|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 |
import os import numpy as np import matplotlib.pyplot as plt os.chdir(r'D:\\data\scripts\wordpress\ex54') os.getcwd() A,freq,tau=10,4,0.5 def f(t,A,freq,tau): return A*np.exp(-t/tau)*np.cos(2*np.pi*freq*t) tmax,dt=1,0.01 t=np.arange(0,tmax,dt) yexact=f(t,A,freq,tau) y=yexact + np.random.randn(len(yexact))*2 plt.plot(t,yexact) plt.scatter(t,y,marker='o',facecolors='blue', edgecolors='black') def residuals(p,y,t): A,freq,tau=p return y-f(t,A,freq,tau) from scipy.optimize import leastsq p0=5,5,1 plsq=leastsq(residuals,p0,args=(y,t)) plsq[0][1] pfit = (plsq[0][0],plsq[0][1],plsq[0][2]) plt.plot(t,y,'o',c='k',label='Data') plt.plot(t,yexact,c='green',label='Exact') plt.plot(t,f(t,plsq[0][0],plsq[0][1],plsq[0][2]),c='red',label='Fit') plt.legend() plt.tight_layout() plt.savefig("ex54.png", dpi=100) plt.show() plt.close() |
Recent Comments