gaussian.m

%#ok<*GVMIS>
%#ok<*NASGU>
global seq
global index
global f_inverse
global ky

N=1024;
n=log2(N);

seq=zeros(1,N);
index=1;

SNRdB=1;
SNR=10.^(SNRdB./10);
sigma_square=1/(SNR);

ky=keys(f_inverse);

temp=reli(2/sigma_square,0,n);
plot(1:N,exp(-0.25.*seq),'LineStyle','none','Marker','.');
xlabel('Channel Index');
ylabel('Bhattacharya Parameter Z(W)');
title('Bhattacharya Parameter of channels after Channel Polarization');
ylim([0 1]);
xlim([1 N]);

function r=reli(x,d,n)
    global seq
    global index
    global f_inverse
    global ky

    if d==n
        seq(index)=x;
        index=index+1;
        r=0;
    else 
        tempX=round(x*100)/100;
        disp(tempX);
        val=1-(1-real(f(tempX)))^2;
        val=round(val*100)/100;
        [~,ind] = min(abs(ky-val));

        disp(ky(ind));
        left=reli(f_inverse(ky(ind)),d+1,n);
        right=reli(2*x,d+1,n);
        r=0;
    end
end