OK, it appears defrecord suffers from a problem that used to plague Scala
case classes as well - http://issues.scala-lang.org/browse/SI-2537.
David
On Thu, Oct 24, 2013 at 8:08 AM, Paul Butcher <p...@paulbutcher.com> wrote:
> On 23 Oct 2013, at 18:37, David Nolen <dnolen.li...@gmail.com> wrote:
>
> The problem here is that you're not following your Scala solution closely
> enough. I suspect if you used defrecords to represent the pieces the way
> that you used a class in Scala you can avoid the number of collisions for
> larger problems.
>
> Not tested much but I tried something like the following and I no longer
> see hash collisions dominating in YourKit:
>
>
> It would be lovely if it was that easy, David. However, I still see lots
> of hash collisions when using records. Here's a portion of the output from
> an implementation that's instrumented to print hash codes, similar to what
> Andy did with the vector-based implementation:
>
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 2]}
> #chess_clojure.core.Piece{:name :B, :pos [1 5]}
> #chess_clojure.core.Piece{:name :N, :pos [0 1]}
> #chess_clojure.core.Piece{:name :R, :pos [8 4]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :N, :pos [0 4]}
> #chess_clojure.core.Piece{:name :Q, :pos [3 3]}
> #chess_clojure.core.Piece{:name :B, :pos [1 0]}
> #chess_clojure.core.Piece{:name :R, :pos [8 5]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :N, :pos [0 4]}
> #chess_clojure.core.Piece{:name :Q, :pos [3 3]}
> #chess_clojure.core.Piece{:name :B, :pos [1 4]}
> #chess_clojure.core.Piece{:name :R, :pos [8 1]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :N, :pos [0 3]}
> #chess_clojure.core.Piece{:name :Q, :pos [3 4]}
> #chess_clojure.core.Piece{:name :B, :pos [1 0]}
> #chess_clojure.core.Piece{:name :R, :pos [8 5]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :N, :pos [0 3]}
> #chess_clojure.core.Piece{:name :Q, :pos [3 5]}
> #chess_clojure.core.Piece{:name :B, :pos [1 0]}
> #chess_clojure.core.Piece{:name :R, :pos [8 4]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :R, :pos [0 3]}
> #chess_clojure.core.Piece{:name :Q, :pos [4 2]}
> #chess_clojure.core.Piece{:name :B, :pos [1 0]}
> #chess_clojure.core.Piece{:name :N, :pos [8 0]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :R, :pos [0 3]}
> #chess_clojure.core.Piece{:name :Q, :pos [3 4]}
> #chess_clojure.core.Piece{:name :B, :pos [1 5]}
> #chess_clojure.core.Piece{:name :N, :pos [8 0]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 2]}
> #chess_clojure.core.Piece{:name :B, :pos [1 5]}
> #chess_clojure.core.Piece{:name :R, :pos [0 0]}
> #chess_clojure.core.Piece{:name :N, :pos [8 5]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [4 2]}
> #chess_clojure.core.Piece{:name :R, :pos [1 1]}
> #chess_clojure.core.Piece{:name :B, :pos [0 5]}
> #chess_clojure.core.Piece{:name :N, :pos [8 5]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 2]}
> #chess_clojure.core.Piece{:name :R, :pos [1 1]}
> #chess_clojure.core.Piece{:name :B, :pos [0 4]}
> #chess_clojure.core.Piece{:name :N, :pos [8 5]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :R, :pos [0 3]}
> #chess_clojure.core.Piece{:name :Q, :pos [3 4]}
> #chess_clojure.core.Piece{:name :B, :pos [1 0]}
> #chess_clojure.core.Piece{:name :N, :pos [8 5]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 4]}
> #chess_clojure.core.Piece{:name :R, :pos [1 1]}
> #chess_clojure.core.Piece{:name :B, :pos [0 5]}
> #chess_clojure.core.Piece{:name :N, :pos [8 2]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 5]}
> #chess_clojure.core.Piece{:name :R, :pos [1 1]}
> #chess_clojure.core.Piece{:name :B, :pos [0 4]}
> #chess_clojure.core.Piece{:name :N, :pos [8 2]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 4]}
> #chess_clojure.core.Piece{:name :B, :pos [1 5]}
> #chess_clojure.core.Piece{:name :R, :pos [0 2]}
> #chess_clojure.core.Piece{:name :N, :pos [8 1]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 5]}
> #chess_clojure.core.Piece{:name :B, :pos [0 4]}
> #chess_clojure.core.Piece{:name :R, :pos [1 2]}
> #chess_clojure.core.Piece{:name :N, :pos [8 1]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 4]}
> #chess_clojure.core.Piece{:name :B, :pos [1 5]}
> #chess_clojure.core.Piece{:name :R, :pos [7 2]}
> #chess_clojure.core.Piece{:name :N, :pos [0 0]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [4 2]}
> #chess_clojure.core.Piece{:name :B, :pos [0 4]}
> #chess_clojure.core.Piece{:name :N, :pos [6 5]}
> #chess_clojure.core.Piece{:name :R, :pos [1 0]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [4 0]}
> #chess_clojure.core.Piece{:name :R, :pos [0 2]}
> #chess_clojure.core.Piece{:name :N, :pos [6 5]}
> #chess_clojure.core.Piece{:name :B, :pos [1 4]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [4 2]}
> #chess_clojure.core.Piece{:name :R, :pos [0 0]}
> #chess_clojure.core.Piece{:name :N, :pos [6 5]}
> #chess_clojure.core.Piece{:name :B, :pos [1 4]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [4 2]}
> #chess_clojure.core.Piece{:name :R, :pos [1 1]}
> #chess_clojure.core.Piece{:name :N, :pos [6 5]}
> #chess_clojure.core.Piece{:name :B, :pos [0 3]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :R, :pos [1 4]}
> #chess_clojure.core.Piece{:name :Q, :pos [3 3]}
> #chess_clojure.core.Piece{:name :N, :pos [6 5]}
> #chess_clojure.core.Piece{:name :B, :pos [2 0]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 4]}
> #chess_clojure.core.Piece{:name :B, :pos [1 0]}
> #chess_clojure.core.Piece{:name :R, :pos [7 2]}
> #chess_clojure.core.Piece{:name :N, :pos [0 5]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [4 1]}
> #chess_clojure.core.Piece{:name :N, :pos [7 3]}
> #chess_clojure.core.Piece{:name :R, :pos [1 5]}
> #chess_clojure.core.Piece{:name :B, :pos [0 3]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [4 1]}
> #chess_clojure.core.Piece{:name :R, :pos [1 2]}
> #chess_clojure.core.Piece{:name :N, :pos [7 3]}
> #chess_clojure.core.Piece{:name :B, :pos [2 0]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 4]}
> #chess_clojure.core.Piece{:name :R, :pos [1 1]}
> #chess_clojure.core.Piece{:name :N, :pos [7 3]}
> #chess_clojure.core.Piece{:name :B, :pos [0 3]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :R, :pos [1 4]}
> #chess_clojure.core.Piece{:name :Q, :pos [3 5]}
> #chess_clojure.core.Piece{:name :N, :pos [8 3]}
> #chess_clojure.core.Piece{:name :B, :pos [0 0]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 4]}
> #chess_clojure.core.Piece{:name :B, :pos [0 5]}
> #chess_clojure.core.Piece{:name :N, :pos [7 2]}
> #chess_clojure.core.Piece{:name :R, :pos [1 0]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 5]}
> #chess_clojure.core.Piece{:name :B, :pos [0 4]}
> #chess_clojure.core.Piece{:name :N, :pos [7 2]}
> #chess_clojure.core.Piece{:name :R, :pos [1 0]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 4]}
> #chess_clojure.core.Piece{:name :N, :pos [7 2]}
> #chess_clojure.core.Piece{:name :B, :pos [1 0]}
> #chess_clojure.core.Piece{:name :R, :pos [0 5]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 5]}
> #chess_clojure.core.Piece{:name :N, :pos [7 2]}
> #chess_clojure.core.Piece{:name :B, :pos [1 0]}
> #chess_clojure.core.Piece{:name :R, :pos [0 4]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [4 1]}
> #chess_clojure.core.Piece{:name :R, :pos [1 3]}
> #chess_clojure.core.Piece{:name :N, :pos [7 2]}
> #chess_clojure.core.Piece{:name :B, :pos [2 0]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 5]}
> #chess_clojure.core.Piece{:name :R, :pos [0 0]}
> #chess_clojure.core.Piece{:name :N, :pos [7 2]}
> #chess_clojure.core.Piece{:name :B, :pos [1 4]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 5]}
> #chess_clojure.core.Piece{:name :R, :pos [1 1]}
> #chess_clojure.core.Piece{:name :N, :pos [7 2]}
> #chess_clojure.core.Piece{:name :B, :pos [0 3]}}"
> "842565000: #{#chess_clojure.core.Piece{:name :Q, :pos [3 4]}
> #chess_clojure.core.Piece{:name :B, :pos [1 5]}
> #chess_clojure.core.Piece{:name :N, :pos [0 2]}
> #chess_clojure.core.Piece{:name :R, :pos [8 1]}}"
>
> --
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>
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