With a little help from POSIX, and remembering some basics about polyadic number systems, i.e. with the help of the natural logarithm, an IMHO straightforward implementation can be made: 

use POSIX qw(ceil);

sub powround { 
   my ( $x, $base ) = @_;
   return ( $base ** ceil(log($x)/log($base)));
}

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That is, ln(a) / ln(b) gives you the number of digits needed to represent the number a relative to the base b (and ln() is the natural logarithm, i.e. to the base e (Euler's number)).

Then round that up to the next greater or equal integer (POSIX::ceil), and exponentiate the base with it. Voilą, you have the next greater or equal power of the base.

p.s.: using `POSIX::ceil` covers all corner cases, whereas using `int(...) + 1` as suggested in previous responses, does not.

In reply to Re: Power of two round up. by c-alpha
in thread Power of two round up. by boo_radley

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