A pendulum simulation using Euler integration

pend_eul.py

from scipy.integrate import *
from scipy import *
from matplotlib.pyplot import *
##A pendulum simulation
##v0.2
##Alexandros Kourkoulas Chondrorizos
    
th=pi/4#((rand()*2)-1)*pi #initial angle
om=0 #initial angular velocity
u=0 #torque
    
y0 = [om, th] #initial values
t = linspace(0, 40, 4000) #

def f(y, t):
    mu=0.1 #friction factor
    m=1 #mass
    g=9.81 #grav. acceleration
    l=1 #length
    
    return (y[1],
        ((-mu*y[1]) + (m*g*l*sin(y[0])) + u)/(m*(l**2)))

    
r = odeint(f, y0, t)

#print(r)
#plot(t,r)
subplot(211),plot(t,r[:,1]),xlabel('Angle'),ylabel('')
subplot(212),plot(t,r[:,0],'r'),xlabel('Angular velocity'),ylabel('')
show()