Re: Optimizing fixed point iteration

*To*: mathgroup at smc.vnet.net*Subject*: [mg83101] Re: Optimizing fixed point iteration*From*: David Bailey <dave at Remove_Thisdbailey.co.uk>*Date*: Sun, 11 Nov 2007 02:55:08 -0500 (EST)*References*: <fh1ckb$csj$1@smc.vnet.net>

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 > > Are you perhaps under the misconception that your first line has set your 'depth' variable? David Bailey http://www.dbaileyconsultancy.co.uk