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_eeg_invertiter.m
    path of file: ./repos/spm
    
    the code of the file until where you have to start completion: function [Dtest,modelF,allF]=spm_eeg_invertiter(Dtest,Npatchiter,funcname,patchind)
%  Function to perform several MSP type inversions with different
%  pseudo-randomly selected priors- in this 
    
function call specified');
end

if nargin<4
    patchind=[];
end
if isempty(Npatchiter)
    Npatchiter=16;
end

if numel(Dtest)>1
    error('only works with single datasets at the moment');
end


val=Dtest{1}.val;


Nvert=size(Dtest{1}.inv{val}.mesh.tess_mni.vert,1);
Np=Dtest{1}.inv{val}.inverse.Np;

allF=zeros(Npatchiter,1);


fprintf('Checking leadfields');


[L Dtest{1}] = spm_eeg_lgainmat(Dtest{1});  % Generate/load lead field- this stops it being done at each iteration


if isempty(patchind)
    disp('Reseting random number seed ! and then generating random patch centres ');
    rand('state',0);
    
    %% make random patch centers, except on the first iteration when we keep to a fixed stepsize
    for f=1:Npatchiter
        tmp=randperm(Nvert);
        allIp(f).Ip=tmp(1:Np);
    end