[Haskell-cafe] Performance help

Justin Bailey jgbailey at gmail.com
Tue Nov 13 17:45:33 EST 2007

On Nov 13, 2007 2:21 PM, Ryan Ingram <ryani.spam at gmail.com> wrote:
> Never mind, I realized this is a ring buffer with `mod` s.   That's another
> slow operation when you're doing code as tight as this.  If you can
> guarantee the ring is a power of 2 in size you can use a mask instead, or
> use my original suggestion of deriving rules from the previous rule and the
> new bit; the initial state is determined by the last bits in the buffer and
> you never wrap.

I can't guarantee the ring is a power of 2 but do you feel like
explaining the mask suggestion anyways?

Thanks for the bits suggestion - I'll see if that helps performance at
all. It looks like you have to be very careful in which concrete type
you choose or you'll get a lot of  conversion going on.


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