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_deformations.m
    path of file: ./repos/spm
    
    the code of the file until where you have to start completion: function out = spm_deformations(job)
% Various deformation field utilities
% FORMAT out = spm_deformations(job)
% job - a job crea
    
function Def = affine(y,M)
%==========================================================================
function Def = affine(y,M)
Def          = zeros(size(y),'single');
Def(:,:,:,1) = y(:,:,:,1)*M(1,1) + y(:,:,:,2)*M(1,2) + y(:,:,:,3)*M(1,3) + M(1,4);
Def(:,:,:,2) = y(:,:,:,1)*M(2,1) + y(:,:,:,2)*M(2,2) + y(:,:,:,3)*M(2,3) + M(2,4);
Def(:,:,:,3) = y(:,:,:,1)*M(3,1) + y(:,:,:,2)*M(3,2) + y(:,:,:,3)*M(3,3) + M(3,4);


%==========================================================================
% function Def = identity(d,M)
%==========================================================================
function Def = identity(d,M)
[y1,y2]   = ndgrid(single(1:d(1)),single(1:d(2)));
Def       = zeros([d 3],'single');
for y3=1:d(3)
    Def(:,:,y3,1) = y1*M(1,1) + y2*M(1,2) + (y3*M(1,3) + M(1,4));
    Def(:,:,y3,2) = y1*M(2,1) + y2*M(2,2) + (y3*M(2,3) + M(2,4));
    Def(:,:,y3,3) = y1*M(3,1) + y2*M(3,2) + (y3*M(3,3) + M(3,4));
end