def gaussianfg(ctx):
"""Generate a full-sky Gaussian random field for synchrotron emission.
"""
import numpy as np
from cora.core import skysim
from cora.util import hputil
from cora.foreground import galaxy
fsyn = galaxy.FullSkySynchrotron()
fpol = galaxy.FullSkyPolarisedSynchrotron()
# Set frequency parameters
fsyn.frequencies = ctx.obj.freq
nfreq = len(fsyn.frequencies)
nside = ctx.obj.nside
lmax = 3 * nside
npol = 4 if ctx.obj.full_pol else 1
cv_fg = np.zeros((lmax + 1, npol, nfreq, npol, nfreq))
cv_fg[:, 0, :, 0, :] = skysim.clarray(fsyn.angular_powerspectrum, lmax,
fsyn.nu_pixels)
if ctx.obj.full_pol:
cv_fg[:, 1, :, 1, :] = skysim.clarray(fpol.angular_powerspectrum, lmax,
fsyn.nu_pixels)
cv_fg[:, 2, :, 2, :] = skysim.clarray(fpol.angular_powerspectrum, lmax,
fsyn.nu_pixels)
cv_fg = cv_fg.reshape(lmax + 1, npol * nfreq, npol * nfreq)
alms = skysim.mkfullsky(cv_fg, nside,
alms=True).reshape(npol, nfreq, lmax + 1, lmax + 1)
alms = alms.transpose((1, 0, 2, 3))
maps = hputil.sphtrans_inv_sky(alms, nside)
write_map(ctx.obj.filename, maps, fsyn.frequencies, ctx.obj.freq_width,
ctx.obj.include_pol)
def test_corr_foreground():
"""Test that the foreground power spectrum is being calculated correctly.
Correct here is referenced to a specific version believed to have no errors.
"""
cr = galaxy.FullSkySynchrotron()
aps1 = cr.angular_powerspectrum(np.arange(1000), 800.0, 800.0)
assert len(aps1) == 1000
assert np.allclose(aps1.sum(), 75.47681191093129,
rtol=1e-7) # Calculated for commit 02f4d1cd3f402d
fa = np.linspace(400.0, 800.0, 64)
aps2 = cr.angular_powerspectrum(
np.arange(1000)[:, None, None], fa[None, :, None], fa[None, None, :])
assert aps2.shape == (1000, 64, 64)
# Calculated for commit 02f4d1cd3f402d
v1 = 9.690708728692975e-06 # l=400, fi=40, fj=40
v2 = 0.00017630767166797886 # l=200, fi=10, fj=40
assert np.allclose(aps2[400, 40, 40], v1, rtol=1e-7)
assert np.allclose(aps2[200, 10, 40], v2, rtol=1e-7)
def foreground_model(lmax, frequencies, npol, pol_frac=1.0, pol_length=None):
fsyn = galaxy.FullSkySynchrotron()
fps = PointSources()
nfreq = frequencies.size
cv_fg = np.zeros((npol, npol, lmax + 1, nfreq, nfreq))
cv_fg[0, 0] = skysim.clarray(fsyn.angular_powerspectrum, lmax, frequencies)
if npol >= 3:
fpol = galaxy.FullSkyPolarisedSynchrotron()
if pol_length is not None:
fpol.zeta = pol_length
cv_fg[1, 1] = pol_frac * skysim.clarray(fpol.angular_powerspectrum,
lmax, frequencies)
cv_fg[2, 2] = pol_frac * skysim.clarray(fpol.angular_powerspectrum,
lmax, frequencies)
cv_fg[0, 0] += skysim.clarray(fps.angular_powerspectrum, lmax, frequencies)
return cv_fg