https://falgon.github.io/roki.log/posts/2018/%204/15/hermite-curve/ の図

plot0.py

# -*- coding:utf-8 -*-
#!/usr/bin/env python
import numpy as np
import matplotlib
matplotlib.use('Agg')

import matplotlib.pyplot as plt
import warnings
from matplotlib.font_manager import FontProperties

h, w = -2, 2
density = 1024

def non_parametric():
    warnings.simplefilter("ignore") # Python warns that it is `invalid value encountered in sqrt`, but that is the purpose itself.
    x = np.linspace(h, w, density)
    y = np.sqrt(x**3+x**2)
    return u'非パラメトリック', x, y

def parametric():
    x = []
    y = []
    for t in np.linspace(h, w, density):
        x.append(t**2-1)
        y.append(t**3-t)
    return u'パラメトリック', x, y

def setting(ax):
    ax.set_xlabel('x')
    ax.set_ylabel('y')
    ax.axvline(0, color = 'b', lw = 1.1)
    ax.axhline(0, color = 'b', lw = 1.1)
    ax.grid(color = 'gray')

if __name__ == '__main__':
    title, x, y = parametric()
    # Here, I use the font that is `IPA ゴシック (Ver.003.03)` to display Japanese(https://ipafont.ipa.go.jp/old/ipafont/download.html#en).
    fp = FontProperties(fname = 'ipag.ttf', size = 14) 
    fig, (axL, axR) = plt.subplots(ncols = 2, figsize = (10, 4), sharex = 'all', sharey = 'all')

    title0, x0, y0 = non_parametric()
    axL.plot(x0, y0)
    axL.set_title(title0, loc = 'center', fontproperties = fp)
    axL.set_xlim(h, w)
    axL.set_ylim(h, w)
    setting(axL)

    title1, x1, y1 = parametric()
    axR.plot(x1, y1)
    axR.set_title(title1, loc = 'center', fontproperties = fp)
    setting(axR)

    plt.savefig('curves0.png')