Drawing Fractals with Hyperbolic Iterated Functions Sets (IFS) in Zn/Dn Symmetry Groups
Predefined Fractal Configurations
Free
Surprise
Divinity
Stars
Vortex
Entropy
Get Fractal
Symmetry Properties of Fractal Icons
Fool
Trinity
Cross
Morning
Lovers
Devil
Justice
Hermite
Wheel of Fortune
Manual Settings (Mathematicians)
Projections on
Z-pole off
Affine Parameters
Iterated Function Set
Plotter Settings
Colors
Axis off
Export off
Other Actions
IFS data
Back
Drawing
New
Redraw
Repaint
Add iterations
+10K
+100K
+1M
+10M
Close
Occurrences and Fractal Dimensions
G-Matrix: coefficients of the hyperbolic IFS
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Generation of Fractal Icons by Hyperbolic Iterated Function Set
Overview of this Fractal Generator
This free online software allows to generate fractal icons with diverse shapes, colors and symmetry
To generate a fractal, you simply push the red button Get Fractal
Predefined Fractal Configurations
You can select some pre-defined configurations of fractals - Free, Surprise, Divinity, Stars, Vortex, Entropy -
The Surprise configuration is set by default
The configuration Free resets the fractal to a simple Sierpinski triangle
You can manually set the shape of the fractal at any moment (see below)
Symmetry Properties (Zn Groups) of Fractals Icons
You can select the Zn symmetry group from 3 to 9
The default Fool means that the Zn is randomly chosen between 3 and 9
The Wheel of Fortune allows to set a random Zn of high rank, chosen between 30 and 60
You can manually set the Zn symmetry of the fractal at any moment (see below)
Manual Settings: → Projection, Z-Pole, Affine Parameters, Iterated Function Set
The Projection button allows to choose if linear projections - linear transformation with a determinant equal zero - are also randomly allowed or not - it is on by default
The Z-pole option allows to add a linear transformation with a zero fixed point to any set of transformations
The Affine Parameters and Iterated Function Set buttons open the windows where you can manually set the parameters of the function sets
Each linear transformation matrix is decomposed in the product of scale, rotation, stretch and shear matrix
The Scale parameter is an homogeneous scale scalar which will be multiplied by the identity matrix
The Stretch parameter allow to indicate a degree of non-homogeneous scale in the x and y direction: its value is rearranged in the function k=(1+s)/(1-s) and then in a unitary diagonal matrix with k and 1/k as eigenvalues
The Rotation angle defines a rotation matrix operating on the left of the scale matrix
The Shear angle defines a rotation matrix operating on the right of the scale matrix
With the symmetry slider, you can manually select the Zn symmetry of the set
With the nb-ifs slider you can manually set the total number of different function per each symmetry mode in the set - default is 3
Plotter Settings: → Colors, Axis, Export
The colors in the fractal icon image are proportional to the probability that a given point is visited during the iterations
Clicking the Colors button opens a window where you can select the color palette of the fractal icon
You can either select one of the three pre-defined color palettes at the bottom of the window, or define your own color palette
You define a color palette by choosing the hue, the saturation and the lightness of the two extreme colors of the palette
The program will then adjust the intermediate colors proportionally to the gradient between the two extreme colors you defined
By activating the axis option, you ask the program to plot also the coordinate axis of the space and the fixed points of each function in the iterated function set
The fractal icon images are plotted on a html canvas element: such element doesn't allow to copy and export the image
By clicking on the Export button, you convert the image into a png image: you can then right click on the image and save the image anywhere on your computer
Note that the image is exported without any background: you will need to add the background on any other application where you wish to display the exported image
Drawing: → New, Redraw, Repaint
The New button generates a new fractal icon with the same settings as the current one: the current one is erased
The Redraw button draw the icon again from the beginning
The Repaint button allows to apply new color settings to the existing fractal icon
Add Iterations: → +10k, +100k, +1M, +10M
The initial fractal icon is plot after 10,000 iterations of the function set: this should prevent users with low calculation capacities (eg. smartphones) to be locked in too long waiting times
The initial fractal image is usually of poor quality, but allows you to identify nice icons
You can then add iterations to get a high quality icon and to finetune the fractal image
Note that a fractal is defined as the result of an infinity of iterations, what is obviously impossible on a computer
Usually you get most of the image after 1M iterations, but sometimes the image yet improves significantly up to 100M iterations
Be ready to wait if you launch fractal iterations over 100k without a powerful enough computer
IFS data (Mathematicians)
For the mathematicians, we plot in the IFS data all the most significant parameters of the iterated function set
A first matrix show (i) the number of times a point has been hit by an iteration divided in percentiles, and including the minimum and maximum of such hits numbers, (ii) the total number of hits (pixels points) and of iterations realized, (iii) an estimate of the mathematical ball-dimension of the fractal and (iv) the maximum radius of the fractal
In the left G-matrix you find the scale, stretch, rotation, shear, radius and phase of the fixed points, if the mirror was on - if mr=0 you get a projection, if mr=-1 you get a reflection -, the determinant and the trace of the transformation
In the right G-Matrix, for the same transformation, you find the standard parameters of the linear matrix (G), the translation parameter t and the applied probability of appearance of a transformation at each iteration
Brief Mathematical Hints for Fractal Generation
An IFS is a set of affine transformations
Each of those affine transformation is a contraction - the absolute value of the scales in the x and y direction are less than unity - A set of affine contractions is called an Hyperbolic IFS
It is proven that any hyperbolic IFS has a unique set of fixed points, called the attractor A of the HIFS
Starting with a random complex number z (or a point in the plane) and applying iteratively a transformation randomly selected within the HIFS, after a transitory period (eg. 500 iterations) the application inevitably hits the attractor
Continuing to apply iteratively a transformation randomly selected within the HIFS, the program shows the attractor of the HIFS, coloring the pixel proportionally to the hits