How to: Numerical Derivative in Python

Learn how to take a simple numerical derivative of data using a difference formula in Python.

Script and resources to download can be found at: https://www.hageslab.com/python.html

Here we use "Spyder" IDE as the Python Shell and the following libraries: numpy and matplotlib

Here is the script:

import numpy as np
import matplotlib.pyplot as plt

def func(x,A,B):
return A*x**2+B*x

xlist = np.linspace(0,10,100)
ylist = func(xlist,2,1.4)

plt.figure(1,dpi=120)
plt.plot(xlist,ylist,label="Function")

def D(xlist,ylist):
yprime = np.diff(ylist)/np.diff(xlist)
xprime=[]
for i in range(len(yprime)):
xtemp = (xlist[i+1]+xlist[i])/2
xprime = np.append(xprime,xtemp)
return xprime, yprime

xprime, yprime = D(xlist,ylist)
plt.plot(xprime,yprime,label="Derivative")

xprime2, yprime2 = D(xprime,yprime)
plt.plot(xprime2,yprime2,label="2nd Derivative")
plt.legend()

Видео How to: Numerical Derivative in Python канала HagesLab