find all multiplicands and multipliers for a number

[Paul Rubin]

Dave Angel <davea at davea.name> writes:
>>          if x < 1e9:
> Now 10**9 is way below either limit of floating point. 

The idea was just to get rid of the case where c (further down in the
code) ends up being a negative number.  Floating point works fine for
numbers that small.

> And I can't figure out your code at this hour of night, but it's much
> more complicated than Newton's method would be anyway.

What I posted is just straightforward arithmetic.  I'd expect Newton's
method to be more complicated if you want to bound the error carefully
and make sure it is non-negative.  Maybe I'm wrong about that though.

Note my comment "d is between 10 and 11" is slightly inaccurate.  d can
in some cases be slightly above 11 but that is fine.