from __future__ import division
import numpy as np
import matplotlib.pyplot as plt
import math
from scipy.integrate import odeint
from scipy.fftpack import fft, ifft
def pend(y, t, a, b, ohm):
theta, omega, phi = y
dydt = [omega, -b*omega-np.sin(theta)-a*np.cos(phi), ohm]
return dydt
b = 1.0/2.0 #beta
ohm = 2.0/3.0 #capital Omega
period = 2.0*math.pi/ohm #driving period
t0 = 0.0 #initial time
t = np.linspace(t0,t0+period*10**3,10**3+1) #time for Poincare map
theta0 = 0.75
omega0 = 1.6
phi0 = 0.8
y0 = [theta0,omega0,phi0] #initial conditions
N = 100 #number of transient points to delete
a_array = np.linspace(0,1.15,50) #varying parameter of a values
for a in a_array:
sol = odeint(pend,y0,t,args=(a,b,ohm)) #numerical integration of differential equation
sol = sol[N:10**3-N] #removing transients
w = sol[:,1] #frequency
A = np.full(len(w),a) #array of a-values
plt.plot(A, w)
plt.draw()
我正在尝试构建一个分叉图。在我们使用的方程组中,a是控制参数,我们在x轴上绘制0到1.15之间的值,而对于a的特定值,绘制值数组(称为w)。我不太确定如何在这样的for循环中绘制事物。我听说子图是最好的方法,但我不熟悉实现,可以使用一些帮助。谢谢!
答案 0 :(得分:0)
Unindenting最后一个命令对我有用。
from __future__ import division
import numpy as np
import matplotlib.pyplot as plt
import math
from scipy.integrate import odeint
from scipy.fftpack import fft, ifft
def pend(y, t, a, b, ohm):
theta, omega, phi = y
dydt = [omega, -b*omega-np.sin(theta)-a*np.cos(phi), ohm]
return dydt
b = 1.0/2.0 #beta
ohm = 2.0/3.0 #capital Omega
period = 2.0*math.pi/ohm #driving period
t0 = 0.0 #initial time
t = np.linspace(t0,t0+period*10**3,10**3+1) #time for Poincare map
theta0 = 0.75
omega0 = 1.6
phi0 = 0.8
y0 = [theta0,omega0,phi0] #initial conditions
N = 100 #number of transient points to delete
a_array = np.linspace(0,1.15,50) #varying parameter of a values
for a in a_array:
sol = odeint(pend,y0,t,args=(a,b,ohm)) #numerical integration of differential equation
sol = sol[N:10**3-N] #removing transients
w = sol[:,1] #frequency
A = np.full(len(w),a) #array of a-values
plt.plot(A, w)
plt.show()