pytutorial/numpy_random

Numpy -- Random numbers the non-legacy way

Goal

If you don't see something like np.random.default_rng() in your code then you are probably using the old [Legacy Random Generation] (https://numpy.org/doc/stable/reference/random/legacy.html#legacy-random-generation).

Don't use the legacy methods for new source code!!!

Do it like this:

import numpy as np

rng = np.random.default_rng()
random_values = rng.random(size=(2, 10))

Questions to David Rotermund

Random Generator

Typical usage

import numpy as np

rng = np.random.default_rng()
random_values = rng.random(size=(2, 10))

print(random_values)

Output:

[[0.81103943 0.1110591  0.42978062 0.47818377 0.91138636 0.47051031
  0.08662082 0.1643707  0.48717037 0.17870536]
 [0.94499902 0.74089677 0.12221184 0.61603001 0.91198789 0.33900609
  0.75832792 0.74465679 0.19940125 0.56674595]]

With seed:

import numpy as np

rng = np.random.default_rng(seed=23)
random_values = rng.random(size=(2, 10))

print(random_values)

Output:

[[0.69393308 0.64145822 0.12864422 0.11370805 0.65334552 0.85345711
  0.20177913 0.21801864 0.71658464 0.47069967]
 [0.41522193 0.3491478  0.06385375 0.45466617 0.30145328 0.38907675
  0.54029782 0.68358969 0.62475238 0.74270445]]

Changing the random number generator

Default

import numpy as np

rng = np.random.default_rng()
print(rng)  # -> Generator(PCG64)