Re: "Alternating" function
- To: mathgroup at smc.vnet.net
- Subject: [mg63274] Re: [mg63260] "Alternating" function
- From: Sseziwa Mukasa <mukasa at jeol.com>
- Date: Thu, 22 Dec 2005 00:04:35 -0500 (EST)
- References: <200512210435.XAA14743@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
On Dec 20, 2005, at 11:35 PM, Renan wrote:
> Hello,
>
> I want to make a "nested function" like: x + f[x - f[x + f[x - f[x
> + f[x]]]]].
>
> I've tried using Nest but I don't find how to keep switching between
> Plus and Minus: I would need something that would return an "index" so
> I could keep track of when I need to "switch" the operation. (e.g. if
> the "index" is odd, the operation is "Plus", otherwise is "Minus")
>
> How can I make this? I looked in the help but didn't find any
> informations.
>
> Thanks.
One way is to use Fold instead of Nest
Fold[x+#2 f[#1]&,x,Table[(-1)^i,{i,0,n-1}]
where n in is the desired level of nesting.
Regards,
Ssezi
- References:
- "Alternating" function
- From: Renan <renan.birck@gmail.com>
- "Alternating" function