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f/
on Sparse Arguments Improved
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initial writing: 2001-07-29 last updated: 2004-10-26
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The monads f/ on sparse arguments have been
made more efficient in time and space.
The following table compares the time and space required
for +/s and +/"1 s
for sparse s of various shapes.
s=: 1 $. shape
r=: ?. 1e5 $ 1e6
i=: ?. (1e5,#$s) $ $s
s=: r (<"1 i)}s
ts=: 6!:2 , 7!:2@] NB. time and space
ts '+/ s'
ts '+/"1 s'
Shape |
Expression |
J 5.01 | |
J 4.06 | |
Ratio |
10 10 10 10 1e6 |
+/ s |
0.237968 | | 3802752 | |
0.328043 | | 12846848 | |
1.38 | | 3.38 |
|
+/"1 s |
0.025751 | | 526144 | |
0.191156 | | 3229632 | |
7.42 | | 6.14 |
1e6 10 10 10 10 |
+/ s |
0.346326 | | 1050432 | |
0.445293 | | 9520896 | |
1.29 | | 9.06 |
|
+/"1 s |
0.051208 | | 3278656 | |
0.206031 | | 6555584 | |
4.02 | | 2.00 |
2 10 10 10 10 1e6 |
+/ s |
0.225852 | | 3802752 | |
0.430299 | | 21171776 | |
1.91 | | 5.57 |
|
+/"1 s |
0.037085 | | 919360 | |
0.221206 | | 3704768 | |
5.96 | | 4.03 |
1e6 10 10 10 10 2 |
+/ s |
0.362589 | | 1443648 | |
0.475774 | | 14190336 | |
1.31 | | 9.83 |
|
+/"1 s |
0.056411 | | 3278656 | |
0.421492 | | 21172160 | |
7.47 | | 6.46 |
4$1e6 |
+/ s |
0.299557 | | 3802752 | |
0.381521 | | 12846848 | |
1.27 | | 3.38 |
|
+/"1 s |
0.044956 | | 3278656 | |
0.180579 | | 6555584 | |
4.02 | | 2.00 |
8$1e3 |
+/ s |
0.338152 | | 5900096 | |
0.551470 | | 21235712 | |
1.63 | | 3.60 |
|
+/"1 s |
0.078596 | | 5376000 | |
0.464777 | | 10750080 | |
5.91 | | 2.00 |
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