One thing you might try (though this may also fail due to floating point errors) is multiplying your number by a few hundred before taking the log. Then subtracting from the result to account for the initial magnification. 
log(a*b) = log a + log b

log10 1000 = 3
log10 6 = 0.77815125
log10 6000 = 3.77815125
...

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UPDATE: Although this makes me think we ought to have a Math::SmallRat and SmallFloat. PDL or Math::FixedPrecision might also work.

UPDATE: Apparently Math::BigFloat is just a bit of a slight misnomer. It's not just for BIG numbers. The Big imples a large number of bits assigned to store the number.

--
I'm not belgian but I play one on TV.

In reply to Re: Very small numbers by belg4mit
in thread Very small numbers by Win

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