From: "Simon Kröger" <SimonKroeger@...>
Date: 2006-08-08T05:53:08+09:00
Subject: Re: nextPowerOf2(n)

Rick DeNatale wrote:
> I hope that this doesn't offend anyone, but in the spirit of test
> infection...
> 
> I actually took the various suggestions and wrote test cases.  Here's
> my file "next_power_of_2.r b" which defines either methods on Integer,
> or a class with a next_power_of_2() class method, following the
> various suggestions,  I did give these methods a consistent name
> following Ruby naming standards.

...


> This really isn't surprising, since floating point arithmetic only
> approximates real arithmetic using real numbers.
> 
> My original intention was to benchmark the various suggestions, but
> since you can get the wrong answers with arbitrarily fast code, I
> don't think that it matters much.

Hmm, what about:

def next_power_of_2(n)
  throw 'eeek' if n < 0
  return 1 if n < 2
  1 << (n-1).to_s(2).size
end

?

cheers

Simon