Wikipedia

File:Logistic Map Bifurcation Diagram, Matplotlib.svg

Original file (SVG file, nominally 576 × 432 pixels, file size: 771 KB)

Summary

Description
English: A bifurcation diagram for the Logistic map:
The horizontal axis is the r parameter, the vertical axis is the x variable. A starting value of x=0.25 was used, and the map was iterated 1000 times in order to stabilize the values of x. 1,000,000 x -values were then calculated for each value of r and for each x value, the corresponding (x,r) pixel in the image was incremented by one. All values in a column (corresponding to a particular value of r) were then multiplied by the number of non-zero pixels in that column, in order to even out the intensities. See File:Logistic Map Bifurcation Diagram, Matplotlib, zoomed.png for a vectorized and therefore much faster version of this Python script.
Date
Source Own work
Author Morn
SVG development
InfoField
 
The SVG code is valid.
 
This plot was created with Matplotlib.
Source code
InfoField

Python code

Source code 
from pylab import *
from numpy import NaN
from matplotlib.colors import LogNorm

dr, dx = .001, .001
max_it = 1000000

R = arange(2.4, 4, dr)
X = arange(0, 1, dx)
Z = zeros((len(X), len(R)))

for ir, r in enumerate(R):
	print (ir, "of", len(R))
	z = .25
	for i in range(1000):
		z = r * z * (1 - z)
	for i in range(max_it):
		z = r * z * (1 - z)
		Z[-int(z / dx), ir]  = 1
	Z[:, ir] *= count_nonzero(Z[:, ir])

Z = where(Z > 0, Z, NaN)
save("logmap", Z)	# save array to file

# pick color bar range:
zmi = .005 * nanmax(Z)
zma = .1   * nanmax(Z)

imshow(Z, cmap = plt.cm.viridis_r, vmin = zmi, vmax = zma,
  interpolation = 'none', norm = LogNorm(),
  extent = (R.min(), R.max(), X.min(), X.max()))
xlabel("r")
ylabel("x")
savefig("Logistic Map Bifurcation Diagram, Matplotlib.svg")
show()

Licensing

I, the copyright holder of this work, hereby publish it under the following license:
w:en:Creative Commons
attribution share alike
This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
  • share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.
Annotations
InfoField
This image is annotated: View the annotations at Commons

Captions

Add a one-line explanation of what this file represents

Items portrayed in this file

depicts

inception

19 January 2019

File history

Click on a date/time to view the file as it appeared at that time.

Date/TimeThumbnailDimensionsUserComment
current13:55, 19 January 2019Thumbnail for version as of 13:55, 19 January 2019576 × 432 (771 KB)Mornuse a million samples (less noise)
12:45, 19 January 2019Thumbnail for version as of 12:45, 19 January 2019576 × 432 (979 KB)MornUser created page with UploadWizard

The following 4 pages use this file:

Global file usage

The following other wikis use this file:

Metadata

This file contains additional information, probably added from the digital camera or scanner used to create or digitize it.

If the file has been modified from its original state, some details may not fully reflect the modified file.

Retrieved from "https://en.wikipedia.org/wiki/File:Logistic_Map_Bifurcation_Diagram,_Matplotlib.svg"