def partition_skymodel_by_flux(sc, model, flux_threshold=-numpy.inf):
"""Partition skymodel according to flux
Bright skycomponents are put into a SkyModel as a list, and weak skycomponents
are inserted into SkyModel as an image.
:param sc: List of skycomponents
:param model: Model image
:param flux_threshold:
:return: SkyModel
For example::
fluxes = numpy.linspace(0, 1.0, 11)
sc = [create_skycomponent(direction=phasecentre, flux=numpy.array([[f]]), frequency=frequency,
polarisation_frame=PolarisationFrame('stokesI')) for f in fluxes]
sm = partition_skymodel_by_flux(sc, model, flux_threshold=0.31)
assert len(sm.components) == 7, len(sm.components)
"""
brightsc = filter_skycomponents_by_flux(sc, flux_min=flux_threshold)
weaksc = filter_skycomponents_by_flux(sc, flux_max=flux_threshold)
log.info(
'Converted %d components into %d bright components and one image containing %d components'
% (len(sc), len(brightsc), len(weaksc)))
im = copy_image(model)
im = insert_skycomponent(im, weaksc)
return SkyModel(components=[copy_skycomponent(comp) for comp in brightsc],
image=copy_image(im),
mask=None,
fixed=False)
def copy_skymodel(sm):
""" Copy a sky model
:param sm: SkyModel to be copied
:return: SkyModel
"""
if sm.components is not None:
newcomps = [copy_skycomponent(comp) for comp in sm.components]
else:
newcomps = None
if sm.image is not None:
newimage = copy_image(sm.image)
else:
newimage = None
if sm.mask is not None:
newmask = copy_image(sm.mask)
else:
newmask = None
if sm.gaintable is not None:
newgt = copy_gaintable(sm.gaintable)
else:
newgt = None
return SkyModel(components=newcomps,
image=newimage,
gaintable=newgt,
mask=newmask,
fixed=sm.fixed)
def partition_skymodel_by_flux(sc, model, flux_threshold=-numpy.inf):
"""Partition skymodel according to flux
:param sc:
:param model:
:param flux_threshold:
:return:
"""
brightsc = filter_skycomponents_by_flux(sc, flux_min=flux_threshold)
weaksc = filter_skycomponents_by_flux(sc, flux_max=flux_threshold)
log.info(
'Converted %d components into %d bright components and one image containing %d components'
% (len(sc), len(brightsc), len(weaksc)))
im = copy_image(model)
im = insert_skycomponent(im, weaksc)
return SkyModel(components=[copy_skycomponent(comp) for comp in brightsc],
image=copy_image(im),
mask=None,
fixed=False)
def create_simulation_components(context,
phasecentre,
frequency,
pbtype,
offset_dir,
flux_limit,
pbradius,
pb_npixel,
pb_cellsize,
show=False):
""" Construct components for simulation
:param context:
:param phasecentre:
:param frequency:
:param pbtype:
:param offset_dir:
:param flux_limit:
:param pbradius:
:param pb_npixel:
:param pb_cellsize:
:return:
"""
HWHM_deg, null_az_deg, null_el_deg = find_pb_width_null(pbtype, frequency)
dec = phasecentre.dec.deg
ra = phasecentre.ra.deg
if context == 'singlesource':
log.info("create_simulation_components: Constructing single component")
offset = [HWHM_deg * offset_dir[0], HWHM_deg * offset_dir[1]]
log.info(
"create_simulation_components: Offset from pointing centre = %.3f, %.3f deg"
% (offset[0], offset[1]))
# The point source is offset to approximately the halfpower point
offset_direction = SkyCoord(
ra=(ra + offset[0] / numpy.cos(numpy.pi * dec / 180.0)) *
units.deg,
dec=(dec + offset[1]) * units.deg,
frame='icrs',
equinox='J2000')
original_components = [
Skycomponent(flux=[[1.0]],
direction=offset_direction,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesI'))
]
elif context == 'null':
log.info(
"create_simulation_components: Constructing single component at the null"
)
offset = [null_az_deg * offset_dir[0], null_el_deg * offset_dir[1]]
HWHM = HWHM_deg * numpy.pi / 180.0
log.info(
"create_simulation_components: Offset from pointing centre = %.3f, %.3f deg"
% (offset[0], offset[1]))
# The point source is offset to approximately the null point
offset_direction = SkyCoord(
ra=(ra + offset[0] / numpy.cos(numpy.pi * dec / 180.0)) *
units.deg,
dec=(dec + offset[1]) * units.deg,
frame='icrs',
equinox='J2000')
original_components = [
Skycomponent(flux=[[1.0]],
direction=offset_direction,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesI'))
]
else:
offset = [0.0, 0.0]
# Make a skymodel from S3
max_flux = 0.0
total_flux = 0.0
log.info("create_simulation_components: Constructing s3sky components")
from rascil.processing_components.simulation import create_test_skycomponents_from_s3
original_components = create_test_skycomponents_from_s3(
flux_limit=flux_limit / 100.0,
phasecentre=phasecentre,
polarisation_frame=PolarisationFrame("stokesI"),
frequency=numpy.array(frequency),
radius=pbradius)
log.info(
"create_simulation_components: %d components before application of primary beam"
% (len(original_components)))
pbmodel = create_image(npixel=pb_npixel,
cellsize=pb_cellsize,
phasecentre=phasecentre,
frequency=frequency,
polarisation_frame=PolarisationFrame("stokesI"))
pb = create_pb(pbmodel,
"MID_GAUSS",
pointingcentre=phasecentre,
use_local=False)
pb_feko = create_pb(pbmodel,
pbtype,
pointingcentre=phasecentre,
use_local=True)
pb.data = pb_feko.data[:, 0, ...][:, numpy.newaxis, ...]
pb_applied_components = [
copy_skycomponent(c) for c in original_components
]
pb_applied_components = apply_beam_to_skycomponent(
pb_applied_components, pb)
filtered_components = []
for icomp, comp in enumerate(pb_applied_components):
if comp.flux[0, 0] > flux_limit:
total_flux += comp.flux[0, 0]
if abs(comp.flux[0, 0]) > max_flux:
max_flux = abs(comp.flux[0, 0])
filtered_components.append(original_components[icomp])
log.info(
"create_simulation_components: %d components > %.3f Jy after application of primary beam"
% (len(filtered_components), flux_limit))
log.info(
"create_simulation_components: Strongest components is %g (Jy)" %
max_flux)
log.info(
"create_simulation_components: Total flux in components is %g (Jy)"
% total_flux)
original_components = [
copy_skycomponent(c) for c in filtered_components
]
if show:
plt.clf()
show_image(pb, components=original_components)
plt.show(block=False)
log.info("create_simulation_components: Created %d components" %
len(original_components))
# Primary beam points to the phasecentre
offset_direction = SkyCoord(ra=ra * units.deg,
dec=dec * units.deg,
frame='icrs',
equinox='J2000')
return original_components, offset_direction
vis_list0,
npixel=pb_npixel,
cellsize=pb_cellsize,
override_cellsize=False,
phasecentre=phasecentre,
frequency=frequency,
nchan=nfreqwin,
polarisation_frame=PolarisationFrame("stokesI"))
pbmodel = rsexecute.compute(pbmodel, sync=True)
# Use MID_GAUSS to filter the components since MID_GRASP is in local coordinates
pb = create_pb(pbmodel,
"MID_GAUSS",
pointingcentre=phasecentre,
use_local=False)
pb_applied_components = [
copy_skycomponent(c) for c in original_components
]
pb_applied_components = apply_beam_to_skycomponent(
pb_applied_components, pb)
filtered_components = []
for icomp, comp in enumerate(pb_applied_components):
if comp.flux[0, 0] > flux_limit:
total_flux += comp.flux[0, 0]
if abs(comp.flux[0, 0]) > max_flux:
max_flux = abs(comp.flux[0, 0])
filtered_components.append(original_components[icomp])
print("%d components > %.3f Jy after application of primary beam" %
(len(filtered_components), flux_limit))
print("Strongest components is %g (Jy)" % max_flux)
print("Total flux in components is %g (Jy)" % total_flux)
original_components = [
def create_simulation_components(
context,
phasecentre,
frequency,
pbtype,
offset_dir,
flux_limit,
pbradius,
pb_npixel,
pb_cellsize,
show=False,
fov=10,
polarisation_frame=PolarisationFrame("stokesI"),
filter_by_primary_beam=True,
flux_max=10.0):
""" Construct components for simulation
:param context: singlesource or null or s3sky
:param phasecentre: Centre of components
:param frequency: Frequency
:param pbtype: Type of primary beam
:param offset_dir: Offset in ra, dec degrees
:param flux_limit: Lower limit flux
:param pbradius: Radius of components in radians
:param pb_npixel: Number of pixels in the primary beam model
:param pb_cellsize: Cellsize in primary beam model
:param fov: FOV in degrees (used to select catalog)
:param flux_max: Maximum flux in model before application of primary beam
:param filter_by_primary_beam: Filter components by primary beam
:param polarisation_frame:
:param show:
:return:
"""
HWHM_deg, null_az_deg, null_el_deg = find_pb_width_null(pbtype, frequency)
dec = phasecentre.dec.deg
ra = phasecentre.ra.deg
if context == 'singlesource':
log.info("create_simulation_components: Constructing single component")
offset = [HWHM_deg * offset_dir[0], HWHM_deg * offset_dir[1]]
log.info(
"create_simulation_components: Offset from pointing centre = %.3f, %.3f deg"
% (offset[0], offset[1]))
# The point source is offset to approximately the halfpower point
odirection = SkyCoord(
ra=(ra + offset[0] / numpy.cos(numpy.pi * dec / 180.0)) *
units.deg,
dec=(dec + offset[1]) * units.deg,
frame='icrs',
equinox='J2000')
if polarisation_frame.type == "stokesIQUV":
original_components = [
Skycomponent(
flux=[[1.0, 0.0, 0.0, 0.0]],
direction=odirection,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesIQUV'))
]
else:
original_components = [
Skycomponent(flux=[[1.0]],
direction=odirection,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesI'))
]
offset_direction = odirection
elif context == 'doublesource':
original_components = []
log.info(
"create_simulation_components: Constructing double components")
for sign_offset in [(-1, 0), (1, 0)]:
offset = [HWHM_deg * sign_offset[0], HWHM_deg * sign_offset[1]]
log.info(
"create_simulation_components: Offset from pointing centre = %.3f, %.3f deg"
% (offset[0], offset[1]))
odirection = SkyCoord(
ra=(ra + offset[0] / numpy.cos(numpy.pi * dec / 180.0)) *
units.deg,
dec=(dec + offset[1]) * units.deg,
frame='icrs',
equinox='J2000')
if polarisation_frame.type == "stokesIQUV":
original_components.append(
Skycomponent(
flux=[[1.0, 0.0, 0.0, 0.0]],
direction=odirection,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesIQUV')))
else:
original_components.append(
Skycomponent(
flux=[[1.0]],
direction=odirection,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesI')))
for o in original_components:
print(o)
offset_direction = odirection
elif context == 'null':
log.info(
"create_simulation_components: Constructing single component at the null"
)
offset = [null_az_deg * offset_dir[0], null_el_deg * offset_dir[1]]
HWHM = HWHM_deg * numpy.pi / 180.0
log.info(
"create_simulation_components: Offset from pointing centre = %.3f, %.3f deg"
% (offset[0], offset[1]))
# The point source is offset to approximately the null point
offset_direction = SkyCoord(
ra=(ra + offset[0] / numpy.cos(numpy.pi * dec / 180.0)) *
units.deg,
dec=(dec + offset[1]) * units.deg,
frame='icrs',
equinox='J2000')
if polarisation_frame.type == "stokesIQUV":
original_components = [
Skycomponent(
flux=[[1.0, 0.0, 0.0, 0.0]],
direction=offset_direction,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesIQUV'))
]
else:
original_components = [
Skycomponent(flux=[[1.0]],
direction=offset_direction,
frequency=frequency,
polarisation_frame=PolarisationFrame('stokesI'))
]
else:
offset = [0.0, 0.0]
# Make a skymodel from S3
max_flux = 0.0
total_flux = 0.0
log.info("create_simulation_components: Constructing s3sky components")
from rascil.processing_components.simulation import create_test_skycomponents_from_s3
all_components = create_test_skycomponents_from_s3(
flux_limit=flux_limit / 100.0,
phasecentre=phasecentre,
polarisation_frame=polarisation_frame,
frequency=numpy.array(frequency),
radius=pbradius,
fov=fov)
original_components = filter_skycomponents_by_flux(all_components,
flux_max=flux_max)
log.info(
"create_simulation_components: %d components before application of primary beam"
% (len(original_components)))
if filter_by_primary_beam:
pbmodel = create_image(
npixel=pb_npixel,
cellsize=pb_cellsize,
phasecentre=phasecentre,
frequency=frequency,
polarisation_frame=PolarisationFrame("stokesI"))
stokesi_components = [
copy_skycomponent(o) for o in original_components
]
for s in stokesi_components:
s.flux = numpy.array([[s.flux[0, 0]]])
s.polarisation_frame = PolarisationFrame("stokesI")
pb = create_pb(pbmodel,
"MID_GAUSS",
pointingcentre=phasecentre,
use_local=False)
pb_applied_components = [
copy_skycomponent(c) for c in stokesi_components
]
pb_applied_components = apply_beam_to_skycomponent(
pb_applied_components, pb)
filtered_components = []
for icomp, comp in enumerate(pb_applied_components):
if comp.flux[0, 0] > flux_limit:
total_flux += comp.flux[0, 0]
if abs(comp.flux[0, 0]) > max_flux:
max_flux = abs(comp.flux[0, 0])
filtered_components.append(original_components[icomp])
log.info(
"create_simulation_components: %d components > %.3f Jy after filtering with primary beam"
% (len(filtered_components), flux_limit))
log.info(
"create_simulation_components: Strongest components is %g (Jy)"
% max_flux)
log.info(
"create_simulation_components: Total flux in components is %g (Jy)"
% total_flux)
original_components = [
copy_skycomponent(c) for c in filtered_components
]
if show:
plt.clf()
show_image(pb, components=original_components)
plt.show(block=False)
log.info("create_simulation_components: Created %d components" %
len(original_components))
# Primary beam points to the phasecentre
offset_direction = SkyCoord(ra=ra * units.deg,
dec=dec * units.deg,
frame='icrs',
equinox='J2000')
return original_components, offset_direction