Fine comb reading the (nu)voc sparse pages doesn't indicate. Is it true
that only the leading dimensions of an array can be sparse? For example f
and g produce different results when the only difference between them is
the choice of sparse axis. Thanks, Dave.
f=: 4 : 0
i=. #y
lc=.(0,.~#\i.i) y} 1$.(x,2);1;0
tail=. {: y
lu=. tail { lc
while. i < x do.
tail=. ((0 ~: {:) { (0 , -/)) lu
i =. >: i
lu=. i , {. tail { lc
lc=. lu tail} lc
end.
tail
)
g=: 4 : 0
i=. #y
lc=.(0,.~#\i.i) y} 1$.(x,2);0;0
tail=. {: y
lu=. tail { lc
while. i < x do.
tail=. ((0 ~: {:) { (0 , -/)) lu
i =. >: i
lu=. i , {. tail { lc
lc=. lu tail} lc
end.
tail
)
10(f,g)1 2 3
0 6
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