frequency=frequency,
nchan=nfreqwin,
cellsize=cellsize,
phasecentre=phasecentre)
beam = create_low_test_beam(beam, use_local=False)
original_gleam_components = create_low_test_skycomponents_from_gleam(
flux_limit=flux_limit,
phasecentre=phasecentre,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesI'),
radius=0.15)
all_components = apply_beam_to_skycomponent(original_gleam_components,
beam)
all_components = filter_skycomponents_by_flux(all_components,
flux_min=flux_limit)
all_components = sorted(all_components,
key=lambda comp: numpy.max(comp.flux),
reverse=True)
print("Number of components in simulation %d" % len(all_components))
screen = import_image_from_fits(
arl_path('data/models/test_mpc_screen.fits'))
all_gaintables = create_gaintable_from_screen(block_vis, all_components,
screen)
all_skymodel = [
SkyModel(components=[all_components[i]], gaintable=all_gaintables[i])
for i, sm in enumerate(all_components)
]
def actualSetup(self, nsources=None, nvoronoi=None):
n_workers = 8
# Set up the observation: 10 minutes at transit, with 10s integration.
# Skip 5/6 points to avoid outstation redundancy
nfreqwin = 1
ntimes = 3
self.rmax = 2500.0
dec = -40.0 * u.deg
frequency = [1e8]
channel_bandwidth = [0.1e8]
times = numpy.linspace(-10.0, 10.0,
ntimes) * numpy.pi / (3600.0 * 12.0)
phasecentre = SkyCoord(ra=+0.0 * u.deg,
dec=dec,
frame='icrs',
equinox='J2000')
low = create_named_configuration('LOWBD2', rmax=self.rmax)
centre = numpy.mean(low.xyz, axis=0)
distance = numpy.hypot(low.xyz[:, 0] - centre[0],
low.xyz[:, 1] - centre[1],
low.xyz[:, 2] - centre[2])
lowouter = low.data[distance > 1000.0][::6]
lowcore = low.data[distance < 1000.0][::3]
low.data = numpy.hstack((lowcore, lowouter))
blockvis = create_blockvisibility(
low,
times,
frequency=frequency,
channel_bandwidth=channel_bandwidth,
weight=1.0,
phasecentre=phasecentre,
polarisation_frame=PolarisationFrame("stokesI"),
zerow=True)
vis = convert_blockvisibility_to_visibility(blockvis)
advice = advise_wide_field(vis, guard_band_image=2.0, delA=0.02)
cellsize = advice['cellsize']
npixel = advice['npixels2']
small_model = create_image_from_visibility(blockvis,
npixel=512,
frequency=frequency,
nchan=nfreqwin,
cellsize=cellsize,
phasecentre=phasecentre)
vis.data['imaging_weight'][...] = vis.data['weight'][...]
vis = weight_list_serial_workflow([vis], [small_model])[0]
vis = taper_list_serial_workflow([vis], 3 * cellsize)[0]
blockvis = convert_visibility_to_blockvisibility(vis)
# ### Generate the model from the GLEAM catalog, including application of the primary beam.
beam = create_image_from_visibility(blockvis,
npixel=npixel,
frequency=frequency,
nchan=nfreqwin,
cellsize=cellsize,
phasecentre=phasecentre)
beam = create_low_test_beam(beam, use_local=False)
flux_limit = 0.5
original_gleam_components = create_low_test_skycomponents_from_gleam(
flux_limit=flux_limit,
phasecentre=phasecentre,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesI'),
radius=0.15)
all_components = apply_beam_to_skycomponent(original_gleam_components,
beam)
all_components = filter_skycomponents_by_flux(all_components,
flux_min=flux_limit)
voronoi_components = filter_skycomponents_by_flux(all_components,
flux_min=1.5)
def max_flux(elem):
return numpy.max(elem.flux)
voronoi_components = sorted(voronoi_components,
key=max_flux,
reverse=True)
if nsources is not None:
all_components = [all_components[0]]
if nvoronoi is not None:
voronoi_components = [voronoi_components[0]]
self.screen = import_image_from_fits(
arl_path('data/models/test_mpc_screen.fits'))
all_gaintables = create_gaintable_from_screen(blockvis, all_components,
self.screen)
gleam_skymodel_noniso = [
SkyModel(components=[all_components[i]],
gaintable=all_gaintables[i])
for i, sm in enumerate(all_components)
]
# ### Now predict the visibility for each skymodel and apply the gaintable for that skymodel,
# returning a list of visibilities, one for each skymodel. We then sum these to obtain
# the total predicted visibility. All images and skycomponents in the same skymodel
# get the same gaintable applied which means that in this case each skycomponent has a separate gaintable.
self.all_skymodel_noniso_vis = convert_blockvisibility_to_visibility(
blockvis)
ngroup = n_workers
future_vis = arlexecute.scatter(self.all_skymodel_noniso_vis)
chunks = [
gleam_skymodel_noniso[i:i + ngroup]
for i in range(0, len(gleam_skymodel_noniso), ngroup)
]
for chunk in chunks:
result = predict_skymodel_list_arlexecute_workflow(future_vis,
chunk,
context='2d',
docal=True)
work_vis = arlexecute.compute(result, sync=True)
for w in work_vis:
self.all_skymodel_noniso_vis.data['vis'] += w.data['vis']
assert numpy.max(
numpy.abs(self.all_skymodel_noniso_vis.data['vis'])) > 0.0
self.all_skymodel_noniso_blockvis = convert_visibility_to_blockvisibility(
self.all_skymodel_noniso_vis)
# ### Remove weaker of components that are too close (0.02 rad)
idx, voronoi_components = remove_neighbouring_components(
voronoi_components, 0.02)
model = create_image_from_visibility(blockvis,
npixel=npixel,
frequency=frequency,
nchan=nfreqwin,
cellsize=cellsize,
phasecentre=phasecentre)
# Use the gaintable for the brightest component as the starting gaintable
all_gaintables[0].gain[...] = numpy.conjugate(
all_gaintables[0].gain[...])
all_gaintables[0].gain[...] = 1.0 + 0.0j
self.theta_list = initialize_skymodel_voronoi(model,
voronoi_components,
all_gaintables[0])
frequency=frequency,
nchan=nfreqwin,
cellsize=cellsize,
phasecentre=phasecentre)
beam = create_low_test_beam(beam)
original_gleam_components = create_low_test_skycomponents_from_gleam(
flux_limit=flux_limit,
phasecentre=phasecentre,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesI'),
radius=0.2)
pb_gleam_components = apply_beam_to_skycomponent(original_gleam_components,
beam)
bright_components = filter_skycomponents_by_flux(pb_gleam_components,
flux_min=0.3)
all_components = filter_skycomponents_by_flux(pb_gleam_components,
flux_min=flux_limit)
show_image(beam,
components=bright_components,
cm='Greys',
title='Primary beam plus bright components',
vmax=3.0)
lprint("Number of bright components %d" % len(bright_components))
# In[7]:
idx, filtered_bright_components = remove_neighbouring_components(
bright_components, 0.01)
