我正在尝试将指数定律拟合到我的数据中。我的
(x,y)
样本解释起来相当复杂,因此为了一般理解和可重复性,我会说:两个变量都是 float
和 continuous
、0<=x<=100
和 0<=y<=1
。
from scipy.optimize import curve_fit
import numpy
import matplotlib.pyplot as plt
#ydata=[...] is my list with y values, which contains 0 values
#xdata=[...] is my list with x values
transf_y=[]
for i in range(len(ydata)):
transf_y.append(ydata[i]+0.00001) #Adding something to avoid zero values
x=numpy.array(xdata,dtype=float)
y=numpy.array(transf_y,dtype=float)
def func(x, a, c, d):
return a * numpy.exp(-c*x)+d
popt, pcov = curve_fit(func, x, y,p0 = (1, 1e-6, 1))
print ("a = %s , c = %s, d = %s" % (popt[0], popt[1], popt[2]))
xx = numpy.linspace(300, 6000, 1000)
yy = func(xx, *popt)
plt.plot(x,y,label='Original Data')
plt.plot(xx, yy, label="Fitted Curve")
plt.legend(loc='upper left')
plt.show()
现在我的拟合曲线看起来一点也不像拟合指数曲线。相反,它看起来像一条移动平均曲线,就好像该曲线被添加为 Excel 中的趋势线一样。 可能是什么问题?如果有必要,我会找到一种方法来提供数据集,以使示例可重现。
除此之外,你的代码是正确的。
from scipy.optimize import curve_fit
import numpy
import matplotlib.pyplot as plt
xdata=[100.0, 0.0, 90.0, 20.0, 80.0] #is my list with y values, which contains 0 values - edit, you need some raw data which you fit, I inserted some
ydata=[0.001, 1.0, 0.02, 0.56, 0.03] #is my list with x values
transf_y=[]
for i in range(len(ydata)):
transf_y.append(ydata[i]+0.00001) #Adding something to avoid zero values
x1=numpy.array(xdata,dtype=float)
y1=numpy.array(transf_y,dtype=float)
def func(x, a, c, d):
return a * numpy.exp(-c*x)+d
popt, pcov = curve_fit(func, x1, y1,p0 = (1, 1e-6, 1))
print ("a = %s , c = %s, d = %s" % (popt[0], popt[1], popt[2]))
#ok, sorting your data
pairs = []
for i, j in zip(x1, y1):
pairs.append([i,j])
sortedList = sorted(pairs, key = lambda x:x[0])
sorted_x = numpy.array(sortedList)[:,0]
sorted_y = numpy.array(sortedList)[:,1]
#adjusting interval to the limits of your raw data
xx = numpy.linspace(0, 100.0, 1000)
yy = func(xx, *popt)
#and everything looks fine
plt.plot(sorted_x,sorted_y, 'o',label='Original Data')
plt.plot(xx,yy,label='Fitted Data')
plt.legend(loc='upper left')
plt.show()