def actualSetup(self,
sky_pol_frame='stokesIQUV',
data_pol_frame='linear',
f=[100.0, 50.0, -10.0, 40.0]):
f = numpy.array(f)
self.flux = numpy.array([f, 0.8 * f, 0.6 * f])
# The phase centre is absolute and the component is specified relative (for now).
# This means that the component should end up at the position phasecentre+compredirection
self.phasecentre = SkyCoord(ra=+180.0 * u.deg,
dec=-35.0 * u.deg,
frame='icrs',
equinox='J2000')
self.compabsdirection = SkyCoord(ra=+181.0 * u.deg,
dec=-35.0 * u.deg,
frame='icrs',
equinox='J2000')
self.comp = Skycomponent(
direction=self.compabsdirection,
frequency=self.frequency,
flux=self.flux,
polarisation_frame=PolarisationFrame(sky_pol_frame))
self.vis = create_blockvisibility(
self.lowcore,
self.times,
self.frequency,
phasecentre=self.phasecentre,
channel_bandwidth=self.channel_bandwidth,
weight=1.0,
polarisation_frame=PolarisationFrame(data_pol_frame))
self.vis = predict_skycomponent_blockvisibility(self.vis, self.comp)
def ingest_visibility(self, freq=None, chan_width=None, times=None, reffrequency=None, add_errors=False,
block=True):
if freq is None:
freq = [1e8]
if times is None:
ntimes = 5
times = numpy.linspace(-numpy.pi / 3.0, numpy.pi / 3.0, ntimes)
if chan_width is None:
chan_width = [1e6]
if reffrequency is None:
reffrequency = [1e8]
lowcore = create_named_configuration('LOWBD2-CORE')
frequency = numpy.array([freq])
channel_bandwidth = numpy.array([chan_width])
phasecentre = SkyCoord(ra=+180.0 * u.deg, dec=-60.0 * u.deg, frame='icrs', equinox='J2000')
if block:
vt = create_blockvisibility(lowcore, times, frequency, channel_bandwidth=channel_bandwidth,
weight=1.0, phasecentre=phasecentre,
polarisation_frame=PolarisationFrame("stokesI"))
else:
vt = create_visibility(lowcore, times, frequency, channel_bandwidth=channel_bandwidth,
weight=1.0, phasecentre=phasecentre,
polarisation_frame=PolarisationFrame("stokesI"))
cellsize = 0.001
model = create_image_from_visibility(vt, npixel=self.npixel, cellsize=cellsize, npol=1,
frequency=reffrequency, phasecentre=phasecentre,
polarisation_frame=PolarisationFrame("stokesI"))
flux = numpy.array([[100.0]])
facets = 4
rpix = model.wcs.wcs.crpix - 1.0
spacing_pixels = self.npixel // facets
centers = [-1.5, -0.5, 0.5, 1.5]
comps = list()
for iy in centers:
for ix in centers:
p = int(round(rpix[0] + ix * spacing_pixels * numpy.sign(model.wcs.wcs.cdelt[0]))), \
int(round(rpix[1] + iy * spacing_pixels * numpy.sign(model.wcs.wcs.cdelt[1])))
sc = pixel_to_skycoord(p[0], p[1], model.wcs, origin=1)
comp = create_skycomponent(flux=flux, frequency=frequency, direction=sc,
polarisation_frame=PolarisationFrame("stokesI"))
comps.append(comp)
if block:
predict_skycomponent_blockvisibility(vt, comps)
else:
predict_skycomponent_visibility(vt, comps)
insert_skycomponent(model, comps)
self.model = copy_image(model)
self.empty_model = create_empty_image_like(model)
export_image_to_fits(model, '%s/test_pipeline_bags_model.fits' % self.dir)
if add_errors:
# These will be the same for all calls
numpy.random.seed(180555)
gt = create_gaintable_from_blockvisibility(vt)
gt = simulate_gaintable(gt, phase_error=1.0, amplitude_error=0.0)
vt = apply_gaintable(vt, gt)
return vt
def ingest_unittest_visibility(config,
frequency,
channel_bandwidth,
times,
vis_pol,
phasecentre,
block=False):
if block:
vt = create_blockvisibility(config,
times,
frequency,
channel_bandwidth=channel_bandwidth,
phasecentre=phasecentre,
weight=1.0,
polarisation_frame=vis_pol)
else:
vt = create_visibility(config,
times,
frequency,
channel_bandwidth=channel_bandwidth,
phasecentre=phasecentre,
weight=1.0,
polarisation_frame=vis_pol)
vt.data['vis'][...] = 0.0
return vt
def setUp(self):
self.dir = './test_results'
os.makedirs(self.dir, exist_ok=True)
lowcore = create_named_configuration('LOWBD2-CORE')
times = numpy.arange(-3.0, +3.0, 1.0) * numpy.pi / 12.0
vnchan = 8
frequency = numpy.linspace(0.8e8, 1.20e8, vnchan)
channel_bandwidth = numpy.array(vnchan * [frequency[1] - frequency[0]])
# Define the component and give it some polarisation and spectral behaviour
f = numpy.array([100.0, 20.0, -10.0, 1.0])
self.flux = numpy.array(
[f, 0.9 * f, 0.8 * f, 0.7 * f, 0.6 * f, 0.5 * f, 0.4 * f, 0.3 * f])
self.phasecentre = SkyCoord(ra=+15.0 * u.deg,
dec=-35.0 * u.deg,
frame='icrs',
equinox='J2000')
self.compabsdirection = SkyCoord(ra=17.0 * u.deg,
dec=-36.5 * u.deg,
frame='icrs',
equinox='J2000')
self.comp = create_skycomponent(flux=self.flux,
frequency=frequency,
direction=self.compabsdirection)
self.image = create_test_image(
frequency=frequency,
phasecentre=self.phasecentre,
cellsize=0.001,
polarisation_frame=PolarisationFrame('stokesIQUV'))
self.blockvis = create_blockvisibility_iterator(
lowcore,
times=times,
frequency=frequency,
channel_bandwidth=channel_bandwidth,
phasecentre=self.phasecentre,
weight=1,
polarisation_frame=PolarisationFrame('linear'),
integration_time=1.0,
number_integrations=1,
predict=predict_2d,
components=self.comp,
phase_error=0.1,
amplitude_error=0.01,
sleep=1.0)
self.vis = create_blockvisibility(
lowcore,
times=times,
frequency=frequency,
channel_bandwidth=channel_bandwidth,
phasecentre=self.phasecentre,
weight=1,
polarisation_frame=PolarisationFrame('stokesIQUV'),
integration_time=1.0)
self.vis = predict_2d(self.vis, self.image)
def actualSetUp(self, times=None):
if times is not None:
self.times = times
self.vis = create_blockvisibility(self.lowcore, self.times, self.frequency,
channel_bandwidth=self.channel_bandwidth, phasecentre=self.phasecentre,
weight=1.0)
self.gaintable = create_gaintable_from_blockvisibility(self.vis, time_slice='auto')
def create_blockvisibility_iterator(config: Configuration, times: numpy.array, frequency: numpy.array,
channel_bandwidth, phasecentre: SkyCoord, weight: float = 1,
polarisation_frame=PolarisationFrame('stokesI'), integration_time=1.0,
number_integrations=1, predict=predict_timeslice, model=None, components=None,
phase_error=0.0, amplitude_error=0.0, sleep=0.0, **kwargs) -> BlockVisibility:
""" Create a sequence of Visibilities and optionally predicting and coalescing
This is useful mainly for performing large simulations. Do something like::
vis_iter = create_blockvisibility_iterator(config, times, frequency, channel_bandwidth, phasecentre=phasecentre,
weight=1.0, integration_time=30.0, number_integrations=3)
for i, vis in enumerate(vis_iter):
if i == 0:
fullvis = vis
else:
fullvis = append_visibility(fullvis, vis)
:param config: Configuration of antennas
:param times: hour angles in radians
:param frequency: frequencies (Hz] Shape [nchan]
:param weight: weight of a single sample
:param phasecentre: phasecentre of observation
:param npol: Number of polarizations
:param integration_time: Integration time ('auto' or value in s)
:param number_integrations: Number of integrations to be created at each time.
:param model: Model image to be inserted
:param components: Components to be inserted
:param sleep_time: Time to sleep between yields
:return: Visibility
"""
for time in times:
actualtimes = time + numpy.arange(0, number_integrations) * integration_time * numpy.pi / 43200.0
bvis = create_blockvisibility(config, actualtimes, frequency=frequency, phasecentre=phasecentre, weight=weight,
polarisation_frame=polarisation_frame, integration_time=integration_time,
channel_bandwidth=channel_bandwidth)
if model is not None:
vis = predict(bvis, model, **kwargs)
bvis = convert_visibility_to_blockvisibility(vis)
if components is not None:
bvis = predict_skycomponent_blockvisibility(bvis, components)
# Add phase errors
if phase_error > 0.0 or amplitude_error > 0.0:
gt = create_gaintable_from_blockvisibility(bvis)
gt = simulate_gaintable(gt=gt, phase_error=phase_error, amplitude_error=amplitude_error)
vis = apply_gaintable(bvis, gt)
import time
time.sleep(sleep)
yield bvis
def test_convert_blockvisibility(self):
self.vis = create_blockvisibility(
self.lowcore,
self.times,
self.frequency,
phasecentre=self.phasecentre,
weight=1.0,
channel_bandwidth=self.channel_bandwidth)
vis = convert_blockvisibility_to_visibility(self.vis)
assert vis.nvis == len(vis.time)
assert numpy.unique(vis.time).size == self.vis.time.size # pylint: disable=no-member
def setUp(self):
self.lowcore = create_named_configuration('LOWBD2-CORE')
self.times = (numpy.pi / 43200.0) * numpy.arange(0.0, 30 * 3.76, 3.76)
df = 27343.75000
self.frequency = numpy.array([1e8 - df, 1e8, 1e8 + df])
self.channel_bandwidth = numpy.array([27343.75, 27343.75, 27343.75])
self.phasecentre = SkyCoord(ra=+0.0 * u.deg, dec=-35.0 * u.deg, frame='icrs', equinox='J2000')
self.blockvis = create_blockvisibility(self.lowcore, self.times, self.frequency, phasecentre=self.phasecentre,
weight=1.0, polarisation_frame=PolarisationFrame('stokesI'),
channel_bandwidth=self.channel_bandwidth)
def test_coalesce_decoalesce_singletime(self):
self.times = numpy.array([0.0])
self.blockvis = create_blockvisibility(self.lowcore, self.times, self.frequency, phasecentre=self.phasecentre,
weight=1.0, polarisation_frame=PolarisationFrame('stokesI'),
channel_bandwidth=self.channel_bandwidth)
# Fill in the vis values so each can be uniquely identified
self.blockvis.data['vis'] = range(self.blockvis.nvis)
cvis = coalesce_visibility(self.blockvis, time_coal=1.0)
assert numpy.min(cvis.frequency) == numpy.min(self.frequency)
assert numpy.min(cvis.frequency) > 0.0
dvis = decoalesce_visibility(cvis)
assert dvis.nvis == self.blockvis.nvis
def actualSetUp(self, times=None):
if times is not None:
self.times = times
self.vis = create_visibility(self.lowcore, self.times, self.frequency,
channel_bandwidth=self.channel_bandwidth, phasecentre=self.phasecentre,
weight=1.0)
self.vis.data['vis'][:,0] = self.vis.time
self.blockvis = create_blockvisibility(self.lowcore, self.times, self.frequency,
channel_bandwidth=self.channel_bandwidth, phasecentre=self.phasecentre,
weight=1.0)
self.blockvis.data['vis'][...] = 1.0
def actualSetup(self, sky_pol_frame='stokesIQUV', data_pol_frame='linear'):
self.comp = Skycomponent(
direction=self.compabsdirection,
frequency=self.frequency,
flux=self.flux,
polarisation_frame=PolarisationFrame(sky_pol_frame))
self.vis = create_blockvisibility(
self.lowcore,
self.times,
self.frequency,
phasecentre=self.phasecentre,
channel_bandwidth=self.channel_bandwidth,
weight=1.0,
polarisation_frame=PolarisationFrame(data_pol_frame))
self.vis = predict_skycomponent_blockvisibility(self.vis, self.comp)
def test_create_generic_blockvisibility_graph(self):
self.blockvis = [
create_blockvisibility(
self.lowcore,
self.times,
self.frequency,
phasecentre=self.phasecentre,
channel_bandwidth=self.channel_bandwidth,
weight=1.0,
polarisation_frame=PolarisationFrame('stokesI'))
]
self.blockvis = \
create_generic_blockvisibility_graph(predict_skycomponent_blockvisibility, vis_graph_list=self.blockvis,
sc=self.comp)[0].compute()
assert numpy.max(numpy.abs(self.blockvis[0].vis)) > 0.0
def actualSetup(self,
sky_pol_frame='stokesIQUV',
data_pol_frame='linear',
f=None,
vnchan=3):
self.lowcore = create_named_configuration('LOWBD2-CORE')
self.times = (numpy.pi / 43200.0) * numpy.linspace(0.0, 30.0, 3)
self.frequency = numpy.linspace(1.0e8, 1.1e8, vnchan)
self.channel_bandwidth = numpy.array(
vnchan * [self.frequency[1] - self.frequency[0]])
if f is None:
f = [100.0, 50.0, -10.0, 40.0]
if sky_pol_frame == 'stokesI':
f = [100.0]
self.flux = numpy.outer(
numpy.array(
[numpy.power(freq / 1e8, -0.7) for freq in self.frequency]), f)
# The phase centre is absolute and the component is specified relative (for now).
# This means that the component should end up at the position phasecentre+compredirection
self.phasecentre = SkyCoord(ra=+180.0 * u.deg,
dec=-35.0 * u.deg,
frame='icrs',
equinox='J2000')
self.compabsdirection = SkyCoord(ra=+181.0 * u.deg,
dec=-35.0 * u.deg,
frame='icrs',
equinox='J2000')
self.comp = Skycomponent(
direction=self.compabsdirection,
frequency=self.frequency,
flux=self.flux,
polarisation_frame=PolarisationFrame(sky_pol_frame))
self.vis = create_blockvisibility(
self.lowcore,
self.times,
self.frequency,
phasecentre=self.phasecentre,
channel_bandwidth=self.channel_bandwidth,
weight=1.0,
polarisation_frame=PolarisationFrame(data_pol_frame))
self.vis = predict_skycomponent_visibility(self.vis, self.comp)
def ingest_visibility(self, freq=1e8, chan_width=1e6, times=None, reffrequency=None, add_errors=False):
if times is None:
times = [0.0]
if reffrequency is None:
reffrequency = [1e8]
lowcore = create_named_configuration('LOWBD2-CORE')
frequency = numpy.array([freq])
channel_bandwidth = numpy.array([chan_width])
# phasecentre = SkyCoord(ra=+180.0 * u.deg, dec=-60.0 * u.deg, frame='icrs', equinox='J2000')
# Observe at zenith to ensure that timeslicing works well. We test that elsewhere.
phasecentre = SkyCoord(ra=+180.0 * u.deg, dec=-60.0 * u.deg, frame='icrs', equinox='J2000')
vt = create_blockvisibility(lowcore, times, frequency, channel_bandwidth=channel_bandwidth,
weight=1.0, phasecentre=phasecentre,
polarisation_frame=PolarisationFrame("stokesI"))
cellsize = 0.001
model = create_image_from_visibility(vt, npixel=self.npixel, cellsize=cellsize, npol=1,
frequency=reffrequency,
polarisation_frame=PolarisationFrame("stokesI"))
flux = numpy.array([[100.0]])
facets = 4
rpix = model.wcs.wcs.crpix - 1.0
spacing_pixels = self.npixel // facets
centers = [-1.5, -0.5, 0.5, 1.5]
comps = list()
for iy in centers:
for ix in centers:
p = int(round(rpix[0] + ix * spacing_pixels * numpy.sign(model.wcs.wcs.cdelt[0]))), \
int(round(rpix[1] + iy * spacing_pixels * numpy.sign(model.wcs.wcs.cdelt[1])))
sc = pixel_to_skycoord(p[0], p[1], model.wcs, origin=1)
comps.append(create_skycomponent(flux=flux, frequency=vt.frequency, direction=sc,
polarisation_frame=PolarisationFrame("stokesI")))
predict_skycomponent_blockvisibility(vt, comps)
insert_skycomponent(model, comps)
self.actualmodel = copy_image(model)
export_image_to_fits(model, '%s/test_imaging_model.fits' % (self.results_dir))
if add_errors:
# These will be the same for all calls
numpy.random.seed(180555)
gt = create_gaintable_from_blockvisibility(vt)
gt = simulate_gaintable(gt, phase_error=1.0, amplitude_error=0.0)
vt = apply_gaintable(vt, gt)
return vt
def test_predict_sky_components_coalesce(self):
sc = create_low_test_skycomponents_from_gleam(
flux_limit=10.0,
polarisation_frame=PolarisationFrame("stokesI"),
frequency=self.frequency,
kind='cubic',
phasecentre=SkyCoord("17h20m31s", "-00d58m45s"),
radius=0.1)
self.config = create_named_configuration('LOWBD2-CORE')
self.phasecentre = SkyCoord("17h20m31s", "-00d58m45s")
sampling_time = 3.76
self.times = numpy.arange(0.0, +300 * sampling_time, sampling_time)
self.vis = create_blockvisibility(
self.config,
self.times,
self.frequency,
phasecentre=self.phasecentre,
weight=1.0,
polarisation_frame=PolarisationFrame('stokesI'),
channel_bandwidth=self.channel_bandwidth)
self.vis = predict_skycomponent_blockvisibility(self.vis, sc)
cvt = coalesce_visibility(self.vis, time_coal=1.0)
assert cvt.cindex is not None
def actualSetup(self, sky_pol_frame='stokesIQUV', data_pol_frame='linear'):
self.lowcore = create_named_configuration('LOWBD2-CORE')
self.times = (numpy.pi / 43200.0) * numpy.arange(0.0, 300.0, 30.0)
vnchan = 3
self.frequency = numpy.linspace(1.0e8, 1.1e8, vnchan)
self.channel_bandwidth = numpy.array(
vnchan * [self.frequency[1] - self.frequency[0]])
# Define the component and give it some spectral behaviour
f = numpy.array([100.0, 20.0, -10.0, 1.0])
self.flux = numpy.array([f, 0.8 * f, 0.6 * f])
self.phasecentre = SkyCoord(ra=+180.0 * u.deg,
dec=-35.0 * u.deg,
frame='icrs',
equinox='J2000')
self.compabsdirection = SkyCoord(ra=+181.0 * u.deg,
dec=-35.0 * u.deg,
frame='icrs',
equinox='J2000')
if sky_pol_frame == 'stokesI':
self.flux = self.flux[:, 0][:, numpy.newaxis]
self.comp = Skycomponent(
direction=self.compabsdirection,
frequency=self.frequency,
flux=self.flux,
polarisation_frame=PolarisationFrame(sky_pol_frame))
self.vis = create_blockvisibility(
self.lowcore,
self.times,
self.frequency,
phasecentre=self.phasecentre,
channel_bandwidth=self.channel_bandwidth,
weight=1.0,
polarisation_frame=PolarisationFrame(data_pol_frame))
self.vis = predict_skycomponent_visibility(self.vis, self.comp)
def test_peel_skycomponent_blockvisibility(self):
df = 1e6
frequency = numpy.array([1e8 - df, 1e8, 1e8 + df])
channel_bandwidth = numpy.array([df, df, df])
# Define the component and give it some spectral behaviour
f = numpy.array([100.0, 20.0, -10.0, 1.0])
flux = numpy.array([f, 0.8 * f, 0.6 * f])
phasecentre = SkyCoord(0 * u.deg, -60.0 * u.deg)
config = create_named_configuration('LOWBD2-CORE')
peeldirection = SkyCoord(+15 * u.deg, -60.0 * u.deg)
times = numpy.linspace(-3.0, 3.0, 7) * numpy.pi / 12.0
# Make the visibility
vis = create_blockvisibility(
config,
times,
frequency,
phasecentre=phasecentre,
weight=1.0,
polarisation_frame=PolarisationFrame('linear'),
channel_bandwidth=channel_bandwidth)
vis.data['vis'][...] = 0.0
# First add in the source to be peeled.
peel = Skycomponent(direction=peeldirection,
frequency=frequency,
flux=flux,
polarisation_frame=PolarisationFrame("stokesIQUV"))
vis = predict_skycomponent_visibility(vis, peel)
# Make a gaintable and apply it to the visibility of the peeling source
gt = create_gaintable_from_blockvisibility(vis, timeslice='auto')
gt = simulate_gaintable(gt,
phase_error=0.01,
amplitude_error=0.01,
timeslice='auto')
gt.data['gain'] *= 0.3
vis = apply_gaintable(vis, gt, timeslice='auto')
# Now create a plausible field using the GLEAM sources
model = create_image_from_visibility(
vis,
cellsize=0.001,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesIQUV'))
bm = create_low_test_beam(model=model)
sc = create_low_test_skycomponents_from_gleam(
flux_limit=1.0,
polarisation_frame=PolarisationFrame("stokesIQUV"),
frequency=frequency,
kind='cubic',
phasecentre=phasecentre,
radius=0.1)
sc = apply_beam_to_skycomponent(sc, bm)
# Add in the visibility due to these sources
vis = predict_skycomponent_visibility(vis, sc)
assert numpy.max(numpy.abs(vis.vis)) > 0.0
# Now we can peel
vis, peel_gts = peel_skycomponent_blockvisibility(vis, peel)
assert len(peel_gts) == 1
residual = numpy.max(peel_gts[0].residual)
assert residual < 0.7, "Peak residual %.6f too large" % (residual)
im, sumwt = invert_timeslice(vis, model, timeslice='auto')
qa = qa_image(im)
assert numpy.abs(qa.data['max'] - 14.2) < 1.0, str(qa)
def actualSetup(self, sky_pol_frame='stokesI', data_pol_frame='stokesI', f=None, vnchan=1, doiso=True,
ntimes=1, flux_limit=18.0):
nfreqwin = vnchan
ntimes = ntimes
rmax = 300.0
npixel = 1024
cellsize = 0.001
frequency = numpy.linspace(0.8e8, 1.2e8, nfreqwin)
if nfreqwin > 1:
channel_bandwidth = numpy.array(nfreqwin * [frequency[1] - frequency[0]])
else:
channel_bandwidth = [0.4e8]
times = numpy.linspace(-numpy.pi / 3.0, numpy.pi / 3.0, ntimes)
phasecentre = SkyCoord(ra=+0.0 * u.deg, dec=-45.0 * u.deg, frame='icrs', equinox='J2000')
lowcore = create_named_configuration('LOWBD2', rmax=rmax)
block_vis = create_blockvisibility(lowcore, times, frequency=frequency, channel_bandwidth=channel_bandwidth,
weight=1.0, phasecentre=phasecentre,
polarisation_frame=PolarisationFrame("stokesI"))
block_vis.data['uvw'][..., 2] = 0.0
self.beam = create_image_from_visibility(block_vis, npixel=npixel, frequency=[numpy.average(frequency)],
nchan=nfreqwin,
channel_bandwidth=[numpy.sum(channel_bandwidth)], cellsize=cellsize,
phasecentre=phasecentre)
self.components = create_low_test_skycomponents_from_gleam(flux_limit=flux_limit, phasecentre=phasecentre,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesI'),
radius=npixel * cellsize)
self.beam = create_low_test_beam(self.beam)
self.components = apply_beam_to_skycomponent(self.components, self.beam, flux_limit=flux_limit / 100.0)
print("Number of components %d" % len(self.components))
self.vis = copy_visibility(block_vis, zero=True)
gt = create_gaintable_from_blockvisibility(block_vis, timeslice='auto')
for i, sc in enumerate(self.components):
if sc.flux[0, 0] > 10:
sc.flux[...] /= 10.0
print('Component %d, flux = %s' % (i, str(sc.flux[0, 0])))
component_vis = copy_visibility(block_vis, zero=True)
gt = simulate_gaintable(gt, amplitude_error=0.0, phase_error=0.1, seed=None)
component_vis = predict_skycomponent_visibility(component_vis, sc)
component_vis = apply_gaintable(component_vis, gt)
self.vis.data['vis'][...] += component_vis.data['vis'][...]
# Do an isoplanatic selfcal
self.model_vis = copy_visibility(self.vis, zero=True)
self.model_vis = predict_skycomponent_visibility(self.model_vis, self.components)
if doiso:
gt = solve_gaintable(self.vis, self.model_vis, phase_only=True, timeslice='auto')
self.vis = apply_gaintable(self.vis, gt, inverse=True)
self.model_vis = convert_blockvisibility_to_visibility(self.model_vis)
self.model_vis, _, _ = weight_visibility(self.model_vis, self.beam)
self.dirty_model, sumwt = invert_function(self.model_vis, self.beam, context='2d')
export_image_to_fits(self.dirty_model, "%s/test_sagecal-model_dirty.fits" % self.dir)
lvis = convert_blockvisibility_to_visibility(self.vis)
lvis, _, _ = weight_visibility(lvis, self.beam)
dirty, sumwt = invert_function(lvis, self.beam, context='2d')
print(qa_image(dirty))
export_image_to_fits(dirty, "%s/test_sagecal-initial_dirty.fits" % self.dir)
# We create a graph to make the visibility. The parameter rmax determines the distance of the furthest antenna/stations used. All over parameters are determined from this number.
nfreqwin=5
ntimes=11
rmax=300.0
frequency=numpy.linspace(0.8e8,1.2e8,nfreqwin)
channel_bandwidth=numpy.array(nfreqwin*[frequency[1]-frequency[0]])
times = numpy.linspace(-numpy.pi/3.0, numpy.pi/3.0, ntimes)
phasecentre=SkyCoord(ra=+30.0 * u.deg, dec=-60.0 * u.deg, frame='icrs', equinox='J2000')
lowcore = create_named_configuration('LOWBD2-CORE', rmax=rmax)
block_vis = create_blockvisibility(lowcore, times, frequency=frequency, channel_bandwidth=channel_bandwidth,
weight=1.0, phasecentre=phasecentre,
polarisation_frame=PolarisationFrame("stokesI"))
wprojection_planes=1
advice=advise_wide_field(block_vis, guard_band_image=4.0, delA=0.02,
wprojection_planes=wprojection_planes)
vis_slices = advice['vis_slices']
npixel=advice['npixels2']
cellsize=advice['cellsize']
gleam_model = create_low_test_image_from_gleam(npixel=npixel, frequency=frequency,
channel_bandwidth=channel_bandwidth, cellsize=cellsize, phasecentre=phasecentre, flux_limit = 1.0, applybeam=True)
