Here's a modification of Raul's idea:
f=: 13 :'(i.y){((,[:(,+:)[:>:{:)^:(<.-:y))x'
1 f 4
1 2 4 5
1 f 7
1 2 4 5 10 11 22
3 f 7
3 4 8 9 18 19 38
Linda
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Aai
Sent: Friday, March 01, 2013 4:26 AM
To: [email protected]
Subject: Re: [Jprogramming] alternating application of monads
Different approach by analyzing the sequence
+/\1,,1,.+/\2,3*2^i.4
1 2 4 5 10 11 22 23 46 47 94
On 28-02-13 23:21, Johann Hibschman wrote:
> Thanks, that's interesting. It seems a little cumbersome, but it
> certainly works.
>
> It seems to do a lot of appending, but since it's continually building
> up the series, it never duplicates work. It can only do odd-length
> output sequences, but the even sequences are only a }: away.
>
>
> On Thu, Feb 28, 2013 at 9:30 AM, Raul Miller <[email protected]>
wrote:
>
>> Here's one approach:
>>
>> (, (, +:)@>:@{:)^:3]1
>> 1 2 4 5 10 11 22
>>
>> --
>> Raul
>>
>> On Thu, Feb 28, 2013 at 10:26 AM, Johann Hibschman
>> <[email protected]>
>> wrote:
>>> How do you generate a series produced by alternate application of
>>> two monads?
>>>
>>> For example, if I alternate >: and +: starting from 1, I get:
>>>
>>> 1 2 4 5 10 11 22 ...
>>>
>>> I can generate every other item in the series via (+:@>:)^:(i.6) 1,
>>> and I get close with (([: >: ])`([: +: ]))/\6#1, but the ordering of
>>> the operations is wrong. Agenda seems like it's also getting close,
>>> but I
>> can't
>>> quite make it work.
>>>
>>> Naively, I'd hoped that (>:`+:)^:(i. 5) 1 would work, but it does not.
>>>
>>> Thanks,
>>> Johann
>>> --------------------------------------------------------------------
>>> -- For information about J forums see
>>> http://www.jsoftware.com/forums.htm
>> ---------------------------------------------------------------------
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>> http://www.jsoftware.com/forums.htm
>>
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--
Met vriendelijke groet,
@@i = Arie Groeneveld
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