def test_estimate_welch(self):
"""Test estimating PSDs from data using Welch's method"""
for seg_len in (2048, 4096, 8192):
noise_model = (numpy.linspace(1., 100., seg_len/2 + 1)) ** (-2)
for seg_stride in (seg_len, seg_len/2):
for method in ('mean', 'median', 'median-mean'):
with self.context:
psd = pycbc.psd.welch(self.noise, seg_len=seg_len, \
seg_stride=seg_stride, avg_method=method)
error = (psd.numpy() - noise_model) / noise_model
err_rms = numpy.sqrt(numpy.mean(error ** 2))
self.assertTrue(err_rms < 0.2,
msg='seg_len=%d seg_stride=%d method=%s -> rms=%.3f' % \
(seg_len, seg_stride, method, err_rms))
def test_estimate_welch(self):
"""Test estimating PSDs from data using Welch's method"""
for seg_len in (2048, 4096, 8192):
noise_model = (numpy.linspace(1., 100., seg_len // 2 + 1))**(-2)
for seg_stride in (seg_len, seg_len // 2):
for method in ('mean', 'median', 'median-mean'):
with self.context:
psd = pycbc.psd.welch(self.noise, seg_len=seg_len, \
seg_stride=seg_stride, avg_method=method)
error = (psd.numpy() - noise_model) / noise_model
err_rms = numpy.sqrt(numpy.mean(error**2))
self.assertTrue(err_rms < 0.2,
msg='seg_len=%d seg_stride=%d method=%s -> rms=%.3f' % \
(seg_len, seg_stride, method, err_rms))
def trigger_list_from_map(tfmap, event_list, threshold, start_time, start_freq, duration, band, df, dt, psd=None):
# FIXME: If we don't convert this the calculation takes forever ---
# but we should convert it once and handle deltaF better later
if psd is not None:
npy_psd = psd.numpy()
start_time = LIGOTimeGPS(float(start_time))
ndof = 2 * duration * band
for i, j in zip(*numpy.where(tfmap > threshold)):
event = event_list.RowType()
# The points are summed forward in time and thus a `summed point' is the
# sum of the previous N points. If this point is above threshold, it
# corresponds to a tile which spans the previous N points. However, the
# 0th point (due to the convolution specifier 'valid') is actually
# already a duration from the start time. All of this means, the +
# duration and the - duration cancels, and the tile 'start' is, by
# definition, the start of the time frequency map if j = 0
# FIXME: I think this needs a + dt/2 to center the tile properly
event.set_start(start_time + float(j * dt))
event.set_stop(start_time + float(j * dt) + duration)
event.set_peak(event.get_start() + duration / 2)
event.central_freq = start_freq + i * df + 0.5 * band
event.duration = duration
event.bandwidth = band
event.chisq_dof = ndof
event.snr = math.sqrt(tfmap[i,j] / event.chisq_dof - 1)
# FIXME: Magic number 0.62 should be determine empircally
event.confidence = -lal.LogChisqCCDF(event.snr * 0.62, event.chisq_dof * 0.62)
if psd is not None:
# NOTE: I think the pycbc PSDs always start at 0 Hz --- check
psd_idx_min = int((event.central_freq - event.bandwidth / 2) / psd.delta_f)
psd_idx_max = int((event.central_freq + event.bandwidth / 2) / psd.delta_f)
# FIXME: heuristically this works better with E - D -- it's all
# going away with the better h_rss calculation soon anyway
event.amplitude = measure_hrss_poorly(tfmap[i,j] - event.chisq_dof, npy_psd[psd_idx_min:psd_idx_max])
else:
event.amplitude = None
event.process_id = None
event.event_id = event_list.get_next_id()
event_list.append(event)
def test_truncation(self):
"""Test inverse PSD truncation"""
for seg_len in (2048, 4096, 8192):
noise_model = (numpy.linspace(1., 100., seg_len/2 + 1)) ** (-2)
for max_len in (1024, 512, 256):
with self.context:
psd = pycbc.psd.welch(self.noise, seg_len=seg_len, \
seg_stride=seg_len/2, avg_method='mean')
psd_trunc = pycbc.psd.inverse_spectrum_truncation(
psd, max_len,
low_frequency_cutoff=self.psd_low_freq_cutoff)
freq = psd.sample_frequencies.numpy()
error = (psd.numpy() - noise_model) / noise_model
error = error[freq > self.psd_low_freq_cutoff]
err_rms = numpy.sqrt(numpy.mean(error ** 2))
self.assertTrue(err_rms < 0.1,
msg='seg_len=%d max_len=%d -> rms=%.3f' \
% (seg_len, max_len, err_rms))
def test_truncation(self):
"""Test inverse PSD truncation"""
for seg_len in (2048, 4096, 8192):
noise_model = (numpy.linspace(1., 100., seg_len // 2 + 1))**(-2)
for max_len in (1024, 512, 256):
with self.context:
psd = pycbc.psd.welch(self.noise, seg_len=seg_len, \
seg_stride=seg_len//2, avg_method='mean')
psd_trunc = pycbc.psd.inverse_spectrum_truncation(
psd,
max_len,
low_frequency_cutoff=self.psd_low_freq_cutoff)
freq = psd.sample_frequencies.numpy()
error = (psd.numpy() - noise_model) / noise_model
error = error[freq > self.psd_low_freq_cutoff]
err_rms = numpy.sqrt(numpy.mean(error**2))
self.assertTrue(err_rms < 0.1,
msg='seg_len=%d max_len=%d -> rms=%.3f' \
% (seg_len, max_len, err_rms))
# List the available analytic psds
print(pycbc.psd.get_lalsim_psd_list())
delta_f = 1.0 / 4
flen = int(1024 / delta_f)
low_frequency_cutoff = 30.0
# PSD of detector
psd = pycbc.psd.aLIGOZeroDetHighPower(flen, delta_f, low_frequency_cutoff)
psd_1 = pycbc.psd.aLIGOZeroDetLowPower(flen, delta_f, low_frequency_cutoff)
psd_2 = pycbc.psd.eLIGOModel(flen, delta_f, low_frequency_cutoff)
psd_3 = pycbc.psd.iLIGOModel(flen, delta_f, low_frequency_cutoff)
# ASD of the PSD
asd = pycbc.types.frequencyseries.FrequencySeries(numpy.sqrt(psd.numpy()),
delta_f=psd.delta_f)
asd_1 = pycbc.types.frequencyseries.FrequencySeries(numpy.sqrt(psd_1.numpy()),
delta_f=psd_1.delta_f)
asd_2 = pycbc.types.frequencyseries.FrequencySeries(numpy.sqrt(psd_2.numpy()),
delta_f=psd_2.delta_f)
asd_3 = pycbc.types.frequencyseries.FrequencySeries(numpy.sqrt(psd_3.numpy()),
delta_f=psd_3.delta_f)
# Potting
fig = plt.figure()
ax = fig.add_subplot(1, 1, 1)
ax.loglog(asd.sample_frequencies,
asd,
linewidth=3,
label='aLIGO High Power Design')