188 lines
7.2 KiB
Python
188 lines
7.2 KiB
Python
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import numpy as np
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import pytest
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import scipy.sparse as sp
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from scipy.special import comb
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from numpy.testing import assert_array_almost_equal
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from sklearn.utils.random import _random_choice_csc, sample_without_replacement
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from sklearn.utils._random import _our_rand_r_py
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###############################################################################
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# test custom sampling without replacement algorithm
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###############################################################################
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def test_invalid_sample_without_replacement_algorithm():
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with pytest.raises(ValueError):
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sample_without_replacement(5, 4, "unknown")
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def test_sample_without_replacement_algorithms():
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methods = ("auto", "tracking_selection", "reservoir_sampling", "pool")
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for m in methods:
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def sample_without_replacement_method(n_population, n_samples,
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random_state=None):
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return sample_without_replacement(n_population, n_samples,
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method=m,
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random_state=random_state)
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check_edge_case_of_sample_int(sample_without_replacement_method)
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check_sample_int(sample_without_replacement_method)
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check_sample_int_distribution(sample_without_replacement_method)
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def check_edge_case_of_sample_int(sample_without_replacement):
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# n_population < n_sample
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with pytest.raises(ValueError):
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sample_without_replacement(0, 1)
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with pytest.raises(ValueError):
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sample_without_replacement(1, 2)
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# n_population == n_samples
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assert sample_without_replacement(0, 0).shape == (0, )
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assert sample_without_replacement(1, 1).shape == (1, )
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# n_population >= n_samples
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assert sample_without_replacement(5, 0).shape == (0, )
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assert sample_without_replacement(5, 1).shape == (1, )
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# n_population < 0 or n_samples < 0
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with pytest.raises(ValueError):
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sample_without_replacement(-1, 5)
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with pytest.raises(ValueError):
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sample_without_replacement(5, -1)
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def check_sample_int(sample_without_replacement):
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# This test is heavily inspired from test_random.py of python-core.
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#
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# For the entire allowable range of 0 <= k <= N, validate that
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# the sample is of the correct length and contains only unique items
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n_population = 100
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for n_samples in range(n_population + 1):
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s = sample_without_replacement(n_population, n_samples)
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assert len(s) == n_samples
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unique = np.unique(s)
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assert np.size(unique) == n_samples
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assert np.all(unique < n_population)
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# test edge case n_population == n_samples == 0
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assert np.size(sample_without_replacement(0, 0)) == 0
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def check_sample_int_distribution(sample_without_replacement):
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# This test is heavily inspired from test_random.py of python-core.
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#
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# For the entire allowable range of 0 <= k <= N, validate that
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# sample generates all possible permutations
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n_population = 10
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# a large number of trials prevents false negatives without slowing normal
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# case
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n_trials = 10000
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for n_samples in range(n_population):
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# Counting the number of combinations is not as good as counting the
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# the number of permutations. However, it works with sampling algorithm
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# that does not provide a random permutation of the subset of integer.
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n_expected = comb(n_population, n_samples, exact=True)
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output = {}
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for i in range(n_trials):
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output[frozenset(sample_without_replacement(n_population,
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n_samples))] = None
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if len(output) == n_expected:
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break
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else:
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raise AssertionError(
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"number of combinations != number of expected (%s != %s)" %
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(len(output), n_expected))
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def test_random_choice_csc(n_samples=10000, random_state=24):
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# Explicit class probabilities
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classes = [np.array([0, 1]), np.array([0, 1, 2])]
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class_probabilities = [np.array([0.5, 0.5]), np.array([0.6, 0.1, 0.3])]
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got = _random_choice_csc(n_samples, classes, class_probabilities,
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random_state)
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assert sp.issparse(got)
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for k in range(len(classes)):
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p = np.bincount(got.getcol(k).toarray().ravel()) / float(n_samples)
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assert_array_almost_equal(class_probabilities[k], p, decimal=1)
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# Implicit class probabilities
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classes = [[0, 1], [1, 2]] # test for array-like support
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class_probabilities = [np.array([0.5, 0.5]), np.array([0, 1/2, 1/2])]
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got = _random_choice_csc(n_samples=n_samples,
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classes=classes,
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random_state=random_state)
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assert sp.issparse(got)
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for k in range(len(classes)):
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p = np.bincount(got.getcol(k).toarray().ravel()) / float(n_samples)
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assert_array_almost_equal(class_probabilities[k], p, decimal=1)
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# Edge case probabilities 1.0 and 0.0
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classes = [np.array([0, 1]), np.array([0, 1, 2])]
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class_probabilities = [np.array([1.0, 0.0]), np.array([0.0, 1.0, 0.0])]
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got = _random_choice_csc(n_samples, classes, class_probabilities,
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random_state)
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assert sp.issparse(got)
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for k in range(len(classes)):
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p = np.bincount(got.getcol(k).toarray().ravel(),
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minlength=len(class_probabilities[k])) / n_samples
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assert_array_almost_equal(class_probabilities[k], p, decimal=1)
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# One class target data
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classes = [[1], [0]] # test for array-like support
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class_probabilities = [np.array([0.0, 1.0]), np.array([1.0])]
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got = _random_choice_csc(n_samples=n_samples,
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classes=classes,
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random_state=random_state)
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assert sp.issparse(got)
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for k in range(len(classes)):
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p = np.bincount(got.getcol(k).toarray().ravel()) / n_samples
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assert_array_almost_equal(class_probabilities[k], p, decimal=1)
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def test_random_choice_csc_errors():
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# the length of an array in classes and class_probabilities is mismatched
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classes = [np.array([0, 1]), np.array([0, 1, 2, 3])]
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class_probabilities = [np.array([0.5, 0.5]), np.array([0.6, 0.1, 0.3])]
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with pytest.raises(ValueError):
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_random_choice_csc(4, classes, class_probabilities, 1)
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# the class dtype is not supported
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classes = [np.array(["a", "1"]), np.array(["z", "1", "2"])]
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class_probabilities = [np.array([0.5, 0.5]), np.array([0.6, 0.1, 0.3])]
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with pytest.raises(ValueError):
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_random_choice_csc(4, classes, class_probabilities, 1)
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# the class dtype is not supported
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classes = [np.array([4.2, 0.1]), np.array([0.1, 0.2, 9.4])]
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class_probabilities = [np.array([0.5, 0.5]), np.array([0.6, 0.1, 0.3])]
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with pytest.raises(ValueError):
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_random_choice_csc(4, classes, class_probabilities, 1)
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# Given probabilities don't sum to 1
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classes = [np.array([0, 1]), np.array([0, 1, 2])]
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class_probabilities = [np.array([0.5, 0.6]), np.array([0.6, 0.1, 0.3])]
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with pytest.raises(ValueError):
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_random_choice_csc(4, classes, class_probabilities, 1)
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def test_our_rand_r():
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assert 131541053 == _our_rand_r_py(1273642419)
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assert 270369 == _our_rand_r_py(0)
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