Question

I am looking for the equivalent of the below Matlab function in Mathematica:

“R = poissrnd(lambda) generates random numbers from the Poisson distribution with mean parameter lambda. lambda can be a vector, a matrix, or a multidimensional array. The size of R is the size of lambda.”

An example of the function output below.

b = 95.7165   95.7165   95.7165   95.7165   95.7165   98.9772   98.9772   98.9772   98.9772    0.3876

poissrnd(b)

ans =100   115     81    90   109   106   104    87   104     2

How could I do something similar in Mathematica 8 ?

Answer 1

The Poisson distribution is defined only for integers. So you’ll need to use RandomInteger with PoissonDistribution like so:

poissrnd[lambda_]:=RandomInteger[PoissonDistribution[lambda]]

Usage:

b = {95.7165, 95.7165, 95.7165, 95.7165, 95.7165, 98.9772, 98.9772, 
  98.9772, 98.9772, 0.3876};

poissrnd /@ b

Out[1] = {104, 97, 67, 84, 96, 123, 93, 96, 100, 0}