Python曲线拟合详解

import numpy as np
from scipy.optimize import curve_fit
def gauss(x, a, b, c):
    return a*np.exp(-(x-b)**2/c**2)

x = np.arange(100)/10
y = gauss(x, 2, 5, 3) + np.random.rand(100)/10

# 非线性拟合 abc为参数；para为拟合评价
abc, para = curve_fit(gauss, x, y)
print(abc)
# [2.03042233 5.01182397 3.10994351]

import matplotlib.pyplot as plt
plt.scatter(x, y, marker='.')

Y = gauss(x, *abc)
plt.plot(x, Y, lw=1)
plt.show()

curve_fit(f, xdata, ydata, p0=None, sigma=None, absolute_sigma=False, check_finite=True, bounds=(-inf, inf), method=None, jac=None, *, full_output=False, **kwargs)

# 创建一个函数模型用来生成数据
def func1(x, a, b, c, d):
    r = a * np.exp(-((x[0] - b) ** 2 + (x[1] - d) ** 2) / (2 * c ** 2))
    return r.ravel()
 
# 生成原始数据
xx = np.indices([10, 10])
z = func1(xx, 10, 5, 2, 5) + np.random.nORMal(size=100)/100
abcd, para = curve_fit(func1, xx, z)
print(abcd)
# [10.00258587  5.00146314  1.99952885  5.00138184]

z = z.reshape(10, 10)
Z = func1(xx, *abcd).reshape(10,10)

ax = plt.subplot(projection='3D')
ax.scatter3D(xx[0], xx[1], z, color='red')
ax.plot_surface(xx[0], xx[1], Z, cmap='rainbow')
plt.show()