matlab - How can I vectorize the entropy calculation? -

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i trying entropy every column, matrix looks this: 

0.5 0.3333 0.2   0   0.3333 0.4   0.5 0.3333 0.4

every column add one, however, there's zeros in matrix, if log2(arr(i,:)), there -inf in result whole thing won't work
in practice have huge matrix, want program run fast, there work around?
here's solution, works fast p .* log2(p)?

    log2p = log2(p);     log2p(log2p==-inf)=0;     entropy = entropy - p .* log2p;

in matlab 0^0 equal 1. , since log2(1)==0, can use , rewrite entropy function as

p.*log2(p) = log2(p.^p)

then example get

>> log2(p.^p)  ans =     -0.5000   -0.5283   -0.4644          0   -0.5283   -0.5288    -0.5000   -0.5283   -0.5288

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