In [1]:
%matplotlib inline
from matplotlib import pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
from ipywidgets import interactive, IntSlider, FloatSlider, fixed
from IPython.display import display
from scipy import integrate
import numpy as np
This example is adapted from https://github.com/ipython/ipywidgets/blob/master/examples/notebooks/Lorenz%20Differential%20Equations.ipynb
In [2]:
def solve_lorenz(N=10, angle=0.0, max_time=4.0, sigma=10.0, beta=8./3, rho=28.0):
fig = plt.figure()
ax = fig.add_axes([0, 0, 1, 1], projection='3d')
ax.axis('off')
# prepare the axes limits
ax.set_xlim((-25, 25))
ax.set_ylim((-35, 35))
ax.set_zlim((5, 55))
def lorenz_deriv(x_y_z, t0, sigma=sigma, beta=beta, rho=rho):
"""Compute the time-derivative of a Lorenz system."""
x, y, z = x_y_z
return [sigma * (y - x), x * (rho - z) - y, x * y - beta * z]
# Choose random starting points, uniformly distributed from -15 to 15
np.random.seed(1)
x0 = -15 + 30 * np.random.random((N, 3))
# Solve for the trajectories
t = np.linspace(0, max_time, int(250*max_time))
x_t = np.asarray([integrate.odeint(lorenz_deriv, x0i, t)
for x0i in x0])
# choose a different color for each trajectory
colors = plt.cm.jet(np.linspace(0, 1, N))
for i in range(N):
x, y, z = x_t[i,:,:].T
lines = ax.plot(x, y, z, '-', c=colors[i])
plt.setp(lines, linewidth=2)
ax.view_init(30, angle)
plt.show()
return
In [3]:
w = interactive(solve_lorenz,
angle = FloatSlider(min=0, max=360, value=0),
N = IntSlider( min=0, max=50, value=10),
sigma = FloatSlider(min=0, max=50, value=10),
rho = FloatSlider(min=0, max=50, value=28),
beta = fixed(8./3))
display(w)