help in modified matlab function

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kokomy 2016-12-25

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/318132-help-in-modified-matlab-function

编辑： per isakson 2016-12-25

hi, I want to modifie the methode of calcul

ll(mod_idx-idx+1,:) = log(sum(exp_mat((bitget(mapping,idx)==0),:),1)) ...
                    - log(sum(exp_mat((bitget(mapping,idx)==1),:),1));

in the following function matlab:

function ll = calc_ll(r,sigma_n2,constellation,mapping)
mod_idx = log2(length(constellation));
dist = zeros(2^mod_idx,length(r));
%
for idx = 1:(2^mod_idx)
        dist(idx,:) = (real(r) - (real(constellation(idx)))).^2 + (imag(r) - (imag(constellation(idx)))).^2;
end
exp_mat = exp(-1./sigma_n2.*dist);
ll = zeros(mod_idx,length(r));
for idx = 1:mod_idx
    ll(mod_idx-idx+1,:) = log(sum(exp_mat((bitget(mapping,idx)==0),:),1)) ... 
                        - log(sum(exp_mat((bitget(mapping,idx)==1),:),1));
end
ll=ll(:);
to this methode 
kappa = H_cli/P_cli;
%
%cli_r = P_cli*r.*(abs(r)<kappa)+H_cli*sign(r).*(abs(r)>=kappa);