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~. Sparse Arguments |
initial writing: 2001-04-05 |
The monad ~. now supports sparse arguments.
For example:
] d=: ?. 15 2$4
0 3
1 2
0 0
2 2
3 1
2 3
0 0
2 2
0 1
0 1
2 2
3 3
2 0
2 1
2 3
s=: $. d
(~. s) -: ~. d
1
~.s
0 1 | 3
1 0 | 1
1 1 | 2
3 0 | 2
3 1 | 2
4 0 | 3
4 1 | 1
5 0 | 2
5 1 | 3
6 1 | 1
7 0 | 3
7 1 | 3
8 0 | 2
9 0 | 2
9 1 | 1
~. d
0 3
1 2
0 0
2 2
3 1
2 3
0 1
3 3
2 0
2 1
p=: ?.100$1e9
q=: (?.100$20){?.20 5$10
s=: q p}1 $. 1e9 5 ; 0 ; 2-2
$s
1000000000 5
t=: ~. s
$t
21 5
($t) -: $ ~.0,q
1
(2$.t) -: ,0
1
(3$.t) -: 0
1
(4$.t) -: ,. (i.#t)-.{.(i.1+#p) -. p
1
(5$.t) -: ~.q/:p
1