Generate multiple independent random streams in python

Question

I want to generate multiple streams of random numbers in python. I am writing a program for simulating queues system and want one stream for the inter-arrival time and another stream for the service time and so on.

numpy.random() generates random numbers from a global stream.

In matlab there is something called RandStream which enables me to create multiple streams.

Is there any way to create something like RandStream in Python

Answer 1

For the sake of reproducibility you can pass a seed directly to random.Random() and then call variables from there. Each initiated instance would then run independently from the other. For example, if you run:

import random
rg1 = random.Random(1)
rg2 = random.Random(2)
rg3 = random.Random(1)
for i in range(5): print(rg1.random())
print('')
for i in range(5): print(rg2.random())
print('')
for i in range(5): print(rg3.random())

You'll get:

0.134364244112
0.847433736937
0.763774618977
0.255069025739
0.495435087092

0.956034271889
0.947827487059
0.0565513677268
0.0848719951589
0.835498878129

0.134364244112
0.847433736937
0.763774618977
0.255069025739
0.495435087092

Answer 2

Both Numpy and the internal random generators have instantiatable classes.

For just random:

import random
random_generator = random.Random()
random_generator.random()
#>>> 0.9493959884174072

And for Numpy:

import numpy
random_generator = numpy.random.RandomState()
random_generator.uniform(0, 1, 10)
#>>> array([ 0.98992857,  0.83503764,  0.00337241,  0.76597264,  0.61333436,
#>>>         0.0916262 ,  0.52129459,  0.44857548,  0.86692693,  0.21150068])