def test_empty_uvdata(self):
# Make sure that empty_uvdata() can produce a UVData object
nfreqs = 150
ntimes = 20
ants = {0: (1.0, 2.0, 3.0), 1: (3.0, 4.0, 5.0)}
antpairs1 = [(0, 1), (1, 0), (1, 1)]
antpairs2 = [(0, 1), (1, 0), (1, 1), (0, 1)] # duplicate baseline
# Build object and check that data_array has correct dimensions
uvd = io.empty_uvdata(nfreqs, ntimes, ants=ants, antpairs=antpairs1)
self.assertEqual(uvd.data_array.shape, (len(antpairs1) * ntimes, 1, nfreqs, 1))
# Check that duplicate baselines get filtered out
uvd = io.empty_uvdata(nfreqs, ntimes, ants=ants, antpairs=antpairs2)
self.assertEqual(uvd.data_array.shape,
(len(antpairs1) * ntimes, 1, nfreqs, 1))
def test_antpair_order(self):
nfreqs = 10
ntimes = 10
ants = {j: tuple(np.random.rand(3)) for j in range(10)}
uvd = io.empty_uvdata(nfreqs, ntimes, ants=ants)
for ant1, ant2 in uvd.get_antpairs():
self.assertLessEqual(ant1,ant2)
def uvdataJD():
return io.empty_uvdata(nfreq=NFREQ,
integration_time=sday.to('s') / NTIMES,
ntimes=NTIMES,
ants={
0: (0, 0, 0),
},
start_time=2456659)
def uvdata2():
return io.empty_uvdata(
nfreq=NFREQ,
integration_time=sday.to('s') / NTIMES,
ntimes=NTIMES,
ants={
0: (0, 0, 0),
1: (1, 1, 0)
},
)
def test_bad_antpairs(self):
# Make sure that empty_uvdata() can produce a UVData object
nfreqs = 150
ntimes = 20
ants = {0: (1., 2., 3.), 1: (3., 4., 5.)}
antpairs1 = [(0, 1), (1, 0), (1, 1), 1]
with self.assertRaises(TypeError):
uvd = io.empty_uvdata(nfreqs,
ntimes,
ants=ants,
antpairs=antpairs1)
def empty_uvdata(ants=None,
nfreq=20,
ntimes=20,
bandwidth=0.2e8,
integration_time=40.,
start_time=2458902.33333,
start_freq=1.e8,
**kwargs):
"""
Generate empty UVData object with the right shape.
Parameters
----------
ants (dict): None
A dictionary mapping an integer to a three-tuple of ENU co-ordinates for
each antenna. These antennas can be down-selected via keywords.
ntimes : int, optional
Number of time samples. Default: 20.
bandwidth : float
Total bandwidth, in Hz. Default: 0.2e8
integration_time : float, optional
Integration time per time sample. Default: 40.
start_time : float, optional
Start date of observations, as Julian date. Default: 2458902.33333
(20:00 UTC on 2020-02-22)
start_freq : float, optional
Initial frequency channel, in Hz. Default: 1.e8.
**kwargs : args
Other arguments to be passed to `hera_sim.io.empty_uvdata`.
Returns
-------
uvd : UVData
Returns an empty UVData
"""
uvd = io.empty_uvdata(nfreq=nfreq,
start_freq=start_freq,
channel_width=bandwidth / nfreq,
start_time=start_time,
integration_time=integration_time,
ntimes=ntimes,
ants=ants,
**kwargs)
# Add missing parameters
uvd._x_orientation.value = 'east'
return uvd