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Re: Optimizing fixed point iteration

  • To: mathgroup at smc.vnet.net
  • Subject: [mg83097] Re: [mg83070] Optimizing fixed point iteration
  • From: Murray Eisenberg <murray at math.umass.edu>
  • Date: Sat, 10 Nov 2007 03:46:22 -0500 (EST)
  • Organization: Mathematics & Statistics, Univ. of Mass./Amherst
  • References: <200711091017.FAA12104@smc.vnet.net>
  • Reply-to: murray at math.umass.edu

What value of depth are you trying to use??

Yaroslav Bulatov wrote:
> Can anyone see the trick to speed up the following code significantly?
> 
> depth;step=.02;
> Table[(c = 0;
>    NestWhile[-4 (# - a) (# - b) &, .51, (c++; Abs[#1 - #2] > .1) &, 2,
>      depth]; c), {a, -1., 0., step}, {b, 0., 1., step}] // ArrayPlot
> 
> This makes a plot of the number of iterations needed for the quadratic
> fixed point iterations to converge, as a function of quadratic
> parameters, however it's too slow to get sufficient granularity
> 
> 

-- 
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305


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