JESUS CHRIST!
What the hell just happened? I used clojure 1.5 alpha 3 that has the new
reducers and now i get back the same result in 3 seconds!!!!
HOW ON EARTH IS THAT POSSIBLE? I mean i've watched the videos but i
would never expect so much performance increase!!! what is happening? Is
my algorithm completely wrong? this is scary stuff...
the bad news is that i always get the same answer regardless of the
depth...also something suspicious is the fact the no matter the depth
the r/map returns in constant time! something smells here!
Jim
On 18/08/12 19:24, Jim - FooBar(); wrote:
On 18/08/12 13:57, Michael Gardner wrote:
Until the reducers library is ready, you could try something like
this (no guarantees that this is an optimal implementation!):
(defn with-thread-pool* [num-threads f]
(let [pool (java.util.concurrent.Executors/newFixedThreadPool
num-threads)]
(try (f pool)
(finally
(when pool (.shutdown pool))))))
(defmacro with-thread-pool [[name num-threads] & body]
`(with-thread-pool* ~num-threads (fn [~name] ~@body)))
(defn pmap-pool [f coll]
(with-thread-pool [pool (.. Runtime getRuntime availableProcessors)]
(doall
(map #(.get %)
(.invokeAll pool
(map (partial partial f)
coll))))))
Hi Michael,
Unfortunately I get exactly the same performance with pmap when using
the above code... and again 2 of my cpus are sitting around waiting!
If use pmap or map-pool on all levels i get almost 100% utilisation of
cpu but nothing useful happens!!! anyway, I'll have a look at reducers!
thanks for the snippet anyway!
Jim
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