Initialisation du repository de Beta

venv/lib/python3.12/site-packages/sympy/stats/tests/test_mix.py

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+from sympy.concrete.summations import Sum
+from sympy.core.add import Add
+from sympy.core.mul import Mul
+from sympy.core.numbers import (Integer, oo, pi)
+from sympy.core.power import Pow
+from sympy.core.relational import (Eq, Ne)
+from sympy.core.symbol import (Dummy, Symbol, symbols)
+from sympy.functions.combinatorial.factorials import factorial
+from sympy.functions.elementary.exponential import exp
+from sympy.functions.elementary.miscellaneous import sqrt
+from sympy.functions.elementary.piecewise import Piecewise
+from sympy.functions.special.delta_functions import DiracDelta
+from sympy.functions.special.gamma_functions import gamma
+from sympy.integrals.integrals import Integral
+from sympy.simplify.simplify import simplify
+from sympy.tensor.indexed import (Indexed, IndexedBase)
+from sympy.functions.elementary.piecewise import ExprCondPair
+from sympy.stats import (Poisson, Beta, Exponential, P,
+                        Multinomial, MultivariateBeta)
+from sympy.stats.crv_types import Normal
+from sympy.stats.drv_types import PoissonDistribution
+from sympy.stats.compound_rv import CompoundPSpace, CompoundDistribution
+from sympy.stats.joint_rv import MarginalDistribution
+from sympy.stats.rv import pspace, density
+from sympy.testing.pytest import ignore_warnings
+
+def test_density():
+    x = Symbol('x')
+    l = Symbol('l', positive=True)
+    rate = Beta(l, 2, 3)
+    X = Poisson(x, rate)
+    assert isinstance(pspace(X), CompoundPSpace)
+    assert density(X, Eq(rate, rate.symbol)) == PoissonDistribution(l)
+    N1 = Normal('N1', 0, 1)
+    N2 = Normal('N2', N1, 2)
+    assert density(N2)(0).doit() == sqrt(10)/(10*sqrt(pi))
+    assert simplify(density(N2, Eq(N1, 1))(x)) == \
+        sqrt(2)*exp(-(x - 1)**2/8)/(4*sqrt(pi))
+    assert simplify(density(N2)(x)) == sqrt(10)*exp(-x**2/10)/(10*sqrt(pi))
+
+def test_MarginalDistribution():
+    a1, p1, p2 = symbols('a1 p1 p2', positive=True)
+    C = Multinomial('C', 2, p1, p2)
+    B = MultivariateBeta('B', a1, C[0])
+    MGR = MarginalDistribution(B, (C[0],))
+    mgrc = Mul(Symbol('B'), Piecewise(ExprCondPair(Mul(Integer(2),
+    Pow(Symbol('p1', positive=True), Indexed(IndexedBase(Symbol('C')),
+    Integer(0))), Pow(Symbol('p2', positive=True),
+    Indexed(IndexedBase(Symbol('C')), Integer(1))),
+    Pow(factorial(Indexed(IndexedBase(Symbol('C')), Integer(0))), Integer(-1)),
+    Pow(factorial(Indexed(IndexedBase(Symbol('C')), Integer(1))), Integer(-1))),
+    Eq(Add(Indexed(IndexedBase(Symbol('C')), Integer(0)),
+    Indexed(IndexedBase(Symbol('C')), Integer(1))), Integer(2))),
+    ExprCondPair(Integer(0), True)), Pow(gamma(Symbol('a1', positive=True)),
+    Integer(-1)), gamma(Add(Symbol('a1', positive=True),
+    Indexed(IndexedBase(Symbol('C')), Integer(0)))),
+    Pow(gamma(Indexed(IndexedBase(Symbol('C')), Integer(0))), Integer(-1)),
+    Pow(Indexed(IndexedBase(Symbol('B')), Integer(0)),
+    Add(Symbol('a1', positive=True), Integer(-1))),
+    Pow(Indexed(IndexedBase(Symbol('B')), Integer(1)),
+    Add(Indexed(IndexedBase(Symbol('C')), Integer(0)), Integer(-1))))
+    assert MGR(C) == mgrc
+
+def test_compound_distribution():
+    Y = Poisson('Y', 1)
+    Z = Poisson('Z', Y)
+    assert isinstance(pspace(Z), CompoundPSpace)
+    assert isinstance(pspace(Z).distribution, CompoundDistribution)
+    assert Z.pspace.distribution.pdf(1).doit() == exp(-2)*exp(exp(-1))
+
+def test_mix_expression():
+    Y, E = Poisson('Y', 1), Exponential('E', 1)
+    k = Dummy('k')
+    expr1 = Integral(Sum(exp(-1)*Integral(exp(-k)*DiracDelta(k - 2), (k, 0, oo)
+    )/factorial(k), (k, 0, oo)), (k, -oo, 0))
+    expr2 = Integral(Sum(exp(-1)*Integral(exp(-k)*DiracDelta(k - 2), (k, 0, oo)
+    )/factorial(k), (k, 0, oo)), (k, 0, oo))
+    assert P(Eq(Y + E, 1)) == 0
+    assert P(Ne(Y + E, 2)) == 1
+    with ignore_warnings(UserWarning): ### TODO: Restore tests once warnings are removed
+        assert P(E + Y < 2, evaluate=False).rewrite(Integral).dummy_eq(expr1)
+        assert P(E + Y > 2, evaluate=False).rewrite(Integral).dummy_eq(expr2)