def test_xi():
positions = np.random.rand(10, 3) * 20
# Build reference
c = Correlator(quiet=True)
c.add_point([0, 0, 0], ["hessian"], 5)
for x in positions:
c.add_point(x, ["delta"], 5)
ref = c.cov[:6, 6:]
# Build answer
WG = filters.GaussianFilter(radius=5)
fh = FieldHandler(Ndim=3,
Lbox=2,
dimensions=128,
filter=WG,
Pk=(c.k, c.Pk))
c_hess = C.HessianConstrain([0, 0, 0],
filter=WG,
field_handler=fh,
value=None)
order = [0, 3, 5, 1, 2, 4]
ans = (c_hess.xi(positions) / (fh.sigma(0) * fh.sigma(2)))[:, 0, order].T
# Check
assert_allclose(ref, ans, rtol=5e-2)
def test_field_sigma():
fh = FieldHandler(Ndim=3, Lbox=100, dimensions=128, Pk=(k, Pk))
smoothing_scales = np.geomspace(5, 10, 20)
sigma_th = [fh.sigma(0, filters.TopHatFilter(R)) for R in smoothing_scales]
sigma_exp = [
fh.get_smoothed(filters.TopHatFilter(R)).std() for R in smoothing_scales
]
# Check the field variance
assert_allclose(sigma_th, sigma_exp, rtol=5e-2)