def simulate_gaintable(gt: GainTable, phase_error=0.1, amplitude_error=0.0, leakage=0.0) -> GainTable:
""" Simulate a gain table
:type gt: GainTable
:param phase_error: std of normal distribution, zero mean
:param amplitude_error: std of log normal distribution
:param leakage: std of cross hand leakage
"""
log.info("simulate_gaintable: Simulating amplitude error = %.4f, phase error = %.4f"
% (amplitude_error, phase_error))
amp = 1.0
phasor = 1.0
if phase_error:
phasor = numpy.exp(1j * numpy.random.normal(0, phase_error, gt.data['gain'].shape))
if amplitude_error > 0.0:
amp = numpy.random.lognormal(mean=0.0, sigma=amplitude_error, size=gt.data['gain'].shape)
gt.data['gain'] = amp * phasor
nrec = gt.data['gain'].shape[-1]
if nrec > 1:
if leakage > 0.0:
leak = numpy.random.normal(0, leakage, gt.data['gain'][..., 0, 0].shape) + 1j * \
numpy.random.normal(0, leakage, gt.data['gain'][..., 0, 0].shape)
gt.data['gain'][..., 0, 1] = gt.data['gain'][..., 0, 0] * leak
leak = numpy.random.normal(0, leakage, gt.data['gain'][..., 1, 1].shape) + 1j * \
numpy.random.normal(0, leakage, gt.data['gain'][..., 1, 1].shape)
gt.data['gain'][..., 1, 0] = gt.data['gain'][..., 1, 1] * leak
else:
gt.data['gain'][..., 0, 1] = 0.0
gt.data['gain'][..., 1, 0] = 0.0
return gt
def create_gaintable_from_rows(gt: GainTable,
rows: numpy.ndarray,
makecopy=True) -> GainTable:
""" Create a GainTable from selected rows
:param gt: GainTable
:param rows: Boolean array of row selection
:param makecopy: Make a deep copy (True)
:return: GainTable
"""
if rows is None or numpy.sum(rows) == 0:
return None
assert len(
rows
) == gt.ntimes, "Length of rows does not agree with length of GainTable"
assert isinstance(gt, GainTable), gt
if makecopy:
newgt = copy_gaintable(gt)
newgt.data = copy.deepcopy(gt.data[rows])
return newgt
else:
gt.data = copy.deepcopy(gt.data[rows])
return gt
def test_create_gaintable_from_other(self):
for timeslice in [10.0, 'auto', 1e5]:
for spf, dpf in [('stokesIQUV', 'linear')]:
self.actualSetup(spf, dpf)
gt = create_gaintable_from_blockvisibility(self.vis,
timeslice=timeslice)
log.info("Created gain table: %s" % (gaintable_summary(gt)))
new_gt = GainTable(data=gt.data)
assert new_gt.data.shape == gt.data.shape
def append_gaintable(gt: GainTable, othergt: GainTable) -> GainTable:
"""Append othergt to gt
:param gt:
:param othergt:
:return: GainTable gt + othergt
"""
assert gt.receptor_frame == othergt.receptor_frame
gt.data = numpy.hstack((gt.data, othergt.data))
return gt
def create_gaintable_from_blockvisibility(vis: BlockVisibility,
time_width: float = None,
frequency_width: float = None,
**kwargs) -> GainTable:
""" Create gain table from visibility.
This makes an empty gain table consistent with the BlockVisibility.
:param vis: BlockVisibilty
:param time_width: Time interval between solutions (s)
:param frequency_width: Frequency solution width (Hz)
:return: GainTable
"""
assert isinstance(
vis, BlockVisibility), "vis is not a BlockVisibility: %r" % vis
nants = vis.nants
utimes = numpy.unique(vis.time)
ntimes = len(utimes)
ufrequency = numpy.unique(vis.frequency)
nfrequency = len(ufrequency)
receptor_frame = ReceptorFrame(vis.polarisation_frame.type)
nrec = receptor_frame.nrec
gainshape = [ntimes, nants, nfrequency, nrec, nrec]
gain = numpy.ones(gainshape, dtype='complex')
if nrec > 1:
gain[..., 0, 1] = 0.0
gain[..., 1, 0] = 0.0
gain_weight = numpy.ones(gainshape)
gain_time = utimes
gain_frequency = ufrequency
gain_residual = numpy.zeros([ntimes, nfrequency, nrec, nrec])
gt = GainTable(gain=gain,
time=gain_time,
weight=gain_weight,
residual=gain_residual,
frequency=gain_frequency,
receptor_frame=receptor_frame)
assert isinstance(gt, GainTable), "gt is not a GainTable: %r" % gt
assert_vis_gt_compatible(vis, gt)
return gt
def create_gaintable_from_blockvisibility(vis: BlockVisibility,
timeslice: float = None,
frequencyslice: float = None,
**kwargs) -> GainTable:
""" Create gain table from visibility.
This makes an empty gain table consistent with the BlockVisibility.
:param vis: BlockVisibilty
:param timeslice: Time interval between solutions (s)
:param frequency_width: Frequency solution width (Hz)
:return: GainTable
"""
assert isinstance(
vis, BlockVisibility), "vis is not a BlockVisibility: %r" % vis
nants = vis.nants
if timeslice is None or timeslice == 'auto':
utimes = numpy.unique(vis.time)
ntimes = len(utimes)
gain_interval = numpy.zeros([ntimes])
if ntimes > 1:
gain_interval[:-1] = utimes[1:] - utimes[0:-1]
gain_interval[-1] = utimes[-1] - utimes[-2]
else:
gain_interval[...] = 1.0
else:
ntimes = numpy.ceil((numpy.max(vis.time) - numpy.min(vis.time)) /
timeslice).astype('int')
utimes = numpy.linspace(numpy.min(vis.time), numpy.max(vis.time),
ntimes)
gain_interval = timeslice * numpy.ones([ntimes])
log.debug('create_gaintable_from_blockvisibility: times are %s' %
str(utimes))
log.debug('create_gaintable_from_blockvisibility: intervals are %s' %
str(gain_interval))
ntimes = len(utimes)
ufrequency = numpy.unique(vis.frequency)
nfrequency = len(ufrequency)
receptor_frame = ReceptorFrame(vis.polarisation_frame.type)
nrec = receptor_frame.nrec
gainshape = [ntimes, nants, nfrequency, nrec, nrec]
gain = numpy.ones(gainshape, dtype='complex')
if nrec > 1:
gain[..., 0, 1] = 0.0
gain[..., 1, 0] = 0.0
gain_weight = numpy.ones(gainshape)
gain_time = utimes
gain_frequency = ufrequency
gain_residual = numpy.zeros([ntimes, nfrequency, nrec, nrec])
gt = GainTable(gain=gain,
time=gain_time,
interval=gain_interval,
weight=gain_weight,
residual=gain_residual,
frequency=gain_frequency,
receptor_frame=receptor_frame)
assert isinstance(gt, GainTable), "gt is not a GainTable: %r" % gt
assert_vis_gt_compatible(vis, gt)
return gt
def gaintable_summary(gt: GainTable):
"""Return string summarizing the Gaintable
"""
return "%s rows, %.3f GB" % (gt.data.shape, gt.size())
def simulate_gaintable(gt: GainTable,
phase_error=0.1,
amplitude_error=0.0,
smooth_channels=1,
leakage=0.0,
seed=180555,
**kwargs) -> GainTable:
""" Simulate a gain table
:type gt: GainTable
:param phase_error: std of normal distribution, zero mean
:param amplitude_error: std of log normal distribution
:param leakage: std of cross hand leakage
:param seed: Seed for random numbers def: 180555
:param smooth_channels: Use bspline over smooth_channels
:param kwargs:
:return: Gaintable
"""
def moving_average(a, n=3):
return numpy.convolve(a, numpy.ones((n, )) / n, mode='valid')
numpy.random.seed(seed)
log.debug(
"simulate_gaintable: Simulating amplitude error = %.4f, phase error = %.4f"
% (amplitude_error, phase_error))
amps = 1.0
phases = 1.0
ntimes, nant, nchan, nrec, _ = gt.data['gain'].shape
if phase_error > 0.0:
phases = numpy.zeros(gt.data['gain'].shape)
for time in range(ntimes):
for ant in range(nant):
phase = numpy.random.normal(0, phase_error,
nchan + int(smooth_channels) - 1)
if smooth_channels > 1:
phase = moving_average(phase, smooth_channels)
phases[time, ant, ...] = phase[..., numpy.newaxis,
numpy.newaxis]
if amplitude_error > 0.0:
amps = numpy.ones(gt.data['gain'].shape, dtype='complex')
for time in range(ntimes):
for ant in range(nant):
amp = numpy.random.lognormal(mean=0.0,
sigma=amplitude_error,
size=nchan +
int(smooth_channels) - 1)
if smooth_channels > 1:
amp = moving_average(amp, smooth_channels)
amp = amp / numpy.average(amp)
amps[time, ant, ...] = amp[..., numpy.newaxis, numpy.newaxis]
gt.data['gain'] = amps * numpy.exp(0 + 1j * phases)
nrec = gt.data['gain'].shape[-1]
if nrec > 1:
if leakage > 0.0:
leak = numpy.random.normal(0, leakage, gt.data['gain'][..., 0, 0].shape) + 1j * \
numpy.random.normal(0, leakage, gt.data['gain'][..., 0, 0].shape)
gt.data['gain'][..., 0, 1] = gt.data['gain'][..., 0, 0] * leak
leak = numpy.random.normal(0, leakage, gt.data['gain'][..., 1, 1].shape) + 1j * \
numpy.random.normal(0, leakage, gt.data['gain'][..., 1, 1].shape)
gt.data['gain'][..., 1, 0] = gt.data['gain'][..., 1, 1] * leak
else:
gt.data['gain'][..., 0, 1] = 0.0
gt.data['gain'][..., 1, 0] = 0.0
return gt
