How to work with arrays with values of Log(0)?

I am working with arrays that include zero values. One transformation I must do is apply logarithms to each value in the matrix. In the result, I need to do other operations but I have to skip the values that do not have a result of the logarithm. How can I do that?

Thanks

Answer 1

[David Hill]

a=log(initialArray);
idx=initialArray~=0;
a(idx)=5*a(idx);%other calculations only perform on non-zero values of initial array