Talk:L-system

message: The three images of Penrose tilings are all untagged, and they don't have authorship info (dating from before "the big conversion").  I guess when the next untagged-image jihad gets underway these images may well meet with infinite justice, so we need to start thinking about replacements for them ASAP.  It's a bummer, as they're really attractive images. -- Finlay McWalter |  Talk 15:17, 7 October 2005 (UTC)
replies: text: These images were made by me with Winfract version 18.21, and we can tag them as public domain. I'll do that right the way. --xJaM 14:02, 21 October 2005 (UTC)
thread_title: Need new Penrose time images

message: Another nice example is a dragon curve. It is described by the following L-system:
:     variables :   L R 
:     constants :   + −
:     start     :   R   
:     rules     :   (R → R+L), (L → R−L)
meaning, respectively:
: L, R — step forward
: plus — turn right by 90°
: minus — turn left by 90°
Some initial strigns are:
:     n=0 : R 
:     n=1 : R+L
:     n=2 : R+L+R−L
:     n=3 : R+L+R−L+R+L−R−L
:     n=4 : R+L+R−L+R+L−R−L+R+L+R−L−R+L−R−L
CiaPan 20:53, 6 October 2006 (UTC)
thread_title:  Another example: Heighway dragon 

message: I've added graftal to the "See Also" section, but does it really need a separate article? There doesn't seem to be a whole lot of difference between L-systems and graftals. Perhaps the articles should be merged together. What do you think? -- Sakurambo 桜ん坊 13:53, 15 May 2007 (UTC)
thread_title:  Merge with [[graftal]] article? 

message: Some of the examples given in this article are a bit rubbish. The first example provides no explanation of what is going on. What does the string "ABAABABAABAABABAABABAABAABABAABAAB" have to do with algae? If the only important information is the length of each sequence, then how does this differ from Fibonacci's modelling of rabbit populations? The second example is completely redundant — the first example also generates a Fibonacci sequence, in case you hadn't noticed, and in any case, there's a much simpler algorithm for calculating this series, so in what way is this a useful example of the capabilities of an L-system? Examples 5 and 9 are quite useless without the rules used to produce these figures. -- Sakurambo 桜ん坊 14:10, 15 May 2007 (UTC)
replies: text: The Penrose tiling algorithm is given at the article of the same name, though the syntax is different. I could try translating between notations myself, but I am loathe to introduce errors. The modified Koch curve I'm not sure about, from the Koch curve page the standard curve uses
    Alphabet : F
    Constants : +, −
    Axiom : F++F++F
    Production rules:
    F → F−F++F−F 
I am guessing that the variant would alternate the production rule between F → F−F++F−F and F → F+F--F+F though this is pure speculation from the description, I have no idea how it was actually generated. As to the criticism of the first examples, algae was merely what he was historically trying to model the growth of, I don't think it is meant to represent the useful capabilities of the system, more to provide an example that correlates it with a well known algorithm. Nazlfrag (talk) 06:27, 13 June 2008 (UTC)
thread_title:  Better examples 

message: I added an explanation ASCII art to the first example and hope this doesn't get deleted immediately without discussion.
Visitors/readers of an encyclopedia ain't expected to be mathematicians, programmers or specialists in any way, are they? Readers should at least be able to understand the concept/essentials ... may be, one or the other reader then gets inspired to read on, learn and understand? And, may be, contribute? - Deerwood (talk) 03:38, 3 July 2008 (UTC)
thread_title:  Explanations 

message: Is there a reference for the statement that "L-systems can also be used to generate self-similar fractals such as iterated function systems"?  Richard Pinch (talk) 21:17, 16 July 2008 (UTC)
thread_title:  IFS 

message: Example 1 and 2 are practically the same system; having both is somewhat redundant.
Example 3(?) the dust example, should be changed to use conventional notation namely F for draw forward and f for move forward.
Example 5(?) the penrose tilings example, doesn't supply the rules for the system; the rules need to be added or the example scrapped.
All the examples really need reworking; the term 'constants' isn't one that's really used in any of the published papers on L-systems.  
The article could use an example of the various common types of L-system, stochastic (random), parametric and context sensitive.
87.194.144.173 (talk) 15:36, 3 May 2010 (UTC)
thread_title:  Examples... 

message: The rules give:
n = 1 : ABA
n = 2 : ABABBBABA
n = 3 : ABABBBABABBBBBBBBBABABBBABA
n = 4 : ABABBBABABBBBBBBBBABABBBABABBBBBBBBBBBBBBBBBBBBBBBBBBBABABBBABABBBBBBBBBABABBBABA
now only if each line is scaled to the same lenghth might you get something like the picture. --Paddy (talk) 23:33, 14 May 2011 (UTC)
replies: text: The scaling is so typical, perhaps it was overseen to mention it. The L-system itself is just the evolution of the character strings from one generation to the next. On top of that one may feed the character string of each generation as command sequence into a drawing machine like the (LOGO) Turtle. To obtain convergence of some kind one has to care how the characters relate to commands. This means adjusting the angles and step sizes, and also the orientation of the turtle at the start point, if in 2D. In the Cantor example this is simple -- three times as many characters, each a move forward, means one third of the step size from one generation to the next.--LutzL (talk) 13:19, 15 May 2011 (UTC)
thread_title: Cantor example is nothing like the diagram

message: Without wanting to make any statement about the facts, could the sentences "yes: in language theory, Chomsky is ultra-conservative" please be reworked or removed? This does not sound very encyclopedia-like. In general, the whole paragraph "Chomsky's conservative...refer to Chomsky.[2]" should probably not in the introduction of the article but maybe at some later point.
95.117.217.100 (talk) 11:24, 25 July 2011 (UTC)
replies: text: I have removed that paragraph from the article's lead. I am not completely sure what the editor who wrote this was trying to say, but in any case it has no relevance to the subject of this article. Gandalf61 (talk) 11:40, 25 July 2011 (UTC)
thread_title:  Chomskys "Ultra-conservative" views 

message: I don't know L-systems so well but in general formal languages the context-free ones are a strictly larger class that the mentioned equivalents of regular languages. It seems to apply here as well. Can someone competent look at it and eventually fix it? Neználek (talk) 13:17, 11 April 2012 (UTC)
replies: text: See the "subset or superset" talk topic below. 67.198.37.16 (talk) 20:53, 11 February 2024 (UTC)
thread_title:  Context-free systems 

message: As it is now, I can't tell if it's supposed to be about some type of mathematics or what. The article has tons of images of random plants and is talking all about biology and other non-math things. I'm pretty sure the concept of "L-System" is purely mathematical.... please remove these ancillary or tangential "connections" or at least dont make them the focus of the article anymore.  — Preceding unsigned comment added by 71.201.95.139 (talk) 21:02, 8 May 2013 (UTC)
replies: text: L-systems are a mathematical concept that have applications in modelling plants and other organisms. We can't write about L-systems without including these applications. However, I have modified the lead paragraph so that it says what an L-system is before it mentions applications in biology. Gandalf61 (talk) 08:48, 9 May 2013 (UTC)

text: The thing the article is talking about is what is known as Cyanobacteria. One of the common names for cyanobacteria is "blue-green algae". It may be a misnomer, but it is not at odds with common usage.  — Preceding unsigned comment added by 2003:69:CD6A:F401:D189:4DF8:E1B0:B7D0 (talk) 11:53, 15 September 2015 (UTC)
replies: text: It isn't at odds with common use of blue-green algae, but the term algae does not include blue-green algae. Referring to the one as the general case, and the other as a specific case, is plainly wrong. The Real Marauder (talk) 21:18, 18 May 2017 (UTC)
thread_title:  This Article Needs A ReWrite 

message: Should be 60 degrees not 90 degrees.
Flaviusvulso (talk) 19:25, 24 March 2017 (UTC)
thread_title:  Angle Used for Koch curve 

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thread_title:  External links modified