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_BMS_bor.m
    path of file: ./repos/spm
    
    the code of the file until where you have to start completion: function [bor,F0,F1] = spm_BMS_bor(L,posterior,priors,C)
% Compute Bayes Omnibus Risk
% FORMAT [bor,F0,F1] = spm_BMS_bor(L,posterior,priors,C)
%
% L         Log model evidence table (models x  subjects)
% posterior .a model counts, .r model-subject probs
% priors    .a model counts
% C         if this field is specified then BOR under family prior 
%           is computed, otherwise BOR under model prior is computed.

    
function [F0m,F0f] = FE_null (L,options)
% Free energy of the 'null' (H0: equal frequencies)
%
% F0m       Evidence for null (ie. equal probs) over models 
% F0f       Evidence for null (ie. equal probs) over families
%
% This routine derives from the VBA_groupBMC function
% of the VBA toolbox http://code.google.com/p/mbb-vb-toolbox/ 
% written by Lionel Rigoux and J. Daunizeau
%
% See Equation A.17 in Rigoux et al.

[K,n] = size(L);
if options.families
    f0 = options.C*sum(options.C,1)'.^-1/size(options.C,2);
    F0f = 0;
else
    F0f = [];
end