def test_hypergeometric_symbolic():
N, m, n = symbols("N, m, n")
H = Hypergeometric("H", N, m, n)
dens = density(H).dict
expec = E(H > 2)
assert dens == Density(HypergeometricDistribution(N, m, n))
assert dens.subs(N,
5).doit() == Density(HypergeometricDistribution(5, m, n))
assert set(dens.subs({
N: 3,
m: 2,
n: 1
}).doit().keys()) == set([S.Zero, S.One])
assert set(dens.subs({
N: 3,
m: 2,
n: 1
}).doit().values()) == set([Rational(1, 3), Rational(2, 3)])
k = Dummy("k", integer=True)
assert expec.dummy_eq(
Sum(
Piecewise(
(k * binomial(m, k) * binomial(N - m, -k + n) / binomial(N, n),
k > 2),
(0, True),
),
(k, 0, n),
))
def test_hypergeometric_symbolic():
N, m, n = symbols('N, m, n')
H = Hypergeometric('H', N, m, n)
dens = density(H).dict
expec = E(H > 2)
assert dens == Density(HypergeometricDistribution(N, m, n))
assert dens.subs(N, 5).doit() == Density(HypergeometricDistribution(5, m, n))
assert set(dens.subs({N: 3, m: 2, n: 1}).doit().keys()) == set([S(0), S(1)])
assert set(dens.subs({N: 3, m: 2, n: 1}).doit().values()) == set([S(1)/3, S(2)/3])
k = Dummy('k', integer=True)
assert expec.dummy_eq(
Sum(Piecewise((k*binomial(m, k)*binomial(N - m, -k + n)
/binomial(N, n), k > 2), (0, True)), (k, 0, n)))