Talk:Julia set

message: The article uses the term "regular" in several places, with no link nor internal explanation.
Also, should "perturbation" really link to "Perturbation theory?" I think the term here is being used loosely, and Perturbation theory is about using slight changes to solve specific problems. Same word, but not a useful link.
Thomaso (talk) 15:31, 27 February 2016 (UTC)
thread_title:  Needs a definition of "regular" 

message: The preview of the GIF on the right cannot display. Could it be a problem with my browser?
Thanks, --Shiyu Ji (talk) 02:22, 16 April 2016 (UTC)
thread_title:  The GIF of Julia sets does not display well 

message: The Julia_circling.ogg video is very pretty but is 70MB. Is this really a suitable size to have on the wiki infrastructure? 79.75.125.119 (talk) 03:51, 8 January 2017 (UTC)
thread_title:  Huge video file 

message: Hello fellow Wikipedians,
I have just modified 2 external links on Julia set. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
*Added archive https://web.archive.org/web/20090109140601/http://local.wasp.uwa.edu.au/~pbourke/fractals/juliaset/ to http://local.wasp.uwa.edu.au/~pbourke/fractals/juliaset/
*Added archive https://web.archive.org/web/20120326020259/http://www.hightechdreams.com/weaver.php?topic=fractals to http://www.hightechdreams.com/weaver.php?topic=fractals
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
Cheers.—InternetArchiveBot (Report bug) 04:26, 29 April 2017 (UTC)
thread_title:  External links modified 

message: A Julia set is defined as boundary of the set of points such that \lim_{n\to\infty} z_n = f(z_{n-1}) \ne \infty. Notably, f(x) is a rational function, i.e. the result of the division of two polynomials P(x) and Q(x), where a polynomial “is an expression consisting of variables (or indeterminates) and coefficients, that involves only the operations of addition, subtraction, multiplication, and non-negative integer exponents” (qtd. from Polynomial).
Unfortunately, about half of the pictures in the Examples of Julia sets section aren’t actually Julia sets (such as e^z, e^{z^3}, \sqrt{\sinh z^2}), and none of them are non-polynomial rational functions.
# Is there a name for something like a Julia set where f(x) is a non-rational function? If so, we should move these images there.
# These images should be removed from the Julia set page — they’re confusing, incorrect, and unnecessary.
B637275 (talk) 20:58, 17 May 2017 (UTC)
thread_title: Example Julia set renders aren’t Julia sets

message: Currently, there are mistakes in the definition of the Fatou set in the section "Formal definition". First, number of Fatou domains can be infinite. Second, the Julia set of a rational map can coincide with the whole Riemann sphere, in which case there are no Fatou domains (and so their union is not dense in the plane). Also, the definition presented is not formal at all and leaves lots of space for interpretations. I think, this section should be rewritten carefully. I might do it later. Artem149598 (talk) 12:32, 2 August 2017 (UTC)
thread_title:  Mistakes in the definition of the Fatou set 

message: Hello fellow Wikipedians,
I have just modified 2 external links on Julia set. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
*Added archive https://web.archive.org/web/20060424085751/http://www.math.sunysb.edu/preprints.html to http://www.math.sunysb.edu/preprints.html
*Added archive https://web.archive.org/web/20110218135200/http://juliamap.googlelabs.com/ to http://juliamap.googlelabs.com/
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
Cheers.—InternetArchiveBot (Report bug) 11:15, 2 December 2017 (UTC)
thread_title:  External links modified 

message: The current pseudocode examples are wrong and do not produce graphical representations of Julia sets.
I hereby propose to improve the first example with the following changes:
# Before the loop set x = x0 and y = y0
# Explain the meaning of x and y (real and imaginary part)
# Set the loop to:
  while (x*x + y*y < 4  AND  iteration < max_iteration) 
  {
    xtemp = x*x - y*y
    y = 2*x*y + cy 
    x = xtemp + cx
    
    iteration = iteration + 1
  }
:Where cx and cy are the real and imaginary part of c.
In the second example I propose the following changes:
# Before the loop set x = x0 and y = y0 and do variable renaming analogous to above
# Set y = (x*x + y*y) ^ (n / 2) * sin(n * atan2(y, x)) + cy
# Set xtmp = (x*x + y*y) ^ (n / 2) * cos(n * atan2(y, x)) + cx
# Remove type specifier float
# Remove semicolons
=== Reasons ===
# Without renaming the variables in Example 1 the code would not work.
# Without changing c to cx, cy the code would not work.
# Variables with zero-index indicates start values and should not be changed.
# Type specifers must not occur inconsistently in pseudocode and in this case the type specifier is unnecessary.
# Semicolons should not occur inconsistently.
 Daknuett (talk) 18:36, 30 December 2017 (UTC)
thread_title:  Pseudocode examples 

message: # Without renaming the variables in Example 1 the code would not work.
# Without changing c to cx, cy the code would not work.
# Variables with zero-index indicates start values and should not be changed.
# Type specifers must not occur inconsistently in pseudocode and in this case the type specifier is unnecessary.
# Semicolons should not occur inconsistently.
 Daknuett (talk) 18:36, 30 December 2017 (UTC)
thread_title:  Reasons 

message: In section "Examples", the Julia set of f(z)=z^2 is described as unit circle, but evalutaing J(f_c) = \left\{z \in \mathbb C : \forall n \in \mathbb N, |f_c^n(z)| \le 2 \right\} as found under "Quadratic polynomials", we would obtain the closed unit disk.--Hagman (talk) 13:40, 25 July 2019 (UTC)
replies: text: The disk is the filled Julia set, not the Julia set. I fixed the error in "Quadratic polynomials". DaveWitteMorris (talk) 02:36, 2 October 2019 (UTC)
thread_title:  Contradictory definitions