Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2005
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2005

[Date Index] [Thread Index] [Author Index]

Search the Archive

FixedPoint stops "when elements no longer change"?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg62776] FixedPoint stops "when elements no longer change"?
  • From: "Steven T. Hatton" <hattons at globalsymmetry.com>
  • Date: Mon, 5 Dec 2005 03:37:26 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

This is the example in The Mathematica Book for FixedPointList:

FixedPointList[Cos, 1.0]

{1., 0.540302, 0.857553, 0.65429, 0.79348, 0.701369, 0.76396, 0.722102, \
0.750418, 0.731404, 0.744237, 0.735605, 0.741425, 0.737507, 0.740147, \
0.738369, 0.739567, 0.73876, 0.739304, 0.738938, 0.739184, 0.739018,
0.73913, \
0.739055, 0.739106, 0.739071, 0.739094, 0.739079, 0.739089, 0.739082, \
0.739087, 0.739084, 0.739086, 0.739085, 0.739086, 0.739085, 0.739085, \
0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, \
0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, \
0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, \
0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, \
0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, \
0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, \
0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, \
0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085, 0.739085}

A bit of poking around showed me that this is using SameQ for SameTest.

"SameQ requires exact correspondence between expressions, except that it
considers Real numbers equal if their difference is less than the
uncertainty of either of them."

I guess I'm not seeing all the decimal places used to generate to list
above.  How would I determine the precision used to determine two
successive values are unchanged?

I tried FixedPointList[N[Cos[#], 2] &, 1.0], but that changed neither the
display, nor the result. 
-- 
The Mathematica Wiki: http://www.mathematica-users.org/
Math for Comp Sci http://www.ifi.unizh.ch/math/bmwcs/master.html
Math for the WWW: http://www.w3.org/Math/


  • Prev by Date: Re: How to draw elliptical curve
  • Next by Date: inequations
  • Previous by thread: Re: FixedPoint stops "when elements no longer change"?
  • Next by thread: Re: FixedPoint stops "when elements no longer change"?