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+/ .*

Improved

initial writing: 2007-01-24
last updated: 2007-01-24


The dyad x +/ .* y has been made more efficient in space on rational or extended integer arguments. (There is little or no change in time.) The following benchmarks demonstrate the improvement:

x=. (s ?@$ 100) %&x: 1+s ?@$ 100 [ s=. 43, n
y=. (s ?@$ 100) %&x: 1+s ?@$ 100 [ s=.  n,61

ts=: 6!:2 , 7!:2@]  NB. time and space
ts 'x +/ .* y'
n       J 6.02    J 6.01    Ratio
10  0.822502 5.16224e5  0.817593 4.22816e6 0.99  8.19
20  2.696909 8.13696e5  2.681346 8.19059e6 0.99 10.07
40  8.248297 1.14067e6  8.108024 1.59593e7 0.98 13.99
80 22.977182 1.53427e6 23.566001 3.10102e7 1.03 20.21



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