CODEWITHSUNDEEP
pythonmatplotlibplotgraphing
Sanjay M
Sanjay M

Reputation: 31

Plot a poisson distribution graph in python

I would like to plot the Poisson function in Python using Matplotlib. The function is (exp(-5)*5^x)/factorial(x)

import numpy as np
import math
import matplotlib.pyplot as plt

t = np.arange(0, 20, 0.1)
d = []

for i in t:
    p = pow(5,i)
    q = p/math.factorial(i)
    d.append(q)

plt.plot( t, np.exp(-5)*d, 'bs')
plt.show()

But I get this error."Only size^1 arrays can be converted to Python scalars". How can I plot this graph? Thanks in advance

Upvotes: 3

Views: 23598

Answers (2)

bobrobbob
bobrobbob

Reputation: 1281

i think your function is not right: it's exp(-5)

import numpy as np
import matplotlib.pyplot as plt
from scipy.special import factorial

t = np.arange(0, 20, 0.1)
d = np.exp(-5)*np.power(5, t)/factorial(t)

plt.plot(t, d, 'bs')
plt.show()

poisson distribution

Upvotes: 3

jdowner
jdowner

Reputation: 736

The immediate problem is probably that you are using 't' instead of 'i' in your loop. However, you may want to avoid mixing python lists with numpy arrays. You could do it like,

import numpy as np
import scipy.misc
import math
import matplotlib.pyplot as plt

t = np.arange(0, 20, 0.1)
x = np.power(t, 5)
y = scipy.misc.factorial(t)

plt.plot( t, x / y, 'bs')
plt.show()

Upvotes: 0

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