def test_vis_calc():
# Construct a shell with a single point source at the zenith and confirm against analytic calculation.
ant1_enu = np.array([0, 0, 0])
ant2_enu = np.array([0.0, 14.6, 0])
bl = visibility.baseline(ant1_enu, ant2_enu)
freqs = np.array([1e8])
nfreqs = 1
fov=20 #Deg
## Longitude/Latitude in degrees.
nside=128
ind = 10
center = list(hp.pix2ang(nside, ind, lonlat=True))
centers = [center]
npix = nside**2 * 12
shell = np.zeros((npix, nfreqs))
pix_area = 4* np.pi / float(npix)
shell[ind] = 1 # Jy/pix
shell[ind] *= visibility.jy2Tstr(freqs[0], bm=pix_area) # K
obs = visibility.observatory(latitude, longitude, array=[bl], freqs=freqs)
obs.pointing_centers = centers
obs.set_fov(fov)
# resol = np.sqrt(4*np.pi/float(npix))
obs.set_beam('uniform')
visibs = obs.make_visibilities(shell)
print visibs
nt.assert_true(np.real(visibs) == 1.0) #Unit point source at zenith
def test_offzenith_vis():
# Construct a shell with a single point source a known position off from zenith.
# Similar to test_vis_calc, but set the pointing center 5deg off from the zenith and adjust analytic calculation
freqs = [1.0e8]
Nfreqs = 1
fov = 60
ant1_enu = np.array([0, 0, 0])
ant2_enu = np.array([0.0, 140.6, 0])
bl = visibility.baseline(ant1_enu, ant2_enu)
Nside=128
ind = 9081
center = list(hp.pix2ang(Nside, ind, lonlat=True))
centers = [center]
Npix = Nside**2 * 12
pix_area = 4*np.pi/float(Npix)
shell = np.zeros((Npix, Nfreqs))
# Choose an index 5 degrees off from the pointing center
phi, theta = hp.pix2ang(Nside, ind, lonlat=True)
ind = hp.ang2pix(Nside, phi, theta-5, lonlat=True)
shell[ind] = 1 # Jy/pix
shell[ind] *= visibility.jy2Tstr(freqs[0], pix_area) # K
obs = visibility.observatory(latitude, longitude, array=[bl], freqs=freqs)
obs.pointing_centers = [[phi, theta]]
obs.set_fov(fov)
resol = np.sqrt(pix_area)
obs.set_beam('uniform')
vis_calc = obs.make_visibilities(shell)
phi_new, theta_new = hp.pix2ang(Nside, ind, lonlat=True)
src_az, src_za = np.radians(phi - phi_new), np.radians(theta-theta_new)
src_l = np.sin(src_az) * np.sin(src_za)
src_m = np.cos(src_az) * np.sin(src_za)
src_n = np.cos(src_za)
u, v, w = bl.get_uvw(freqs[0])
vis_analytic = (1) * np.exp(2j * np.pi * (u*src_l + v*src_m + w*src_n))
print(vis_analytic)
print(vis_calc)
nt.assert_true(np.isclose(vis_analytic, vis_calc, atol=1e-3))
inds = time_arr xind, yind = np.meshgrid(inds, inds) diff_inds = xind-yind means, bins, binnums = binned_statistic(diff_inds.flatten(), np.real(cov).flatten(), bins=Nbins) lag_bins = ((bins[1:] + bins[:-1])/2.) #pl.plot(bins[1:], means) return means, lag_bins # Observatory latitude = -30.7215277777 longitude = 21.4283055554 fov = 180 #Deg ant1_enu = np.array([0, 0, 0]) ant2_enu = np.array([0.0, 14.6, 0]) bl = visibility.baseline(ant1_enu, ant2_enu) # Time #Ntimes = 500 #t0 = 2451545.0 #Start at J2000 epoch #dt_min_short = 30.0/60. #dt_min_long = 10.0 #dt_days_short = dt_min_short * 1/60. * 1/24. #dt_days_long = dt_min_long * 1/60. * 1/24. #time_arr_short = np.arange(Ntimes) * dt_days_short + t0 #time_arr_long = np.arange(Ntimes) * dt_days_long + t0 # #time_arr = time_arr_short t0 = 2451545.0 #Start at J2000 epoch #Ntimes = 7854 # 24 hours in 11 sec chunks
antnums = sel['antenna_nums']
if isinstance(antnums, str):
antnums = eval(sel['antenna_nums'])
if isinstance(antnums, int):
antnums = [antnums]
bls = [(a1, a2) for (a1, a2) in bls if a1 in antnums or a2 in antnums]
uv_obj.antenna_nums = antnums
if 'redundancy' in sel:
red_tol = sel['redundancy']
reds, vec_bin_centers, lengths = uvutils.get_antenna_redundancies(anums, enu, tol=red_tol, include_autos=False)
bls = [r[0] for r in reds]
bls = [uvutils.baseline_to_antnums(bl_ind, Nants) for bl_ind in bls]
uv_obj.Nants_data = np.unique(bls).size
for (a1, a2) in bls:
i1, i2 = np.where(anums == a1), np.where(anums == a2)
array.append(visibility.baseline(enu[i1], enu[i2]))
bl_array.append(uvutils.antnums_to_baseline(a1, a2, Nants))
Nbls = len(bl_array)
uv_obj.Nbls = Nbls
uv_obj.Nblts = Nbls * Ntimes
bl_array = np.array(bl_array)
freqs = freq_dict['freq_array'][0] #Hz
obs = visibility.observatory(np.degrees(lat), np.degrees(lon), array=array, freqs=freqs)
obs.set_fov(fov)
print("Observatory built.")
print("Nbls: ", Nbls)
print("Ntimes: ", Ntimes)
sys.stdout.flush()
diff_inds = xind - yind
means, bins, binnums = binned_statistic(diff_inds.flatten(),
np.real(cov).flatten(),
bins=Nbins)
lag_bins = ((bins[1:] + bins[:-1]) / 2.)
#pl.plot(bins[1:], means)
return means, lag_bins
# Observatory
latitude = -30.7215277777
longitude = 21.4283055554
fov = 45 #Deg
ant1_enu = np.array([0, 0, 0])
ant2_enu = np.array([0.0, 14.6, 0])
bl = visibility.baseline(ant1_enu, ant2_enu)
lengths = [14.6, 50.0, 100.0]
bls = []
for l in lengths:
ant2_enu = np.array([0.0, l, 0.0])
bls.append(visibility.baseline(ant1_enu, ant2_enu))
# Time
Ntimes = 500
t0 = 2451545.0 #Start at J2000 epoch
dt_min_short = 30.0 / 60.
dt_min_long = 10.0
dt_days_short = dt_min_short * 1 / 60. * 1 / 24.
dt_days_long = dt_min_long * 1 / 60. * 1 / 24.
time_arr_short = np.arange(Ntimes) * dt_days_short + t0