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/spm/toolbox/dcm_meeg
    
    the code of the file until where you have to start completion: function [x,M] = spm_x_mfm(P)
% Initialise 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)
%

    
function [x,M] = spm_x_mfm(P)
% Initialise 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)
%__________________________________________________________________________
 
% Karl Friston
% Copyright (C) 2005-2022 Wellcome Centre for Human Neuroimaging

 
% 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) + 1/8;
x{1}(:,:,1) = -70;
x{2}        = zeros(3,3,ns,np);
for i = 1:ns
    for j = 1:np
        x{2}(:,:,i,j) = diag([32, 1/32, 1/32]);
    end