[Numpy-discussion] How do I seed the radom number generator?

Keith Goodman kwgoodman at gmail.com
Sat Jun 24 12:32:04 CDT 2006


On 6/22/06, Robert Kern <robert.kern at gmail.com> wrote:
> Keith Goodman wrote:
> > How do I seed rand and randn?
>
> If you can, please use the .rand() and .randn() methods on a RandomState object
> which you can initialize with whatever seed you like.
>
> In [1]: import numpy as np
> rs
> In [2]: rs = np.random.RandomState([12345678, 90123456, 78901234])
>
> In [3]: rs.rand(5)
> Out[3]: array([ 0.40355172,  0.27449337,  0.56989746,  0.34767024,  0.47185004])

Using the same seed sometimes gives different results:

from numpy import random
def rtest():
  rs = random.RandomState([11,21,699,1])
  a = rs.rand(100,1)
  b = rs.randn(100,1)
  return sum(a + b)

>> mytest.rtest()
array([ 41.11776129])

>> mytest.rtest()
array([ 40.16631018])

>> numpy.__version__
'0.9.7.2416'

I ran the test about 20 times before I got the 40.166 result.




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