why compression doesn't perfectly even out entropy
Perry E. Metzger
perry at piermont.com
Fri Apr 19 00:31:18 PDT 1996
Hal writes:
> The first is whether this mysterious black box, the entropy estimator,
> is really possible. In practice the only way to know how much entropy
> you've gotten is to have a model for how the data is being generated,
> and to deduce from that an estimate of the entropy rate. So the entropy
> estimator can't be a general-purpose calcluation, but it must be one
> which is specifically chosen, developed and tuned for the specific source
> of entropy you are dealing with.
I couldn't possibly say that better. Its the central point.
> So I think the lesson is that there is only one way to estimate entropy,
> and that is to study your source. I have to agree with Perry that this
> filtering concept is not the way to go. It is a red herring that lures
> you in the direction of automatic entropy estimation, and that is really
> not safe.
Thank you; you are making the point far better than I did.
.pm
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