File:Logistic map approaching the scaling limit.webm

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Python code

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
import os

r_min, r_max = 3, 3.56994567
delta = 4.6692
frames_per_delta = 24
total_deltas = 6
frames = frames_per_delta * total_deltas
scaling_factor = delta**(1/frames_per_delta)
rs = r_max + (r_min - r_max) / (scaling_factor ** np.array(range(frames)))

for i, r in tqdm(enumerate(rs)):
    highest_exponent = 9
    fig, ax = plt.subplots(figsize=(30, 6))

    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(x_values, y_values, label=f'iteration = {2**n}', alpha=0.2, color='blue')

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

    fig.suptitle(f'Up to {2**(highest_exponent-1)} iterates of the Logistic map with r = {r}',y=1.0)
    plt.tight_layout()
    
    dir_path = "./logistic"
    if not os.path.exists(dir_path):
        os.makedirs(dir_path)

    fig.savefig(f"{dir_path}/{i}.png")
    plt.close()
export_to_video(["./logistic"], fps=12)
Date
Source Own work
Author Cosmia Nebula

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I, the copyright holder of this work, hereby publish it under the following license:
Creative Commons CC-Zero This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.
The person who associated a work with this deed has dedicated the work to the public domain by waiving all of their rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.

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6 April 2024

video/webm

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Date/TimeThumbnailDimensionsUserComment
current01:41, 7 April 2024Thumbnail for version as of 01:41, 7 April 2024 (619 KB)wikimediacommons>Cosmia NebulaUploaded own work with UploadWizard

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