need a function

[Max Alekseyev]

Take a look at:
http://aggregate.org/MAGIC/#Log2%20of%20an%20Integer
http://www.cs.utk.edu/~vose/c-stuff/bithacks.html#IntegerLogObvious
http://www.jjj.de/bitwizardry/bitwizardrypage.html
etc.

Regards,
Max

On Fri, Jun 13, 2008 at 11:09 PM, Brendan McKay <bdm at cs.anu.edu.au> wrote:
> Hi seqfans.  This little problem might amuse someone and the answer
> might even be useful.
>
> We are considering arithmetic in the non-negative integers mod 2^32.
> The problem is, define a function f(n) using only +-*/ (where / throws
> away the remainder) such that f(2^i) = i for i=0,1,...,31.
>
> If that is too onerous, you can also use bit-wise boolean operations.
>
> The corresponding problem for 2^64 is also of interest.
>
> Cheers, Brendan.
>