Help / Release / J 4.06 / i. and i: Improved
< Help
Jump to navigation
Jump to search
>> << Pri JfC LJ Phr Dic Voc !: Rel NuVoc wd Help Release
|
i. and i: Improved |
initial writing: 2000-09-07 |
The dyads i. and i: now perform better on 2-byte items.
Timing comparisons are as follows:
timer=: 6!:2
x=: a.{~ ?(m,2)$#a.
y=: a.{~ ?(n,2)$#a.
timer 'x i. y'
m n J 4.06 J 4.05
50e3 0.2e6 0.0154528 44.4957517
50e3 0.4e6 0.0265048 88.4189361
50e3 0.6e6 0.0372575 133.1981282
50e3 0.8e6 0.0543974 174.9362201
50e3 1.0e6 0.0669739 220.2604263
100e3 0.2e6 0.0223838 0.0542809
100e3 0.4e6 0.0335774 0.0875835
100e3 0.6e6 0.0457131 0.1226720
100e3 0.8e6 0.0588443 0.1561371
100e3 1.0e6 0.0711710 0.1892570
150e3 0.2e6 0.0248805 0.0683701
150e3 0.4e6 0.0373640 0.1023264
150e3 0.6e6 0.0499153 0.1356423
150e3 0.8e6 0.0629233 0.1713201
150e3 1.0e6 0.0748855 0.2048698
200e3 0.2e6 0.0288456 0.0739032
200e3 0.4e6 0.0420858 0.1108959
200e3 0.6e6 0.0535643 0.1459794
200e3 0.8e6 0.0664509 0.1799809
200e3 1.0e6 0.0783569 0.2143956
250e3 0.2e6 0.0327544 0.0810555
250e3 0.4e6 0.0454164 0.1190137
250e3 0.6e6 0.0573341 0.1511932
250e3 0.8e6 0.0700455 0.1887692
250e3 1.0e6 0.0821040 0.2294093
300e3 0.2e6 0.0365066 0.1043462
300e3 0.4e6 0.0490369 0.1405653
300e3 0.6e6 0.0615740 0.1756094
300e3 0.8e6 0.0740457 0.2131410
300e3 1.0e6 0.0863883 0.2496350
As well, the hash function on integer vector arguments has been changed.
On “average” arguments, the time remains linear but is slower by
a factor of 1.5 to 2, but the chance of “bad” arguments with
quadratic time is reduced.
a=: 100000 ? 100000
b=: 50000 ? 50000
c=: , (i.1000)+"1 0 ] 1e8 * 1+i.4
e=: c ,a
f=: (-c),a
J 4.06 J 4.05
e i. b 0.112724 0.0714972
f i. b 0.108505 14.2669