Variation on the copy2 theme: overshoot and then crop.
copy2a=: 4 : '(x*{:$y) {."1 ,.~^:(>.2^.1>.x) y'
2000 (copy -: copy2a) b
1
ts '2000 copy2a b'
0.000196394 28352
----- Original Message -----
From: "Roger Hui" <[EMAIL PROTECTED]>
To: "Programming forum" <[email protected]>
Sent: Saturday, March 18, 2006 8:59 AM
Subject: Re: [Jprogramming] Different(and maybe more elegant) ways of copying?
Yet another alternative is powers of the monad ,.~ .
If x is a power of 2 then the method is really short and fast.
If x is not a power of 2 then more code is required.
(1024 copy b)-: ,.~^:10 b
1
ts=: 6!:2 , 7!:[EMAIL PROTECTED]
ts '1024 copy b'
0.000481905 17920
ts ',.~^:10 b'
8.63238e_5 13248
copy2=: 4 : '> ,.&.>/ ,.~&.>^:(I.|.#:x) <y'
2000 (copy -: copy1) b
1
2000 (copy -: copy2) b
1
ts '2000 copy b'
0.000918273 25664
ts '2000 copy1 b'
0.000234387 41984
ts '2000 copy2 b'
0.000215949 29056
----- Original Message -----
From: "Roger Hui" <[EMAIL PROTECTED]>
To: "Programming forum" <[email protected]>
Sent: Saturday, March 18, 2006 8:47 AM
Subject: Re: [Jprogramming] Different(and maybe more elegant) ways of copying?
An alternative is to use indexing:
copy1=: ([ (* $ [EMAIL PROTECTED]) {:@[EMAIL PROTECTED]) {"1 ]
1000 (copy -: copy1) b
1
----- Original Message -----
From: "June Kim" <[EMAIL PROTECTED]>
To: "Programming forum" <[email protected]>
Sent: Saturday, March 18, 2006 8:32 AM
Subject: [Jprogramming] Different(and maybe more elegant) ways of copying?
b=. 2 2 $'abcd'
copy=.13 : ',./ > x $< y ' NB. copies the box side by side
3 copy b
ababab
cdcdcd
4 copy b
abababab
cdcdcdcd
Maybe, I could use under(as in 13 : ',./ (x&$)&.< y') but the final
form isn't tacit, which is not a big problem; however I'm interested
in knowing other possibilities.
Any suggestions?
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
