d, 26 Feb 2014 08:31:45 -0700
>> From: dongu...@gmail.com
>> To: programm...@jsoftware.com
>> Subject: Re: [Jprogramming] Combinatorial Maths with J
>>
>> ((!3)*!(7-3))%~!7
>>
>> 35
>>
>> 3!7
>>
>> 35
>>
>>
Jon,
You need the dyadic version of !, though it does yCx rather than xCy:
3!7
35
The following idiom delivers your required number of Steiner subsets:
({.%~/@:!}. ) 2 3 7
7
... if you're happy to treat the triples in this way.
It's derived from this verb which delivers 2!3 and 2!7:
((!3)*!(7-3))%~!7
35
3!7
35
On Wed, Feb 26, 2014 at 8:25 AM, Jon Hough wrote:
> I have a question about doing combinations and permutations with J.
> There is an easy to use factorial function (or is that verb) : !
> !5120
> Is there a combination verb? Or do I make my own?
> ((!3)*!(7
Well that's embarrassing. I should have read the definition more carefully.
> Date: Wed, 26 Feb 2014 08:31:45 -0700
> From: dongu...@gmail.com
> To: programm...@jsoftware.com
> Subject: Re: [Jprogramming] Combinatorial Maths with J
>
>((!3)*!(7-3))%~!7
>
> 35
&
bject: [Jprogramming] Combinatorial Maths with J
From: Jon Hough
Date: Wed, 26 Feb 2014 15:25:31 +
To: "programm...@jsoftware.com"
I have a question about doing combinations and permutations with J.
There is an easy to use factorial function (or is that verb) : !
!
I have a question about doing combinations and permutations with J.
There is an easy to use factorial function (or is that verb) : !
!5120
Is there a combination verb? Or do I make my own?
((!3)*!(7-3))%~!7
Gives 7 choose 3. I think I butchered that. Is there a better way to do this,
without all t
