log2(0)=-inf problem

Hallo,

my problem is that i want to set the quantity log2(0), so as log2(0)==0 {normally it is log2(0)==-inf}. is there a simple way to do this?

Thanks you in advance.

Answer 1

[Sean de Wolski]

Write your own log2 and call it:

function out = mylog2(in)
  out = log2(in);
  out(~in) = 0;
end

Add the F/E output options if desired.

It would be very dangerous to overload this function since it's probably used elsewhere.

[Matt Tearle]

Or, post process: y = log2(x); y(isinf(y)) = 0;

Am I suggesting some logical indexing? Why, yes, I think I am!

[Sean de Wolski]

x = [0 inf -inf 3];

[Matt Tearle]

y(isinf(y)&~isinf(x)) = 0

[Sean de Wolski]

I'm holding to ~x, logical and foolproof, no, doh! can't convert nan to logical arghh...

x==0