Python編程使用matplotlib繪制動態圓錐曲線示例
作為讓高中生心臟驟停的四個字,對於高考之後的人來說可謂刻骨銘心,所以定義不再贅述,直接擼圖,其標準方程分別為
在Python中,繪制動圖需要用到matplotlib
中的animation
包,其調用方法以及接下來要用到的參數為
ani = animation.FuncAnimation(fig, func, frames, interval)
其中fig
為繪圖窗口,func
為繪圖函數,其返回值為圖像,frames
為迭代參數,如果為整型的話,其迭代參數則為range(frames)
。
橢圓
為瞭繪圖方便,橢圓的參數方程為
代碼為:
# 這三個包在後面的程序中不再復述 import numpy as np import matplotlib.pyplot as plt import matplotlib.animation as animation a,b,c = 5,3,4 fig = plt.figure(figsize=(12,9)) ax = fig.add_subplot(autoscale_on=False, xlim=(-a,a),ylim=(-b,b)) ax.grid() line, = ax.plot([],[],'o-',lw=2) trace, = ax.plot([],[],'-', lw=1) theta_text = ax.text(0.02,0.85,'',transform=ax.transAxes) textTemplate = '''theta = %.1f°\n lenL = %.1f, lenR = %.1f\n lenL+lenR = %.1f''' xs,ys = [], [] def animate(i): if(i==0): xs.clear() ys.clear() theta = i*0.04 x = a*np.cos(theta) y = b*np.sin(theta) xs.append(x) ys.append(y) line.set_data([-c,x,c], [0,y,0]) trace.set_data(xs,ys) lenL = np.sqrt((x+c)**2+y**2) lenR = np.sqrt((x-c)**2+y**2) theta_text.set_text(textTemplate % (180*theta/np.pi, lenL, lenR, lenL+lenR)) return line, trace, theta_text ani = animation.FuncAnimation(fig, animate, 157, interval=5, blit=True) ani.save("ellipse.gif") plt.show()
雙曲線
雙曲線的參數方程為
設 a = 4 , b = 3 , c = 5 則代碼如下
a,b,c = 4,3,5 fig = plt.figure(figsize=(12,9)) ax = fig.add_subplot(autoscale_on=False, xlim=(-c,16),ylim=(-12,12)) ax.grid() line, = ax.plot([],[],'o-',lw=2) trace, = ax.plot([],[],'-', lw=1) theta_text = ax.text(0.01,0.85,'', transform=ax.transAxes) textTemplate = '''t = %.1f\n lenL = %.1f, lenR = %.1f\n lenL-lenR = %.1f''' xs,ys = [],[] def animate(t): if(t==-3): xs.clear() ys.clear() x = a*np.cosh(t) y = b*np.sinh(t) xs.append(x) ys.append(y) line.set_data([-c,x,c], [0,y,0]) trace.set_data(xs,ys) lenL = np.sqrt((x+c)**2+y**2) lenR = np.sqrt((x-c)**2+y**2) theta_text.set_text(textTemplate % (t, lenL, lenL, lenL-lenR)) return line, trace, theta_text frames = np.arange(-3,3,0.05) ani = animation.FuncAnimation(fig, animate, frames, interval=5, blit=True) ani.save("hyperbola.gif") plt.show()
拋物線
import numpy as np import matplotlib.pyplot as plt import matplotlib.animation as animation a,b,c = 4,3,5 p = 1 fig = plt.figure(figsize=(12,9)) ax = fig.add_subplot(autoscale_on=False, xlim=(-0.6,4.5),ylim=(-3,3)) ax.grid() ax.plot([-p/2,-p/2],[-5,5],'-',lw=2) line, = ax.plot([],[],'o-',lw=2) trace, = ax.plot([],[],'-', lw=1) theta_text = ax.text(0.05,0.85,'', transform=ax.transAxes) textTemplate = '''y = %.1f\n lenL = %.1f, lenF = %.1f\n lenL-lenF = %.1f''' xs,ys = [],[] def animate(y): if(y==-3): xs.clear() ys.clear() x = y**2/p/2 xs.append(x) ys.append(y) line.set_data([-p,x,p/2], [y,y,0]) trace.set_data(xs,ys) lenL = x+p/2 lenF = np.sqrt((x-p/2)**2+y**2) theta_text.set_text(textTemplate % (y, lenL, lenF, lenL-lenF)) return line, trace, theta_text frames = np.arange(-3,3,0.1) ani = animation.FuncAnimation(fig, animate, frames, interval=5, blit=True) ani.save("parabola.gif") plt.show()
極坐標方程
圓錐曲線在極坐標系下有相同的表達式,即
在matplotlib
中,極坐標圖像需要通過projection='polar'
來標識,其代碼為
p = 2 fig = plt.figure(figsize=(12,9)) ax = fig.add_subplot(autoscale_on=False, projection='polar') ax.set_rlim(0,8) trace, = ax.plot([],[],'-', lw=1) theta_text = ax.text(0.05,0.95,'',transform=ax.transAxes) textTemplate = 'e = %.1f\n' theta = np.arange(-3.1,3.2,0.1) def animate(e): rho = p/(1-e*np.cos(theta)) trace.set_data(theta,rho) theta_text.set_text(textTemplate % e) return trace, theta_text frames = np.arange(-2,2,0.1) ani = animation.FuncAnimation(fig, animate, frames, interval=100, blit=True) ani.save("polar.gif") plt.show()
以上就是Python使用matplotlib繪制動態的圓錐曲線示例的詳細內容,更多關於matplotlib繪制動態圓錐曲線的資料請關註WalkonNet其它相關文章!
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