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import os import numpy as np import matplotlib.pyplot as plt from scipy import integrate os.chdir(r'D:\projects\wordpress\ex37') os.getcwd() def f(t, y, args): m1, k1, g1, m2, k2, g2 = args return [y[1], - k1/m1 * y[0] + k2/m1 * (y[2] - y[0]) - g1/m1 * y[1], y[3], - k2/m2 * (y[2] - y[0]) - g2/m2 * y[3] ] m1, k1, g1 = 1.0, 10.0, 0.5 m2, k2, g2 = 2.0, 40.0, 0.25 args = (m1, k1, g1, m2, k2, g2) y0 = [1.0, 0, 0.5, 0] t = np.linspace(0, 20, 1000) r = integrate.ode(f) r.set_integrator('lsoda'); r.set_initial_value(y0, t[0]); r.set_f_params(args); dt = t[1] - t[0] y = np.zeros((len(t), len(y0))) idx = 0 while r.successful() and r.t < t[-1]: y[idx, :] = r.y r.integrate(r.t + dt) idx = idx + 1 fig = plt.figure(figsize=(10, 4)) ax1 = plt.subplot2grid((2, 5), (0, 0), colspan=3) ax2 = plt.subplot2grid((2, 5), (1, 0), colspan=3) ax3 = plt.subplot2grid((2, 5), (0, 3), colspan=2, rowspan=2) ax1.plot(t, y[:, 0], 'r') ax1.set_ylabel('$x_1$', fontsize=18) ax1.set_yticks([-1, -.5, 0, .5, 1]) ax2.plot(t, y[:, 2], 'b') ax2.set_xlabel('$t$', fontsize=18) ax2.set_ylabel('$x_2$', fontsize=18) ax2.set_yticks([-1, -.5, 0, .5, 1]) ax3.plot(y[:, 0], y[:, 2], 'k') ax3.set_xlabel('$x_1$', fontsize=18) ax3.set_ylabel('$x_2$', fontsize=18) ax3.set_xticks([-1, -.5, 0, .5, 1]) ax3.set_yticks([-1, -.5, 0, .5, 1]) plt.savefig("example37.png", dpi=100) plt.show() plt.close() <img class=" wp-image-188 aligncenter" src="https://gantovnik.com/bio-tips/wp-content/uploads/2019/01/example37.png" alt="example37" width="609" height="244" /> |
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