I wrote the following code,
import numpy as np
from random import gauss
from random import seed
from pandas import Series
import matplotlib.pyplot as plt
import math
###variable declaration
R=0.000001 #radiaus of particle
beta=0.23 # shape factor
Ad=9.2#characteristic nanoscale defect area
gamma=4*10**-2 #surface tension
tau=.0001 #line tension
phi=-(math.pi/2)#spatial perturbation
lamda=((Ad)/(2*3.14*R)) #averge contcat line position
mu=0.001#viscosity of liquid
lamda_m=10**-9# characteristic size of adsorption site
KbT=(1.38**-24)*293 # boltzman constant with tempartaure
nu=0.001#moleculer volume in liquid phase 1
khi=3 #scaling factor
#deltaF=(beta*gamma*Ad)#surface energy perturbation
deltaF=19*KbT
# seed random number generator
seed(0)
# create white noise series
series = [gauss(0.0, 1.0) for i in range(1)]
series = Series(series)
#########################################
Z=0.0000001 #particle position
time=1
dt=1
for time in np.arange(1, 100, dt):
#####simulation loop#######
theta=np.arccos(-Z/R) #contact angle
theta_e=((math.pi*110)/180) #equilibrium contact angle
Z_e=-R*np.cos(theta_e)#equilibrium position of particle
C=3.14*gamma*(R-Z_e) #additive constant
Fsz= (gamma*math.pi*(Z-Z_e)**2)+(tau*2*math.pi*math.sqrt(R**2-Z**2))+C
Fz=Fsz+(0.5*deltaF*np.sin((2*math.pi/lamda)*(Z-Z_e)-phi))#surface force
#dFz=(((gamma*Ad)/2)*np.sin(2*math.pi/lamda))+((Z-Z_e)*(2*gamma*math.pi))-((tau*2*math.pi*Z)/(math.sqrt(R**2-Z**2)))
dFz=(deltaF*np.sin(2*math.pi/lamda))+((Z-Z_e)*(2*gamma*math.pi))-((tau*2*math.pi*Z)/(math.sqrt(R**2-Z**2)))
w_a=gamma*lamda_m**2*(1-np.cos(theta_e)) #work of adhesion
epsilon_z=2*math.pi*R*np.sin(theta)*mu*(nu/(lamda_m**3))*np.exp(w_a/KbT)#transitional drag
epsilon_s=khi*mu*((4*math.pi**2*R**2)/math.sqrt(Ad))*(1-(Z/R)**2)
epsilon=epsilon_z+epsilon_s
Ft=math.sqrt(2*KbT*epsilon)*series #thermal force
v=(dFz+Ft)/epsilon ##new velocity
Z=Z+v*dt #new position
print('z=',Z)
print('v=',v)
print('Fz=',Fz)
print('dFz',dFz)
print('time',time)
plt.plot(Z,time)
plt.show()
According to my code I suppose to have 99 values for everything (Fz, Z, v , time). While I print , I can see all the values but while I was trying to plot them with different parameters with respect to each other for analyzing, I never get any graph. Can anyone tell me, what is missing from my code with explanation?

Zandtimevalue of your for loop. Anyway, without really trying to dig into your math, I think you can do the entire thing withoutforloop usingnumpy. What is the variableseriesfor? I don't see it being used anywhere.