# -*- coding: utf-8 -*-
"""
演示二維插值。
"""
# -*- coding: utf-8 -*-
import numpy as np
from mpl_toolkits.mplot3d import Axes3D
import matplotlib as mpl
from scipy import interpolate
import matplotlib.cm as cm
import matplotlib.pyplot as plt
 
 
def func(x, y):
 return (x + y) * np.exp(-5.0 * (x ** 2 + y ** 2))
 
 
# X-Y軸分為20*20的網(wǎng)格
x = np.linspace(-1, 1, 20)
y = np.linspace(-1, 1, 20)
x, y = np.meshgrid(x, y) # 20*20的網(wǎng)格數(shù)據(jù)
 
fvals = func(x, y) # 計(jì)算每個(gè)網(wǎng)格點(diǎn)上的函數(shù)值 15*15的值
 
fig = plt.figure(figsize=(9, 6)) #設(shè)置圖的大小
# Draw sub-graph1
ax = plt.subplot(1, 2, 1, projection='3d') #設(shè)置圖的位置
surf = ax.plot_surface(x, y, fvals, rstride=2, cstride=2, cmap=cm.coolwarm, linewidth=0.5, antialiased=True) #第四個(gè)第五個(gè)參數(shù)表示隔多少個(gè)取樣點(diǎn)畫(huà)一個(gè)小面，第六個(gè)表示畫(huà)圖類(lèi)型，第七個(gè)是畫(huà)圖的線寬，第八個(gè)表示抗鋸齒
ax.set_xlabel('x')
ax.set_ylabel('y')
ax.set_zlabel('f(x, y)') #標(biāo)簽
plt.colorbar(surf, shrink=0.5, aspect=5) # 標(biāo)注
 
# 二維插值
newfunc = interpolate.interp2d(x, y, fvals, kind='cubic') # newfunc為一個(gè)函數(shù)
 
# 計(jì)算100*100的網(wǎng)格上的插值
xnew = np.linspace(-1, 1, 100) # x
ynew = np.linspace(-1, 1, 100) # y
fnew = newfunc(xnew, ynew) # 僅僅是y值 100*100的值 np.shape(fnew) is 100*100
xnew, ynew = np.meshgrid(xnew, ynew)
ax2 = plt.subplot(1, 2, 2, projection='3d')
surf2 = ax2.plot_surface(xnew, ynew, fnew, rstride=2, cstride=2, cmap=cm.coolwarm, linewidth=0.5, antialiased=True)
ax2.set_xlabel('xnew')
ax2.set_ylabel('ynew')
ax2.set_zlabel('fnew(x, y)')
plt.colorbar(surf2, shrink=0.5, aspect=5) # 標(biāo)注
plt.show()