def test_image_auto_conversion_I(self):
stokes = numpy.array(random.uniform(-1.0, 1.0, [3, 4, 128, 128]))
ipf = PolarisationFrame('stokesI')
opf = PolarisationFrame('stokesI')
cir = convert_pol_frame(stokes, ipf, opf)
st = convert_pol_frame(cir, opf, ipf)
assert_array_almost_equal(st.real, stokes, 15)
def test_vis_auto_conversion_I(self):
stokes = numpy.array(random.uniform(-1.0, 1.0, [1000, 3, 1]))
ipf = PolarisationFrame('stokesI')
opf = PolarisationFrame('stokesI')
cir = convert_pol_frame(stokes, ipf, opf, polaxis=2)
st = convert_pol_frame(cir, opf, ipf, polaxis=2)
assert_array_almost_equal(st.real, stokes, 15)
def test_circular_to_linear(self):
stokes = numpy.array(random.uniform(-1.0, 1.0, [3, 4, 128, 128]))
ipf = PolarisationFrame('stokesIQUV')
opf = PolarisationFrame('circular')
cir = convert_pol_frame(stokes, ipf, opf)
wrong_pf = PolarisationFrame('linear')
with self.assertRaises(ValueError):
lin = convert_pol_frame(cir, opf, wrong_pf)
def predict_skycomponent_visibility(
vis: Union[Visibility, BlockVisibility],
sc: Union[Skycomponent, List[Skycomponent]]) -> Visibility:
"""Predict the visibility from a Skycomponent, add to existing visibility, for Visibility or BlockVisibility
:param vis: Visibility or BlockVisibility
:param sc: Skycomponent or list of SkyComponents
:return: Visibility or BlockVisibility
"""
if not isinstance(sc, collections.Iterable):
sc = [sc]
if isinstance(vis, Visibility):
_, im_nchan = list(get_frequency_map(vis, None))
npol = vis.polarisation_frame.npol
for comp in sc:
assert_same_chan_pol(vis, comp)
l, m, n = skycoord_to_lmn(comp.direction, vis.phasecentre)
phasor = simulate_point(vis.uvw, l, m)
for ivis in range(vis.nvis):
for pol in range(npol):
vis.data['vis'][ivis, pol] += comp.flux[im_nchan[ivis],
pol] * phasor[ivis]
elif isinstance(vis, BlockVisibility):
nchan = vis.nchan
npol = vis.npol
k = numpy.array(vis.frequency) / constants.c.to('m/s').value
for comp in sc:
assert_same_chan_pol(vis, comp)
flux = comp.flux
if comp.polarisation_frame != vis.polarisation_frame:
flux = convert_pol_frame(flux, comp.polarisation_frame,
vis.polarisation_frame)
l, m, n = skycoord_to_lmn(comp.direction, vis.phasecentre)
for chan in range(nchan):
phasor = simulate_point(vis.uvw * k[chan], l, m)
for pol in range(npol):
vis.data['vis'][..., chan,
pol] += flux[chan, pol] * phasor[...]
return vis
def predict_skycomponent_blockvisibility(vis: BlockVisibility,
sc: Union[Skycomponent,
List[Skycomponent]],
**kwargs) -> BlockVisibility:
"""Predict the visibility from a Skycomponent, add to existing visibility, for BlockVisibility
:param vis: BlockVisibility
:param sc: Skycomponent or list of SkyComponents
:param spectral_mode: {mfs|channel} (channel)
:return: BlockVisibility
"""
assert type(
vis) is BlockVisibility, "vis is not a BlockVisibility: %r" % vis
if not isinstance(sc, collections.Iterable):
sc = [sc]
nchan = vis.nchan
npol = vis.npol
if not isinstance(sc, collections.Iterable):
sc = [sc]
k = vis.frequency / constants.c.to('m/s').value
for comp in sc:
assert_same_chan_pol(vis, comp)
flux = comp.flux
if comp.polarisation_frame != vis.polarisation_frame:
flux = convert_pol_frame(flux, comp.polarisation_frame,
vis.polarisation_frame)
l, m, n = skycoord_to_lmn(comp.direction, vis.phasecentre)
for chan in range(nchan):
phasor = simulate_point(vis.uvw * k[chan], l, m)
for pol in range(npol):
vis.data['vis'][..., chan,
pol] += flux[chan, pol] * phasor[...]
return vis
