utils.py

"""The module which is consisted of the utility functions."""
from __future__ import annotations

from collections.abc import Callable
from pathlib import Path

import matplotlib.pyplot as plt


def plot(
    outputPath: Path,
    output_file_name: str,
    probes: int,
    order: int,
    name: str,
    function: Callable[[float], float],
    approximation: Callable[[float], float],
    a: float,
    b: float,
) -> None:
    """Function to plot orginal function and it's approximation.

    Args:
        outputPath (Path): Directory where function saves approximation.png.
        output_file_name (str): Name of output file without extension.
        probes (int): Number of probes used in [a, b] interval.
        order (int): Order of approximation method, used only for title.
        name (str): Name of approximation method, used only for title.
        function (Callable[[float], float]): Original function.
        approximation (Callable[[float], float]): Approximation function.
        a (float): Left end of approximation interval.
        b (float): Right end of approximation interval.
    """
    plt.clf()
    plt.title(name + " approximation of " + repr(order) + " order")
    xArray = [a + (b - a) * i / probes for i in range(1, probes)]
    yArray = [function(x) for x in xArray]
    plt.plot(xArray, yArray, ls="-", lw=0.5, color="g", ms=5)
    yArray = [approximation(x) for x in xArray]
    plt.plot(xArray, yArray, ls="-", lw=0.5, color="r", ms=5)
    plt.legend(
        ["Original function", name + " approximation"],
        bbox_to_anchor=(0.5, -0.1),
        loc="lower center",
        ncol=3,
    )
    plt.tight_layout(rect=[0, 0, 1, 1])
    plt.gcf().set_size_inches(12, 9)
    plt.savefig(outputPath / (output_file_name + ".png"), dpi=100)