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方形左面.py
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方形左面.py
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# -*- coding: utf-8 -*-
"""
Created on Wed Nov 16 12:56:52 2016
@author: TanMingjun
"""
import matplotlib.pyplot as plt
import numpy as np
class billiard_rectangular:
def __init__(self,x_0,y_0,vx_0,vy_0,N,dt):
self.x_0 = x_0
self.y_0 = y_0
self.vx_0 = vx_0
self.vy_0 = vy_0
self.N = N
self.dt = dt
def motion_calculate(self):
self.x = []
self.y = []
self.vx = []
self.vy = []
self.t = [0]
self.x.append(self.x_0)
self.y.append(self.y_0)
self.vx.append(self.vx_0)
self.vy.append(self.vy_0)
for i in range(1,self.N):
self.x.append(self.x[i - 1] + self.vx[i - 1]*self.dt)
self.y.append(self.y[i - 1] + self.vy[i - 1]*self.dt)
self.vx.append(self.vx[i - 1])
self.vy.append(self.vy[i - 1])
if (self.x[i] < -1.0):
self.x[i],self.y[i] = self.correct('x>-1.0',self.x[i - 1], self.y[i - 1], self.vx[i - 1], self.vy[i - 1])
self.vx[i] = - self.vx[i]
elif(self.x[i] > 1.0):
self.x[i],self.y[i] = self.correct('x<1.0',self.x[i - 1], self.y[i - 1], self.vx[i - 1], self.vy[i - 1])
self.vx[i] = - self.vx[i]
elif(self.y[i] < -1.0):
self.x[i],self.y[i] = self.correct('y>-1.0',self.x[i - 1], self.y[i - 1], self.vx[i - 1], self.vy[i - 1])
self.vy[i] = -self.vy[i]
elif(self.y[i] > 1.0):
self.x[i],self.y[i] = self.correct('y<1.0',self.x[i - 1], self.y[i - 1], self.vx[i - 1], self.vy[i - 1])
self.vy[i] = -self.vy[i]
else:
pass
self.t.append(self.t[i - 1] + self.dt)
return self.x, self.y
def correct(self,condition,x,y,vx,vy):
vx_c = vx/100.0 #用来减小超出部分
vy_c = vy/100.0
while eval(condition):
x = x + vx_c*self.dt
y = y + vy_c*self.dt
return x-vx_c*self.dt,y-vy_c*self.dt
def reflect(self):
pass
def plot(self):
plt.figure(figsize = (8,8))
plt.xlim(-1,1)
plt.ylim(-1,1)
plt.xlabel('x')
plt.ylabel('y')
plt.plot(self.x,self.y,'g')
#plt.savefig('chapter3_3.31.png',dpi = 144)
plt.title('Trajectory of a billiard on a square table')
plt.show()
A=billiard_rectangular(0.2,0,1,0.31,12000,0.01)
A.motion_calculate()
A.plot()