(with apologies for piling on...)
Yep, apples and oranges: both have fruit DNA, just arranged differently...
R.E. Boss wrote:
I am not.
Its the same kind of fruit, only stored differently, as the following shows.
ps2 i.4 NB. your solution
++-+-+---+-+---+---+-----+-+---+---+-----+---+-----+-----+-------+
||3|2|2 3|1|1 3|1 2|1 2 3|0|0 3|0 2|0 2 3|0 1|0 1 3|0 1 2|0 1 2 3|
++-+-+---+-+---+---+-----+-+---+---+-----+---+-----+-----+-------+
ps4 4 NB. my solution
++-+---+-----+-------+
||0|0 1|0 1 2|0 1 2 3|
||1|0 2|0 1 3| |
||2|0 3|0 2 3| |
||3|1 2|1 2 3| |
|| |1 3| | |
|| |2 3| | |
++-+---+-----+-------+
So, contrary to what you write, its both "interesting" and "informative to
compare the time/space needed to compute them".
R.E. Boss
-----Oorspronkelijk bericht-----
Van: [EMAIL PROTECTED] [mailto:programming-
[EMAIL PROTECTED] Namens Roger Hui
Verzonden: dinsdag 14 augustus 2007 23:11
Aan: Programming forum
Onderwerp: Re: [Jprogramming] Power sets
You are comparing apples to oranges.
----- Original Message -----
From: "R.E. Boss" <[EMAIL PROTECTED]>
Date: Tuesday, August 14, 2007 13:37
Subject: RE: RE: [Jprogramming] Power sets
To: 'Programming forum' <[email protected]>
Since I was not talking about representations, but (different)
groupings (of
subsets) your first remark is highly irrelevant.
Your second remark is answered by the solution you gave.
ps3 is still a lot more efficient than ps2:
ts'ps2 ''abcdefghijklmnopqrst'''
1.3516162 90327552
ts'ps3 ''abcdefghijklmnopqrst'''
0.57262191 1.2099904e8
But improvement is still possible.
Using the idea of comb I constructed
ps4=: 3 : '(}:,;&.>@{:) (}:,
[:({.,<@([EMAIL PROTECTED],.&.>])@}.)[:,&.>/\.>@{:)^:y(y$<i.0
0)<@,<i.1 0' NB. line wrap!
and
ps4a=: ([:ps4 #) {&.> <@] NB. for nouns which are not an
integer atom
ts'ps4a ''abcdefghijklmnopqrst'''
0.37404972 1.2099936e8
(ps2-:&(\:~)[:;[:<"1&.>ps4a) 'abcdefghijklmnopqrst'
1
Further
ts 'ps2 i.20'
2.0541071 1.5356698e8
ts 'ps4 20'
0.21588886 63326336
([EMAIL PROTECTED]:&(\:~)[:;[:<"1&.>ps4) 20
1
ps4 seems faster than the Haskell solution, which was about 7
times as fast.
R.E. Boss
-----Oorspronkelijk bericht-----
Van: [EMAIL PROTECTED] [mailto:programming-
[EMAIL PROTECTED] Namens Roger Hui
Verzonden: dinsdag 14 augustus 2007 18:50
Aan: Programming forum
Onderwerp: Re: RE: [Jprogramming] Power sets
It is interesting to compare different representations
of the power set but not overly informative to compare
the time/space needed to compute them. Moreover,
it can be argued that #:i.2^n or even i.2^n represent
the power set pretty well, and:
ts '(i.@>: <@comb"0 ]) 15'
0.0135685 1.61126e6
ts 'i.2^15'
3.43619e_5 262912
At the very least, to make ps2 and the comb
approach comparable, you have to make the
latter work on arbitrary sets, such as 'abcd' or
i.3 2 2. For example,
ps3=: (i.@>:@# comb&.> #) {&.> <@]
----- Original Message -----
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--
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|\/| Randy A MacDonald | APL: If you can say it, it's done.. (ram)
|/\| ramacd <at> nbnet.nb.ca |
|\ | | The only real problem with APL is that
BSc(Math) UNBF'83 | it is "still ahead of its time."
Sapere Aude | - Morten Kromberg
Natural Born APL'er |
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