madrisan/dynamic-systems-and-chaos

#!/usr/bin/python3

# Logistic Equation: Comparing Initial Conditions
# Copyright (C) 2016-2019 Davide Madrisan <davide.madrisan@gmail.com>
# SPDX-License-Identifier: Apache-2.0

import sys

from lelib import Logistic, LogisticDiff
from utils import argparser, die


def parse_args():
    """This function parses and return arguments passed in"""
    descr = "Plot of Logistic Equation Time Series"
    examples = """
      # time series with a stable fixed point
      %(prog)s -0 0.4 -r 3.2 -n 50
      %(prog)s -0 0.4 -1 0.45 -r 3.2 -n 50
      # chaotic results (randon output)
      %(prog)s --x0 0.2 --x1 0.2000001 -r 4.0 -n 50
      %(prog)s -0 0.2 -r 3.6 -n 5000 --dots-only
      %(prog)s -0 0.9 -r 4.5 -n 50 --map=cubic
      %(prog)s -0 0.4 -r 0.8 -n 50 --map=sine"""

    parser = argparser(descr, examples)

    # By default select the Logistic Equation

    parser.add_argument(
        "-0",
        "--x0",
        action="store",
        dest="x0",
        type=float,
        required=True,
        help="1st initial condition",
    )
    parser.add_argument(
        "-1",
        "--x1",
        action="store",
        dest="x1",
        type=float,
        help="2nd initial condition (optional)",
    )
    parser.add_argument(
        "-d",
        "--dots-only",
        action="store_true",
        dest="dotsonly",
        help="do not connect the dots with lines (default: %(default)s)",
    )
    parser.add_argument(
        "-r",
        "--rate",
        action="store",
        dest="r",
        type=float,
        required=True,
        help="growth rate parameter",
    )
    parser.add_argument(
        "-s",
        "--skip",
        action="store",
        dest="s",
        type=int,
        default=0,
        help="skip plotting the first 's' iterations",
    )
    parser.add_argument(
        "-n",
        "--steps",
        action="store",
        dest="n",
        type=int,
        required=True,
        help="number of iterations",
    )
    parser.add_argument(
        "-m",
        "--map",
        action="store",
        dest="map_name",
        default="logistic",
        choices=["logistic", "cubic", "sine"],
        help="select the desired map (logistic, cubic, or sine)",
    )

    return parser.parse_args()


def main():
    args = parse_args()

    lemap = (
        LogisticDiff(args.r, args.n, args.x0, args.x1, args.s, args.map_name)
        if args.x1
        else Logistic(args.r, args.n, args.x0, args.s, args.map_name)
    )

    lemap.plotdots = not args.dotsonly
    lemap.plot()


if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt:
        die(3, "Exiting on user request")

    sys.exit()