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_fp_fun.m
    path of file: ./repos/malini/Codes/deconvolution - model/spm8
    
    the code of the file until where you have to start completion: function [y] = spm_fp_fun(P,M,U)
% returns the predicted diffusion for Fokker Planck optimisation
% FORMAT [y] = spm_fp_fun(P,M,U)
%
% P = spm_vec(P)
% P.a - 0th order coefficients of force
% P.b - 1st order coefficients of force
% P.c - 2nd order coefficients of force
%
% M   - model specifying flow(M(1).f; density M(1).fq and support M(1).X
% U   - inputs
%
% y   - prediction
%__________________________________________________________________________

    
function [y] = spm_fp_fun(P,M,U)
% returns the predicted diffusion for Fokker Planck optimisation
% FORMAT [y] = spm_fp_fun(P,M,U)
%
% P = spm_vec(P)
% P.a - 0th order coefficients of force
% P.b - 1st order coefficients of force
% P.c - 2nd order coefficients of force
%
% M   - model specifying flow(M(1).f; density M(1).fq and support M(1).X
% U   - inputs
%
% y   - prediction
%__________________________________________________________________________
% Copyright (C) 2005 Wellcome Trust Centre for Neuroimaging
 
% Karl Friston
% $Id: spm_fp_fun.m 2030 2008-09-02 18:28:40Z karl $
 
% default: first level of hierarchical model
%--------------------------------------------------------------------------
M   = M(1);
 
% default expansion point for inputs
%--------------------------------------------------------------------------
try
    u = U.u;
catch
    u = sparse(M.m,1);
end