File:Logistic scaling with varying scaling factor.webm

Summary

Description
English: Desc

Matplotlib

import numpy as np
import matplotlib.pyplot as plt

def logistic_map(x, r):
    return r * x * (1 - x)

def function_iter(f, n, x, **kwargs):
    for _ in range(n):
        x = f(x, **kwargs)
    return x

import imageio.v3 as iio
import os
from natsort import natsorted
import moviepy.editor as mp

def export_to_video(dir_paths, fps=12):
    for dir_path in dir_paths:
        file_names = natsorted((fn for fn in os.listdir(dir_path) if fn.endswith('.png')))

        # Create a list of image files and set the frame rate
        images = []

        # Iterate over the file names and append the images to the list
        for file_name in file_names:
            file_path = os.path.join(dir_path, file_name)
            images.append(iio.imread(file_path))

        filename = dir_path[2:]
        iio.imwrite(f"{filename}.gif", images, duration=1000/fps, rewind=True)
        clip = mp.ImageSequenceClip(images, fps=fps)
        clip.write_videofile(f"{filename}.mp4")
    return

from tqdm import tqdm

r = 3.56994567
alpha_min, alpha_max = 2.4, 2.8
highest_exponent = 8
fig, ax = plt.subplots(figsize=(30, 10))

frames = 12 * 3
alphas = alpha_max + (alpha_min - alpha_max) * np.linspace(0, 1, frames)

for i, alpha in tqdm(enumerate(alphas)):
    fig, ax = plt.subplots(figsize=(30, 10))

    x_values = np.linspace(0, 1, 100000)
    y_values = x_values
    last_n_iter = 0

    for n in range(highest_exponent):
        n_iter = 2**n
        y_values = function_iter(logistic_map, n_iter - last_n_iter, y_values, r=r)
        last_n_iter = n_iter

        ax.plot(0.5+(x_values-0.5)*(-alpha)**(n), 0.5+(y_values-0.5)*(-alpha)**(n), label=f'iteration = {2**n}', 
                alpha=0.1, color='black', linewidth=4)

        ax.hlines(0.5, 0, 1, linewidth=0.3, alpha=0.8, linestyle='--', color='black')

        l_x = 5
        ax.set_xlim(0.5-l_x, 0.5+l_x)
        ax.set_ylim(-6, 4)

    fig.suptitle(f'Up to {2**(highest_exponent-1)} iterates of the Logistic map with r = {r}, each iterate scaled up by α = {alpha}',y=1.0)
    plt.tight_layout()

    dir_path = "./logistic_scaling"
    if not os.path.exists(dir_path):
        os.makedirs(dir_path)

    fig.savefig(f"{dir_path}/{i}.png")
    plt.close()
export_to_video(["./logistic_scaling"], fps=12)

Date
Source Own work
Author Cosmia Nebula

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.
Category:CC-BY-SA-4.0#Logistic%20scaling%20with%20varying%20scaling%20factor.webm
Category:Self-published work Category:Media needing categories as of 7 April 2024#Logistic%20scaling%20with%20varying%20scaling%20factor.webm Category:All media needing categories as of 2024#Logistic%20scaling%20with%20varying%20scaling%20factor.webm
Category:All media needing categories as of 2024 Category:CC-BY-SA-4.0 Category:Media needing categories as of 7 April 2024 Category:Pages with syntax highlighting errors Category:Self-published work