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_x_mfm.m
    path of file: ./repos/malini/Codes/deconvolution - model/spm8/toolbox/dcm_meeg
    
    the code of the file until where you have to start completion: function [x,M] = spm_x_mfm(P)
% initialises a state structure for a mean field model
% FORMAT [x,M] = spm_x_mfm(P)
%
% P - parameter structure (encoding extrinsic connections)
% M - model structure
%
% x - states and covariances
% M - model structure
%
% x{1}(i,j,k)   - k-th state of i-th source in j-th population
% x{2}(i,j,k,l) - covariance of i-th and j-th state (k-th source in l-th
%                 population
%
%   population: 1 - excitatory spiny stellate cells (input cells)
%               2 - inhibitory interneurons
%               3 - excitatory pyramidal cells      (output cells)
%
%        state: 1 V  - voltage
%               2 gE - conductance (excitatory)
%               3 gI - conductance (inhibitory)
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging

    
function [x,M] = spm_x_mfm(P)
% initialises a state structure for a mean field model
% FORMAT [x,M] = spm_x_mfm(P)
%
% P - parameter structure (encoding extrinsic connections)
% M - model structure
%
% x - states and covariances
% M - model structure
%
% x{1}(i,j,k)   - k-th state of i-th source in j-th population
% x{2}(i,j,k,l) - covariance of i-th and j-th state (k-th source in l-th
%                 population
%
%   population: 1 - excitatory spiny stellate cells (input cells)
%               2 - inhibitory interneurons
%               3 - excitatory pyramidal cells      (output cells)
%
%        state: 1 V  - voltage
%               2 gE - conductance (excitatory)
%               3 gI - conductance (inhibitory)
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging
 
% Karl Friston
% $Id: spm_x_mfm.m 2393 2008-10-23 14:58:50Z karl $

 
% dimensions
%--------------------------------------------------------------------------
ns   = size(P.A{1},1);                           % number of sources
np   = 3;                                        % number of populations
 
% create (initialise voltage at -70mV)
%--------------------------------------------------------------------------
x{1}        = zeros(ns,np,3);
x{1}(:,:,1) = -70;
x{2}        = zeros(3,3,ns,np);
for i = 1:ns
    for j = 1:np
        x{2}(:,:,i,j) = eye(3,3)/128;
    end