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MathGroup Archive 2004

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Re: Re: NestList

  • To: mathgroup at smc.vnet.net
  • Subject: [mg50558] Re: Re: [mg50541] NestList
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Fri, 10 Sep 2004 04:05:58 -0400 (EDT)
  • Reply-to: hanlonr at cox.net
  • Sender: owner-wri-mathgroup at wolfram.com

This includes a timing:

Clear[myNest, myNestList];
myNest[f_, expr_, n_Integer] := 
    Last[myNestList[f, expr, n]];
myNestList[f_, expr_, n_Integer] := 
    Module[{m = 1, g, t0 = AbsoluteTime[]},
      g[x_] := Module[{},
          Print["Starting iteration #" <> ToString[m++] <>
              " at time " <> ToString[AbsoluteTime[] - t0]];
          f[x]];
      NestList[g, expr, n]];


Bob Hanlon

> 
> From: Bob Hanlon <hanlonr at cox.net>
To: mathgroup at smc.vnet.net
> Date: 2004/09/09 Thu AM 07:13:51 EDT
> To: Namrata Khemka <namrata.khemka at gmail.com>, 
<mathgroup at smc.vnet.net>
> Subject: [mg50558] Re: [mg50541] NestList
> 
> g[x_] := Module[{},
>       Print["Starting iteration #" <> ToString[n++]];
>       Pause[1]; (* simulates long calculation *)
>       f[x]];
> 
> n=1;soln=NestList[g, x, 3]
> 
> Starting iteration #1
> 
> Starting iteration #2
> 
> Starting iteration #3
> 
> {x, f[x], f[f[x]], f[f[f[x]]]}
> 
> 
> Bob Hanlon
> 
> > 
> > From: Namrata Khemka <namrata.khemka at gmail.com>
To: mathgroup at smc.vnet.net
> > Date: 2004/09/09 Thu AM 05:19:01 EDT
> > To: mathgroup at smc.vnet.net
> > Subject: [mg50558] [mg50541] NestList
> > 
> > Hello everyone,
> > 
> > I have a question regarding NestList function. 
> > 
> > I am applying a function on the expression n times.
> > 
> > NestList [function, expr, n]
> > 
> > However in my function I would like to know what is the current value
> > of n. In other words I would like to know what iteration it is on.
> > 
> > Is this possible?
> > 
> > Thanks in advance.
> > 
> > Namrata Khemka
> > 
> > 
> 


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