def test_sample_texture_range():
world = CylinderWorld(rng=np.random.RandomState(SEED))
alpha0, alpha1 = 0.5, 0.75
alphas = np.linspace(alpha0, alpha1, 100000)
smpls = world.sample_texture(alphas)
smpl_range = world.sample_texture_range(alpha0, alpha1)
assert np.abs(np.mean(smpls) - smpl_range) < 1e-5
def test_sample_texture_derivative():
world = CylinderWorld(rng=np.random.RandomState(SEED))
eta = 1e-6
alpha = 0.5
smpl0 = world.sample_texture(alpha - 0.5 * eta)
smpl1 = world.sample_texture(alpha + 0.5 * eta)
dsmpl_num = (smpl1 - smpl0) / eta
dsmpl_direct = world.sample_texture_derivative(alpha)
assert np.abs(dsmpl_direct - dsmpl_num) < 1e-5