sample#
- Uniform.sample(shape=(), *, method=None, rng=None)[source]#
Random sample from the distribution.
- Parameters:
- shapetuple of ints, default: ()
The shape of the sample to draw. If the parameters of the distribution underlying the random variable are arrays of shape
param_shape
, the output array will be of shapeshape + param_shape
.- method{None, ‘formula’, ‘inverse_transform’}
The strategy used to produce the sample. By default (
None
), the infrastructure chooses between the following options, listed in order of precedence.'formula'
: an implementation specific to the distribution'inverse_transform'
: generate a uniformly distributed sample and return the inverse CDF at these arguments.
Not all method options are available for all distributions. If the selected method is not available, a NotImplementedError` will be raised.
- rng
numpy.random.Generator
or scipy.stats.QMCEngine, optional Pseudo- or quasi-random number generator state. When rng is None, a new
numpy.random.Generator
is created using entropy from the operating system. Types other thannumpy.random.Generator
and scipy.stats.QMCEngine are passed tonumpy.random.default_rng
to instantiate aGenerator
.If rng is an instance of scipy.stats.QMCEngine configured to use scrambling and shape is not empty, then each slice along the zeroth axis of the result is a “quasi-independent”, low-discrepancy sequence; that is, they are distinct sequences that can be treated as statistically independent for most practical purposes. Separate calls to
sample
produce new quasi-independent, low-discrepancy sequences.
References
[1]Sampling (statistics), Wikipedia, https://en.wikipedia.org/wiki/Sampling_(statistics)
Examples
Instantiate a distribution with the desired parameters:
>>> import numpy as np >>> from scipy import stats >>> X = stats.Uniform(a=0., b=1.)
Generate a pseudorandom sample:
>>> x = X.sample((1000, 1)) >>> octiles = (np.arange(8) + 1) / 8 >>> np.count_nonzero(x <= octiles, axis=0) array([ 148, 263, 387, 516, 636, 751, 865, 1000]) # may vary
>>> X = stats.Uniform(a=np.zeros((3, 1)), b=np.ones(2)) >>> X.a.shape, (3, 2) >>> x = X.sample(shape=(5, 4)) >>> x.shape (5, 4, 3, 2)