Re: Re: Recursion on a list

• To: mathgroup at smc.vnet.net
• Subject: [mg28940] Re: [mg28908] Re: Recursion on a list
• From: Richard Palmer <mapsinc at bellatlantic.net>
• Date: Sat, 19 May 2001 22:27:57 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```I think a form like x = FoldList[Times,1,1+Rest[r]] would be still more
efficient and get the job done.  It avoids a lot of interpretive function
evaluations.

--
Richard Palmer
Framingham, MA 01701
508 877-3862

on 5/18/01 1:13 AM, Stephen P Luttrell at luttrell at signal.dra.hmg.gb wrote:

>
> "msc" <mscmsc at mediaone.net> wrote in message news:9e02kg\$305 at smc.vnet.net...
>> Greetings,
>>
>> I'm looking for an efficient method (i.e., with the use of an explicit
> loop)
>> for the following problem. I am working with large lists (several thousand
>> elements) of data. Denote one such list r. I would like to define a new
> list
>> x such that:
>>
>>
>> x[0] = 1.0
>>
>> x[t] = x[t-1]*(1.0 + r[t])
>>
>> Can anyone suggest an efficient way?
>
> This does what you want:
>
> FoldList[#1(1+#2)&,1,r]
>
> where r is the list of r-values, which would have been {r[1],r[2],r[3],..}
>
> --
> Stephen P Luttrell
> DERA, Malvern, U.K.
> luttrell at signal.dera.gov.uk
>
>
>

```

• Prev by Date: Hiding data in Cells?
• Next by Date: Re: TableForm Question
• Previous by thread: Re: Recursion on a list
• Next by thread: Speed up ListPlot3D