tware.com] On Behalf Of Linda Alvord
Sent: Wednesday, June 27, 2012 1:26 AM
To: 'Programming forum'
Subject: Re: [Jprogramming] permutation list
I seem to know a little more J than I did 10 years ago, so here is a little
cleaner way to get the combinations. It is still slow and won
-Original Message-
From: programming-boun...@jsoftware.com
[mailto:programming-boun...@jsoftware.com] On Behalf Of Henry Rich
Sent: Tuesday, June 26, 2012 9:17 PM
To: Programming forum
Subject: Re: [Jprogramming] permutation list
Take the time to ponder R. E. Boss's version (in the Wiki). It is
beaut
> Linda
> >
> >
> > -Original Message-
> > From: programming-boun...@jsoftware.com
> > [mailto:programming-boun...@jsoftware.com] On Behalf Of bob therriault
> > Sent: Tuesday, June 26, 2012 3:02 PM
> > To: Programming forum
> > Subjec
-boun...@jsoftware.com] On Behalf Of Henry Rich
Sent: Tuesday, June 26, 2012 9:17 PM
To: Programming forum
Subject: Re: [Jprogramming] permutation list
Take the time to ponder R. E. Boss's version (in the Wiki). It is
beautiful, and I have tried without success to make any improvement.
$ 12
cr) $ [: i. ]
> $4 comb 10
> 4 210
>
> It might take a little time to remember what I did.
>
> Linda
>
>
> -Original Message-
> From: programming-boun...@jsoftware.com
> [mailto:programming-boun...@jsoftware.com] On Behalf Of bob therriault
> Sent: T
-
From: programming-boun...@jsoftware.com
[mailto:programming-boun...@jsoftware.com] On Behalf Of Linda Alvord
Sent: Tuesday, June 26, 2012 8:54 PM
To: 'Programming forum'
Subject: Re: [Jprogramming] permutation list
I wrote a book called "Probability in APL" many years ago. Whe
2 PM
To: Programming forum
Subject: Re: [Jprogramming] permutation list
Raul,
I don't think that there is a 1-1 correspondence between combinations and
permutations, since each combination of items can have a number of different
permutations. In the example you give the number of items is the sa
do in J? I know I've encountered several
of them before, but it might be nice to try to write them all out.
-Original Message-
From: programming-boun...@jsoftware.com
[mailto:programming-boun...@jsoftware.com] On Behalf Of Devon McCormick
Sent: Tuesday, June 26, 2012 3:54 PM
To: Program
way to define it, but this is how perm should
> behave if it were used dyadically.
>
>
>
> -Original Message-
> From: programming-boun...@jsoftware.com
> [mailto:programming-boun...@jsoftware.com] On Behalf Of bob therriault
> Sent: Tuesday, June 26, 2012 3:02 PM
>
On Tue, Jun 26, 2012 at 3:37 PM, Tirrell, Jordan (Consultant)
wrote:
> I'm sure there is a better way to define it, but this is how perm should
> behave if it were used dyadically.
Yes, I should have been paying closer attention.
Thanks,
--
Raul
---
mming-boun...@jsoftware.com] On Behalf Of bob therriault
Sent: Tuesday, June 26, 2012 3:02 PM
To: Programming forum
Subject: Re: [Jprogramming] permutation list
Raul,
I don't think that there is a 1-1 correspondence between combinations and
permutations, since each combination of items can h
consequence of the intended monadic definition.
-Original Message-
From: programming-boun...@jsoftware.com
[mailto:programming-boun...@jsoftware.com] On Behalf Of Raul Miller
Sent: Tuesday, June 26, 2012 2:14 PM
To: Programming forum
Subject: Re: [Jprogramming] permutation list
They
Raul,
I don't think that there is a 1-1 correspondence between combinations and
permutations, since each combination of items can have a number of different
permutations. In the example you give the number of items is the same because
the difference in the two arguments is 1, but this would not
They are certainly different.
2 comb 3
0 1
0 2
1 2
2 perm 3
0 1 2
0 2 1
1 0 2
In general, for n of m permutations and n of m combinations, the
permutations are going to be longer (length m instead of length n).
But the number of distinct items will be the same.
--
Raul
On Tue, Jun 26, 2
I thought that in the usual mathematical definition, combinations and
permutations differ: for permutations, order matters; for
combinations, it does not. Under this definition, the combinations of
3 things is just " i. 3 " - assuming we don't allow replacement? If
we do allow replacement, the pe
Note that the number of combinations and the number of permutions are the same.
And, perm is just: ! A.&i. ]
It seems like there ought to be a way of putting the permutations in 1
to 1 correspondence with the combinations (to give us a concise
expression for combinations).
--
Raul
On Tue, Jun
yes combinations not permutations
thought there might be a way that didn't loop
thank you for the references
On Tue, Jun 26, 2012 at 12:30 PM, R.E. Boss wrote:
> 4 comb 10
>
>
> R.E. Boss
>
>
> > -Oorspronkelijk bericht-
> > Van: programming-boun...@jsoftware.com [mailto:
> programming-b
4 comb 10
R.E. Boss
> -Oorspronkelijk bericht-
> Van: programming-boun...@jsoftware.com
> [mailto:programming-boun...@jsoftware.com] Namens ed bierly
> Verzonden: dinsdag 26 juni 2012 18:15
> Aan: programming@jsoftware.com
> Onderwerp: [Jprogramming] permutation list
>
> what is the b
This works in j6
require'stats'
$ 4 perm 10
210 10
I think the require statement might have to change for j7.
--
Raul
On Tue, Jun 26, 2012 at 12:14 PM, ed bierly wrote:
> what is the best way to get this list of 210 vectors?
>
> 4!10
> ---
Go to
http://www.jsoftware.com/jwiki/Essays/Combinations
and use R. E. Boss's version, which appears just above the pretty
pictures. This gives combinations, not permutations, but there are 210
of them.
Henry Rich
On 6/26/2012 12:14 PM, ed bierly wrote:
> what is the best way to get this li
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