Collatz Graph

collatz.py

#!/usr/bin/python3
import matplotlib.pyplot as plt # matplotlib>=3.8.2
from math import floor

def collatz(x: int) -> list[int]:
    if x <= 0:
        raise ValueError("x must be a positive integer")
    output = []
    while x > 1:
        output.append(x)
        x = floor(x/2 if x % 2 == 0 else (3 * x) + 1)
    output.append(x)
    return output

def main() -> None:
    try:
        val = int(input("Please enter a number: ").strip())

        y = collatz(val)
        x = [n for n in range(len(y))]
        
        plt.plot(x, y)
        
        plt.xlabel("Generation")
        plt.ylabel("Value")
        plt.title(f"Collatz Conjecture from {val}")

        plt.show()
    except ValueError:
        return

if __name__ == "__main__":
    main()