shannon编码

function [W,L,q] =shannon(p)

    if (length(find(p<=0))~=0)
         error('Not a prob.vector.negative component');
    end

    if (abs(sum(p)-1)>10e-10)
          error('Not a prob.vetor.component do not add up to 1')   
    end
[p,x]=array(p);

l=ceil(-log2(p));

P(l)=0;
n=length(p);
for i=2:n
         P(i)=P(i-1)+p(i-1);
end

for i=1:n
      for j=1:l(i)
              temp(i,j)=floor(P(i)*2);
              P(i)=P(i)*2-temp(i,j);
      end
end

for i=1:n
      for j=1:l(i)
              if (temp(i,j)==0)
                   W(i,j)=48;