL
    
    the code of the file until where you have to start completion: function varargout = dartel3(varargin)
% DARTEL 3D image registration stuff
%
%_______________________________________________________________________
%
% FORMAT v = dartel3(v,g,f,param)
% v     - flow field n1*n2*n3*3 (single precision float)
% g     - first image n1*n2*n3*n4 (single precision float)
% f     - second image n1*n2*n3*n4 (single precision float)
% param - 9 parameters (settings)
%         - [
    
function is the sum of squares difference.  Alternatively, images can be
% vector fields, in which case the objective function is the sum of squares
% difference between each scalar field + the sum of squares difference
% between one minus the sum of the scalar fields.
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%_______________________________________________________________________
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% FORMAT v = dartel3('cgs',A, b, param)
% v     - the solution
% A     - parameterisation of 2nd derivatives
% b     - parameterisation of first derivatives
% param - 6 parameters (settings)
%         - [1] Regularisation type, can take values of
%           - 0 Linear elasticity
%           - 1 Membrane energy
%           - 2 Bend