# Util Module¶

poisson_approval.utils.Util.array_to_d_candidate_value(values)[source]

Convert an array to a dictionary of candidates and values

Parameters: values (ndarray) – An array of size 3. The corresponding dictionary. DictPrintingInOrderIgnoringZeros

Examples

>>> values = [42, 51, 69]
>>> array_to_d_candidate_value(values)
{'a': 42, 'b': 51, 'c': 69}

poisson_approval.utils.Util.candidates_to_d_candidate_probability(candidates)[source]

Convert a set of candidates to a dictionary of probabilities (random tie-break).

Parameters: candidates (set) – A subset of {'a', 'b', 'c'}. Typically: a set of winners. Key: 'a', 'b' or 'c'. Value: the probability of this candidate winning with a uniformly random tie-break. DictPrintingInOrderIgnoringZeros

Examples

>>> winners = {'a', 'b'}
>>> candidates_to_d_candidate_probability(winners)
{'a': Fraction(1, 2), 'b': Fraction(1, 2)}

poisson_approval.utils.Util.candidates_to_probabilities(candidates)[source]

Convert a set of candidates to an array of probabilities (random tie-break).

Parameters: candidates (set) – A subset of {'a', 'b', 'c'}. Typically: a set of winners. Array of size 3. For example, the first coefficient is the probability that candidate a win by a random tie-break. ndarray

Examples

>>> winners = {'a', 'b'}
>>> candidates_to_probabilities(winners)
array([Fraction(1, 2), Fraction(1, 2), 0], dtype=object)

poisson_approval.utils.Util.d_candidate_value_to_array(d_candidate_value)[source]

Convert a dictionary of candidates and values to an array

Parameters: d_candidate_value (dict) – Key: 'a', 'b' or 'c'. The corresponding array. ndarray

Examples

>>> d_candidate_value = {'a': 42, 'b': 51, 'c': 69}
>>> d_candidate_value_to_array(d_candidate_value)
array([42, 51, 69])

poisson_approval.utils.Util.give_figure(n, singular, plural=None)[source]

Combine a number with a unit, whose word can be singular or plural.

Parameters: n (int) – The number. singular (str) – The singular word. plural (str) – The plural word. Default: the singular with a final ‘s’. The number and the word. str

Examples

>>> give_figure(1, 'apple')
'1 apple'
>>> give_figure(2, 'apple')
'2 apples'
>>> give_figure(1, 'equilibrium', 'equilibria')
'1 equilibrium'
>>> give_figure(2, 'equilibrium', 'equilibria')
'2 equilibria'

poisson_approval.utils.Util.image_distribution(factory, n_samples, f, conditional_on=None)[source]

Distribution of f(something) for a random something.

Parameters: factory (callable or tuple) – This can be: Either a callable that takes no input and that outputs a (random) something, Or a tuple of such factories (cf. examples below). n_samples (int) – Number of samples. f (callable) – A function that take as input(s) the output(s) of the factory(ies). conditional_on (callable) – A function that take as input(s) the output(s) of the factory(ies) and that returns a Boolean. Default: always True. Keys: the obtained outputs for f. Values: the probability that f(something) has this output when something is generated by factory, conditional on the fact that it meets conditional_on, based on a Monte-Carlo estimation of n_samples trials. DictPrintingInOrder

Examples

In this basic example with one factory, we compute the distribution of n modulo 10, when n is drawn uniformly at random between 0 included and 100 excluded, conditionally on the fact that n is even:

>>> initialize_random_seeds()
>>> def rand_integer():
...     return np.random.randint(0, 100)
>>> def modulo_10(n):
...     return n % 10
>>> def is_even(n):
...     return n % 2 == 0
>>> image_distribution(factory=rand_integer, n_samples=100, f=modulo_10, conditional_on=is_even)
{0: 0.21, 2: 0.21, 4: 0.2, 6: 0.18, 8: 0.2}


In this example with a tuple of factories, we compute the distribution of a mod b, when a is drawn uniformly at random between 0 included and 100 excluded, and b is drawn uniformly at random between 1 included and 11 excluded:

>>> initialize_random_seeds()
>>> def rand_integer():
...     return np.random.randint(0, 100)
>>> def rand_divider():
...     return np.random.randint(1, 11)
>>> def modulo(a, b):
...     return a % b
>>> image_distribution(factory=(rand_integer, rand_divider),
...                    n_samples=100, f=modulo)
{0: 0.31, 1: 0.16, 2: 0.18, 3: 0.12, 4: 0.07, 5: 0.04, 6: 0.02, 7: 0.08, 9: 0.02}

poisson_approval.utils.Util.initialize_random_seeds(n=0)[source]

Initialize the random seeds.

Parameters: n (int) – The desired random seed. Default: 0.
poisson_approval.utils.Util.isnan(x)[source]

Is nan.

Parameters: x (Number) – True if x is nan. bool

Notes

This extends the usual numpy function isnan to fractions and sympy expressions.

Examples

>>> values = [sp.sqrt(3) - sp.sqrt(2), sp.nan,
...           sp.oo, - sp.oo,
...           sp.Rational(3, 5), Fraction(3, 5),
...           1, 0.42, np.inf, -np.inf, np.nan]
>>> print([x for x in values if isnan(x)])
[nan, nan]

poisson_approval.utils.Util.isneginf(x)[source]

Is negative infinity.

Parameters: x (Number) – True if x is negative infinity. bool

Notes

This extends the usual numpy function isneginf to fractions and sympy expressions.

Examples

>>> values = [sp.sqrt(3) - sp.sqrt(2), sp.nan,
...           sp.oo, - sp.oo,
...           sp.Rational(3, 5), Fraction(3, 5),
...           1, 0.42, np.inf, -np.inf, np.nan]
>>> print([x for x in values if isneginf(x)])
[-oo, -inf]

poisson_approval.utils.Util.isposinf(x)[source]

Is positive infinity.

Parameters: x (Number) – True if x is positive infinity. bool

Notes

This extends the usual numpy function isposinf to fractions and sympy expressions.

Examples

>>> values = [sp.sqrt(3) - sp.sqrt(2), sp.nan,
...           sp.oo, - sp.oo,
...           sp.Rational(3, 5), Fraction(3, 5),
...           1, 0.42, np.inf, -np.inf, np.nan]
>>> print([x for x in values if isposinf(x)])
[oo, inf]

poisson_approval.utils.Util.iterate_simplex_grid(d, denominator)[source]

Iterate over the points in the simplex, with rational coordinates of a given denominator

Parameters: d (int) – Number of coordinates. In other words, we consider the simplex of dimension d - 1. denominator (int or iterable) – The coordinates will be fractions with this denominator. If an iterable is given, we consider each denominator given by the iterable. Each tuple of length d, whose coordinates are fractions of the given denominator, and whose sum is 1. tuple

Examples

>>> for t in iterate_simplex_grid(d=3, denominator=range(1, 3)):
...     print(t)
(1, 0, 0)
(0, 1, 0)
(0, 0, 1)
(1, 0, 0)
(Fraction(1, 2), Fraction(1, 2), 0)
(Fraction(1, 2), 0, Fraction(1, 2))
(0, 1, 0)
(0, Fraction(1, 2), Fraction(1, 2))
(0, 0, 1)

poisson_approval.utils.Util.iterator_integers_fixed_sum(d, fixed_sum)[source]

Iterate over vectors of integers with a fixed sum.

Parameters: d (int) – The desired number of integers. In other words, we consider a simplex of dimension d - 1. fixed_sum (int) – The fixed sum. tuple – Each tuple of d integers, whose sum is fixed_sum.

Examples

>>> for t in iterator_integers_fixed_sum(d=3, fixed_sum=2):
...     print(t)
(2, 0, 0)
(1, 1, 0)
(1, 0, 1)
(0, 2, 0)
(0, 1, 1)
(0, 0, 2)

poisson_approval.utils.Util.my_division(x, y)[source]

Division of two numbers, trying to be exact if it is reasonable.

Parameters: x (Number) – y (Number) – The division of x by y. Number

Examples

Typical usages:

>>> my_division(6, 2)
3
>>> my_division(5, 2)
Fraction(5, 2)


If x or y is a float, then the result is a float:

>>> my_division(Fraction(5, 2), 0.1)
25.0
>>> my_division(0.1, Fraction(5, 2))
0.04


If x and y are integers, decimals, fractions or sympy expressions, then the result is symbolic:

>>> my_division(2, Fraction(5, 2))
Fraction(4, 5)
>>> my_division(Decimal('0.1'), Fraction(5, 2))
Fraction(1, 25)
>>> my_division(sp.sqrt(3), 2)
sqrt(3)/2


Possible errors:

>>> my_division(1, 0)
Traceback (most recent call last):
ZeroDivisionError: division by zero
>>> my_division(1, 'foo')
Traceback (most recent call last):
TypeError: unsupported operand type(s) for /: 'Fraction' and 'str'

poisson_approval.utils.Util.my_range(start, end, step)[source]

Parameters: start (Number) – Start value (included). end (Number) – End value (excluded). step (Number) – Increment of the counter.

Examples

>>> for x in my_range(0, 1, Fraction(1, 3)):
...     print(x)
0
1/3
2/3

>>> for x in my_range(1, 0, - Fraction(1, 3)):
...     print(x)
1
2/3
1/3

poisson_approval.utils.Util.my_sign(x)[source]

Sign.

Parameters: x (Number) – Sign of x. int

Examples

>>> my_sign(1.5)
1
>>> my_sign(0)
0
>>> my_sign(-4.2)
-1

poisson_approval.utils.Util.one_over_log_log_t_plus_fourteen(t)[source]

Function 1 / log(log(t + 14)).

This function is provided as an example of update ratio for ProfileCardinal.fictitious_play(). The constant 14 in the denominator is the smallest integer such that f(t = 1) < 1.

Parameters: t (Number) – Number

Examples

>>> one_over_log_log_t_plus_fourteen(2)
0.9806022744169713

poisson_approval.utils.Util.one_over_log_t_plus_one(t)[source]

Function 1 / log(t + 1).

This function is provided as an example of update ratio for ProfileCardinal.fictitious_play(). The constant 1 in the denominator is the smallest integer such that f(t = 2) < 1.

Parameters: t (Number) – Number

Examples

>>> one_over_log_t_plus_one(2)
0.9102392266268373

poisson_approval.utils.Util.one_over_sqrt_t(t)[source]

Function 1 / sqrt(t).

This function is provided as an example of update ratio for ProfileCardinal.fictitious_play().

Parameters: t (Number) – Number

Examples

>>> one_over_sqrt_t(2)
0.7071067811865475

poisson_approval.utils.Util.one_over_t(t)[source]

Function 1 / t.

When used as an update ratio (cf. ProfileCardinal.fictitious_play()), this amounts to computing the arithmetic mean.

Parameters: t (Number) – Number

Examples

>>> one_over_t(2)
Fraction(1, 2)

poisson_approval.utils.Util.probability(factory, n_samples, test, conditional_on=None)[source]

Probability that a random something meets some given test.

Parameters: factory (callable or tuple) – This can be: Either a callable that takes no input and that outputs a (random) something, Or a tuple of such factories (cf. examples below). n_samples (int) – Number of samples. test (callable) – A function that take as input(s) the output(s) of the factory(ies) and that returns a Boolean. conditional_on (callable) – A function that take as input(s) the output(s) of the factory(ies) and that returns a Boolean. Default: always True. The probability that the output(s) generated by factory meet(s) test, conditional on the fact that it meets conditional_on, based on a Monte-Carlo estimation of n_samples trials. float

Examples

In this basic example with one factory, we estimate the probability that a random float between 0 and 1 is greater than .5, conditionally on being greater than .25:

>>> initialize_random_seeds()
>>> def rand_number():
...     return random.random()
>>> probability(factory=rand_number, n_samples=1000,
...             test=lambda x: x > .5, conditional_on=lambda x: x > .25)
0.661


In this example with a tuple of factories, we estimate the probability that a random 2*2 matrix and a random vector of size 2, both with integer coefficients between -10 included and 11 excluded, have a dot product that is null, conditionally on not being null themselves:

>>> initialize_random_seeds()
>>> def rand_matrix():
...     return np.random.randint(-10, 11, (2, 2))
>>> def rand_vector():
...     return np.random.randint(-10, 11, 2)
>>> def test_dot_zero(matrix, vector):
...     return np.all(np.dot(matrix, vector) == 0)
>>> def test_non_trivial(matrix, vector):
...     return not np.all(matrix == 0) and not np.all(vector == 0)
>>> probability(factory=(rand_matrix, rand_vector), n_samples=10000,
...             test=test_dot_zero, conditional_on=test_non_trivial)
0.0003

poisson_approval.utils.Util.product_dict(d_key_possible_values)[source]

Iterable: product of dictionaries.

Parameters: d_key_possible_values – To each key, associate a list of possible values (cf. example below). dict – A dictionary that, to each key, associates one of its possible values. All elements of the Cartesian product are returned this way.

Examples

>>> d_key_possible_values = {'foo': [0, 1], 'bar': ['a', 'b', 'c']}
>>> for d_key_value in product_dict(d_key_possible_values):
...     print(d_key_value)
{'foo': 0, 'bar': 'a'}
{'foo': 0, 'bar': 'b'}
{'foo': 0, 'bar': 'c'}
{'foo': 1, 'bar': 'a'}
{'foo': 1, 'bar': 'b'}
{'foo': 1, 'bar': 'c'}

poisson_approval.utils.Util.rand_integers_fixed_sum(d, fixed_sum)[source]

Generate integers with a given sum (uniformly).

Parameters: d (int) – The desired number of integers. In other words, we consider a simplex of dimension d - 1. fixed_sum (int) – The fixed sum. A numpy array of d integers, whose sum is fixed_sum, and drawn uniformly. numpy.ndarray

Examples

>>> initialize_random_seeds()
>>> rand_integers_fixed_sum(d=6, fixed_sum=100)
array([ 2, 23, 34,  0, 22, 19])

poisson_approval.utils.Util.rand_simplex(d=6)[source]

Draw a random point in the simplex.

Parameters: d (int) – Number of coordinates. In other words, we consider the simplex of dimension d - 1. A numpy array of length d, whose sum is 1. numpy.ndarray

Examples

>>> initialize_random_seeds()
>>> rand_simplex(d=6)  # doctest: +SKIP
array([0.4236548 , 0.12122838, 0.00393032, 0.05394987, 0.11242599, 0.28481063])

poisson_approval.utils.Util.rand_simplex_grid(d, denominator)[source]

Draw a random point in the simplex, with rational coordinates of a given denominator

Parameters: d (int) – Number of coordinates. In other words, we consider the simplex of dimension d - 1. denominator (int) – The coordinates will be fractions with this denominator. A numpy array of length d, whose coordinates are fractions of the given denominator, and whose sum is 1. numpy.ndarray

Examples

>>> initialize_random_seeds()
>>> rand_simplex_grid(d=3, denominator=100)
array([Fraction(13, 50), Fraction(13, 20), Fraction(9, 100)], dtype=object)

poisson_approval.utils.Util.to_callable(o)[source]

Convert to a callable.

Parameters: o (object) – The conversion of o to a callable. callable

Examples

If o is callable, then return o:

>>> def square(x):
...     return x**2
>>> my_function = to_callable(square)
>>> my_function(4)
16


If o is not callable, then return a function *args, **kwargs -> o:

>>> x = 42
>>> my_function = to_callable(x)
>>> my_function('some_argument', keyword='some_value')
42