# -*- coding: utf-8 -*-
"""
Random Numbers Utilities
========================
Defines random numbers generator objects:
- :func:`colour.algebra.random_triplet_generator`
"""
from __future__ import division, unicode_literals
import numpy as np
from colour.constants import DEFAULT_INT_DTYPE
from colour.utilities import runtime_warning, tstack
__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013-2019 - Colour Developers'
__license__ = 'New BSD License - https://opensource.org/licenses/BSD-3-Clause'
__maintainer__ = 'Colour Developers'
__email__ = 'colour-science@googlegroups.com'
__status__ = 'Production'
__all__ = ['RANDOM_STATE', 'random_triplet_generator']
RANDOM_STATE = np.random.RandomState()
[docs]def random_triplet_generator(size,
limits=np.array([[0, 1], [0, 1], [0, 1]]),
random_state=RANDOM_STATE):
"""
Returns a generator yielding random triplets.
Parameters
----------
size : int
Generator size.
limits : array_like, (3, 2)
Random values limits on each triplet axis.
random_state : RandomState
Mersenne Twister pseudo-random number generator.
Returns
-------
generator
Random triplets generator.
Notes
-----
- The test is assuming that :func:`np.random.RandomState` definition
will return the same sequence no matter which *OS* or *Python* version
is used. There is however no formal promise about the *prng* sequence
reproducibility of either *Python* or *Numpy* implementations, see
:cite:`Laurent2012a`.
Examples
--------
>>> from pprint import pprint
>>> prng = np.random.RandomState(4)
>>> random_triplet_generator(10, random_state=prng)
... # doctest: +ELLIPSIS
array([[ 0.9670298..., 0.7793829..., 0.4361466...],
[ 0.5472322..., 0.1976850..., 0.9489773...],
[ 0.9726843..., 0.8629932..., 0.7863059...],
[ 0.7148159..., 0.9834006..., 0.8662893...],
[ 0.6977288..., 0.1638422..., 0.1731654...],
[ 0.2160895..., 0.5973339..., 0.0749485...],
[ 0.9762744..., 0.0089861..., 0.6007427...],
[ 0.0062302..., 0.3865712..., 0.1679721...],
[ 0.2529823..., 0.0441600..., 0.7333801...],
[ 0.4347915..., 0.9566529..., 0.4084438...]])
"""
integer_size = DEFAULT_INT_DTYPE(size)
if integer_size != size:
runtime_warning(
'"size" has been cast to integer: {0}'.format(integer_size))
return tstack([
random_state.uniform(*limits[0], size=integer_size),
random_state.uniform(*limits[1], size=integer_size),
random_state.uniform(*limits[2], size=integer_size),
])