问题描述
在我的代码中,我从时间、位置测量中提取速度和加速度,并且在执行数值微分时收到索引错误:
VeLocityVsTime = np.empty((2,0),float)
for i in range(1,len(PosVsTime[0])-1):
veLocity = (PosVsTime[1][i+1] - PosVsTime[1][i-1]) / (PosVsTime[0][i+1] - PosVsTime[0][i-1])
VeLocityVsTime = np.append(VeLocityVsTime,[[PosVsTime[0][i]],[veLocity]],axis = 1)
#print(VeLocityVsTime)
accelerationvsTime = np.empty((2,float)
for j in range(1,len(VeLocityVsTime[1])-1):
acceleration = (VeLocityVsTime[1][i+1] - VeLocityVsTime[1][i-1]) / (VeLocityVsTime[0][i+1] - VeLocityVsTime[0][i-1])
accelerationvsTime = np.append(accelerationvsTime,[VeLocityVsTime[0][i]],[acceleration],axis=1)
print(accelerationvsTime)
错误是:
IndexError: index 50 is out of bounds for axis 0 with size 49
有关如何纠正此问题的任何提示?谢谢
解决方法
这里是完整的代码:错误发生在我声明加速度变量的第 42 行
import numpy as np
import matplotlib.pyplot as plt
PosVsTime = np.loadtxt("balldata.txt",delimiter=",").transpose()
#print(PosVsTime[0][0])
#t_0 = PosVsTime[0][0]
#pos_0 = PosVsTime[1][0]
#print("The initial state of this system at time = 0 is ",pos_0)
VelocityVsTime = np.empty((2,0),float)
for i in range(1,len(PosVsTime[0])-1):
velocity = (PosVsTime[1][i+1] - PosVsTime[1][i-1]) / (PosVsTime[0][i+1] - PosVsTime[0][i-1])
VelocityVsTime = np.append(VelocityVsTime,[[PosVsTime[0][i]],[velocity]],axis = 1)
#print(VelocityVsTime)
#plt.errorbar(VelocityVsTime[0],VelocityVsTime[1],fmt = '--k')
AccelerationvsTime = np.empty((2,float)
for j in range(1,len(VelocityVsTime[0])-1):
#acceleration = (VelocityVsTime[1][i+1] - VelocityVsTime[1][i-1]) / (VelocityVsTime[0][i+1] - VelocityVsTime[0][i-1])
#AccelerationvsTime = np.append(AccelerationvsTime,[VelocityVsTime[0][i]],[acceleration],axis=1)
print(AccelerationvsTime)