Greetings. I have a question about insert (/). I've been trying to
insert a simple verb (foo, below) into an array of randomly-chosen
numbers. The verb performs addition--but with the result clamped to
1-100. I need to know at what point the sum (which will be bouncing
around because some of the random numbers are negative) hits 100. (I'm
willing to use i. for that; I don't mind if I generate extra,
unnecessary random numbers. That's not the problem at this point.)
foo =: 4 : 0
NB. x is a total
NB. y is an increment
NB. return a new total 1..100
1 >. (x + y) <. 100
)
load 'plot'
plot k=.foo/\d=.(?200$6) { _1 2 _3 4 _5 6
You wind up with a very strange plot: Long sequences of identical
numbers, which can't(?) happen given that none of the incremental random
numbers is zero. Also it slopes upward almost exclusively.
I'll guess at the solution: / is implemented in parallel, not
sequentially (in some sense--I know my CPU is actually sequential). So
I'm not proceeding sedately from number to number, left to right; I'm
actually getting some weird artifact of parallelism, which can't handle
the clipping properly since it's working with partial, independently
clipped sums. (If that's the case, I should be chastised for thinking
sequentially, which I believe is a sin in J.) Or something. Any help
greatly appreciated.
Ed
Ed Gottsman
Accenture Technology Labs
161 N. Clark St.
Chicago, IL 60601
Cell: 847-274-0320
AIM: gottsman63
[EMAIL PROTECTED]
Blog: http://www.accenture.com/gottsman
<http://www.accenture.com/gottsman>
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