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bundles / scipy 1.17.1 / scipy / sparse / _construct / random

function

scipy.sparse._construct:random

source: /scipy/sparse/_construct.py :1549

Signature

def   random ( m ,  n ,  density = 0.01 ,  format = coo ,  dtype = None ,  rng = None ,  data_rvs = None ,  * ,  random_state = None )

Summary

Generate a sparse matrix of the given shape and density with randomly distributed values.

Extended Summary

Parameters

m, n : int

shape of the matrix

density : real, optional

density of the generated matrix: density equal to one means a full matrix, density of 0 means a matrix with no non-zero items.

format : str, optional

sparse matrix format.

dtype : dtype, optional

type of the returned matrix values.

rng : {None, int, `numpy.random.Generator`}, optional

If rng is passed by keyword, types other than numpy.random.Generator are passed to numpy.random.default_rng to instantiate a Generator. If rng is already a Generator instance, then the provided instance is used. Specify rng for repeatable function behavior.

If this argument is passed by position or random_state is passed by keyword, legacy behavior for the argument random_state applies:

  • If random_state is None (or numpy.random), the numpy.random.RandomState singleton is used.

  • If random_state is an int, a new RandomState instance is used, seeded with random_state.

  • If random_state is already a Generator or RandomState instance then that instance is used.

This random state will be used for sampling the sparsity structure, but not necessarily for sampling the values of the structurally nonzero entries of the matrix.

data_rvs : callable, optional

Samples a requested number of random values. This function should take a single argument specifying the length of the ndarray that it will return. The structurally nonzero entries of the sparse random matrix will be taken from the array sampled by this function. By default, uniform [0, 1) random values will be sampled using the same random state as is used for sampling the sparsity structure.

Returns

res : sparse matrix

Examples

Passing a ``np.random.Generator`` instance for better performance: 
import scipy as sp
import numpy as np
rng = np.random.default_rng()
S = sp.sparse.random(3, 4, density=0.25, rng=rng)
✓
Providing a sampler for the values: 
rvs = sp.stats.poisson(25, loc=10).rvs
S = sp.sparse.random(3, 4, density=0.25, rng=rng, data_rvs=rvs)
✓
S.toarray()
✗
Building a custom distribution. This example builds a squared normal from np.random: 
def np_normal_squared(size=None, rng=rng):
    return rng.standard_normal(size) ** 2
S = sp.sparse.random(3, 4, density=0.25, rng=rng,
                     data_rvs=np_normal_squared)
✓
Or we can build it from sp.stats style rvs functions: 
def sp_stats_normal_squared(size=None, rng=rng):
    std_normal = sp.stats.distributions.norm_gen().rvs
    return std_normal(size=size, random_state=rng) ** 2
S = sp.sparse.random(3, 4, density=0.25, rng=rng,
                     data_rvs=sp_stats_normal_squared)
✓
Or we can subclass sp.stats rv_continuous or rv_discrete: 
class NormalSquared(sp.stats.rv_continuous):
    def _rvs(self,  size=None, random_state=rng):
        return rng.standard_normal(size) ** 2
X = NormalSquared()
Y = X()  # get a frozen version of the distribution
S = sp.sparse.random(3, 4, density=0.25, rng=rng, data_rvs=Y.rvs)
✓

See also

random_array

constructs sparse arrays instead of sparse matrices

Aliases

  • scipy.sparse.random

Referenced by

This package