Using Python, is it possible to plot implicit equations in x and y?
E.g.,
x³ y² + 3 x y + 9 x + x⁴ y⁴ + x⁴ + 3 = 0
or, using a Python-like notation
x**3*y**2 + 3*x*y + 9*x + x**4*y**4 + 3 = 0
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1have you tried it?M-Wi– M-Wi2020-04-16 05:29:22 +00:00Commented Apr 16, 2020 at 5:29
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You probably want to look at Plotting a polynomial in pythondspencer– dspencer2020-04-16 05:29:25 +00:00Commented Apr 16, 2020 at 5:29
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1 Answer
You can plot an implicit function using the external library
SymPy, namely using
sympy.plot_implicit that in turn uses Matplotlib under the
hood:
from sympy import symbols, plot_implicit
x, y = symbols('x y')
plot_implicit(x**3*y**2+3*x*y+9*x+x**4*y**4+x**4+3, x, y)
Another option, less direct than the use of SymPy, is to stretch the usage of plt.contour in Matplotlib
In [1]: import matplotlib.pyplot as plt
...: import numpy as np
...:
...: %matplotlib
...:
...: X = np.linspace(-4, 4, 201)
...:
...: x, y = np.meshgrid(X, X)
In [2]: z = x**3*y**2+3*x*y+9*x+x**4*y**4+x**4+3
In [3]: plt.contour(x, y, z, (0,))
Out[3]: <matplotlib.contour.QuadContourSet at 0x7fb866c805d0>
(note that (0,) is a tuple containing all the values for which you want to draw an isoline)
2 Comments
Vaasuawesome7
Okay, I will definitely try this out, thank you so much!
gboffi
Two weeks later. Have you tried my solutions? Did it work for you?