#!/usr/bin/env?python3
from?mpl_toolkits.mplot3d?import?Axes3D
from?matplotlib?import?cm
from?matplotlib.ticker?import?LinearLocator?FormatStrFormatter
import?matplotlib.pyplot?as?plt
import?numpy?as?np
?
?
def?heart_3d（xyz）:
?return?（x**2+（9/4）*y**2+z**2-1）**3-x**2*z**3-（9/80）*y**2*z**3
?
?
def?plot_implicit（fn?bbox=（-1.5?1.5））:
?‘‘‘?create?a?plot?of?an?implicit?function
?fn?...implicit?function?（plot?where?fn==0）
?bbox?..the?xyand?z?limits?of?plotted?interval‘‘‘
?xmin?xmax?ymin?ymax?zmin?zmax?=?bbox*3
?fig?=?plt.figure（）
?ax?=?fig.add_subplot（111?projection=‘3d‘）
?A?=?np.linspace（xmin?xmax?100）?#?resolution?of?the?contour
?B?=?np.linspace（xmin?xmax?40）?#?number?of?slices
?A1?A2?=?np.meshgrid（A?A）?#?grid?on?which?the?contour?is?plotted
?
?for?z?in?B:?#?plot?contours?in?the?XY?