Re: Power of two round up.

[Dominus]

I'm amazed at how clever this is, and I'm going to use it in my program. Thanks a lot.

[I0]

Although it's a technique more appropriate in a C program. In Perl, log($_)/log(2) benchmarks faster. (assuming it rounds properly at the boundaries)
Update: My earlier timethese qq{} may have been misleading. With timethese sub{} the | >> method comes out faster

[Dominus]

Sure, because it has to dispatch many fewer opcodes. But if I had wanted to use the log₂ x solution, I wouldn't have asked in the first place. Floating-point arithmetic gives me the heebie-jeebies.

[I0]

Floating-point gives me heebie-jeebies too. (in fact, a floating conversion seems to be what makes the |>> method fail for @_ = (0)
--then again, log(0) doesn't work either, and the |>> method does work for @_=(0) if you use integer;)
P.S. Why does an opcode fetch take longer than a transcendental function? I'm sure that part of the interpreter must have been fully optimized.