def test_data_processing_inequality_wyner(dist):
"""
given X - Y - Z:
C(X:Z) <= C(X:Y)
"""
c_xy = C(dist, [[0], [1]])
c_xz = C(dist, [[0], [2]])
assert c_xz <= c_xy + 10 * epsilon
def test_cis2(dist):
"""
Test that the common informations are ordered correctly.
"""
k = K(dist)
j = J(dist)
b = B(dist)
c = C(dist)
g = G(dist)
f = F(dist)
m = M(dist)
assert k <= j + epsilon
assert j <= b + epsilon
assert b <= c + epsilon
assert c <= g + epsilon
assert g <= f + epsilon
assert f <= m + epsilon
def test_wci1(rvs, crvs, val):
"""
Test against known values.
"""
c = C(xor, rvs, crvs)
assert float(c) == pytest.approx(val, abs=1e-4)