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mfikes/Compare.md

Created April 23, 2015 17:47
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Compare perf of two ways to remove an element from vector by index
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Compare.md 
(defn remove-idx [coll idx] 
  (into (subvec coll 0 idx) (subvec coll (inc idx))))
(defn remove-idx' [coll idx] 
  (vec (concat (subvec coll 0 idx) (subvec coll (inc idx)))))

Remove an element from near beginning:

(defn run-bench [n]
  (let [v (vec (range n))]
    (quick-bench (remove-idx v 3))
    (quick-bench (remove-idx' v 3))))
              mean              mean
Vector size   remove-idx        remove-idx'
         10   559.869740 ns     867.888254 ns
        100    12.110264 µs       4.777121 µs
       1000   133.095287 µs      40.676972 µs
      10000     1.822973 ms     446.378637 µs

Remove an element from near end:

(defn run-bench [n]
  (let [v (vec (range n))]
    (quick-bench (remove-idx v (- n 3)))
    (quick-bench (remove-idx' v (- n 3)))))
              mean              mean
Vector size   remove-idx        remove-idx'
         10   336.695389 ns       1.309534 µs
        100   327.457512 ns      14.719970 µs
       1000   352.013322 ns     150.545199 µs
      10000   360.010662 ns       1.516899 ms
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