def BasebandProcess(ar_data, band, SR, dt, N, DN, offset, i, dd_coh, ngate):
print('ar_data', ar_data)
fh = mark4.open(ar_data,
'rs',
ntrack=64,
decade=2010,
sample_rate=SR,
thread_ids=[2 * band, 2 * band + 1])
fh.seek(offset + i * (N - DN))
t0 = fh.tell(unit='time')
print('t0', t0)
t1 = t0.mjd
print('t1', t1)
print('N-DN', N - DN)
print('dt', dt)
print('ngate', ngate)
# note ph is equilibrium to ((ph)*P0) / (P0/ngate) % ngate
ph, ncycle = FindPhase(t0, N - DN, dt, ngate)
ph %= ngate
print('ph3', ph)
z = fh.read(N)
z = rfft(z, axis=0, **_fftargs)
z *= dd_coh[..., np.newaxis]
z = irfft(z, axis=0, **_fftargs)[:-DN]
z = z.astype(np.float32)
z = z * z
return ph, z
def FindOffset(ar_data, SR):
from astropy.time import Time
fh = mark4.open(ar_data, 'rs', ntrack=64, decade=2010, sample_rate=SR)
t0 = fh.time0
offset_time = Time(math.ceil(t0.unix), format='unix', precision=9)
offset = fh.seek(offset_time)
t00 = np.float128(offset_time.mjd) # previous: isot
print('offset', offset)
print('t00', t00)
return offset, t00
def open(self, fname):
"""Open data with appropriate baseband reader"""
if self.dtype == 'vdif':
self.fh = vdif.open(fname, mode='rs', sample_rate=self.sample_rate)
if self.dtype == 'mark4':
self.fh = mark4.open(fname, mode='rs', decade=2010, ntrack=self.ntrack,
sample_rate=self.sample_rate, thread_ids=self.thread_ids)
if self.dtype == 'mark5b':
self.fh = mark5b.open(fname, mode='rs', nchan=self.nIF, ref_mjd=57000,
sample_rate=self.sample_rate, thread_ids=self.thread_ids)
def open(self, fname):
"""Open data with appropriate baseband reader"""
if self.dtype == 'vdif':
self.fh = vdif.open(fname, mode='rs', sample_rate=self.sample_rate)
if self.dtype == 'mark4':
self.fh = mark4.open(fname,
mode='rs',
decade=2010,
ntrack=self.ntrack,
sample_rate=self.sample_rate,
thread_ids=self.thread_ids)
if self.dtype == 'mark5b':
self.fh = mark5b.open(fname,
mode='rs',
nchan=self.nIF,
ref_mjd=57000,
sample_rate=self.sample_rate,
thread_ids=self.thread_ids)
dang = (d * f * (1./fref-1./f)**2) * u.cycle
if kind == 'phase':
return dang
elif kind == 'complex':
return np.exp(dang.to(u.rad).value * 1j)
raise ValueError("kind not one of 'delay', 'phase', or 'complex'")
print("Pre-Calculating De-Dispersion Phases")
dm = DispersionMeasure(dm)
dd = dm(f, fref, kind='complex').conj()
if __name__ == '__main__':
print('Reading...')
fh = mark4.open(fn, mode='rs', decade=2010, ntrack=64,
sample_rate=sample_rate, thread_ids=thread_ids)
offset_gp = ((t_gp - fh.tell(unit='time')).to(u.s).value *
fh.frames_per_second * fh.samples_per_frame)
fh.seek(int(offset_gp) - size // 2)
d = pyfftw.empty_aligned((2**25,6), dtype='float32')
d[:] = fh.read(size)
print('First FFT')
ft = fft_object_a(d)
print('De-Dispersing')
ft *= dd
print('Second FFT')
d = pyfftw.empty_aligned((2**24+1,6), dtype='complex64')
d[:] = ft
data = fft_object_b(d)
plt.ion()
fdir = '/scratch/p/pen/simardda/B1133/gk049c/ar/'
fname = sys.argv[1]
output_name = fname[:-4]
# Load Data
frequency = np.array([[320.25], [320.25], [336.25], [336.25]]) * u.MHz
sideband = np.array([[-1, -1], [1, 1], [-1, -1], [1, 1]])
polarization = ['R', 'L']
dispersion_measure = 4.84066 * u.pc / u.cm**3
polyco_file = 'B1133_ar_polycopolyco_new.dat'
fullpol = False
print("Parameters set")
# Creating stream reader. For other formats, such as vdif, use vdif.open(...)
fh = mark4.open(fdir + fname, 'rs', decade=2010)
rh = Reshape(fh, (4, 2))
dt = TimeDelta(10, format='sec')
# Rounding Time
start = Time(rh.time)
start_time_str = start.iso.__str__()
new_time = Time(start_time_str, precision = -1)
new_time_str = new_time.iso.__str__()
start_time = Time(new_time_str) + dt
print("Opened stream reader with sample shape:", rh.sample_shape)
print("Starting at time:", start_time)
# Initial waterfall interpretor
WF = sr.Fold(rh, dispersion_measure, frequency, sideband, polyco_file, polarization, fullpol,start=start_time, nthreads=1)
return d * (1./f**2 - 1./fref**2)
else:
dang = (d * f * (1./fref-1./f)**2) * u.cycle
if kind == 'phase':
return dang
elif kind == 'complex':
return np.exp(dang.to(u.rad).value * 1j)
raise ValueError("kind not one of 'delay', 'phase', or 'complex'")
dm = DispersionMeasure(dm)
if __name__ == '__main__':
fh = mark4.open(fn, mode='rs', decade=2010, ntrack=64,
sample_rate=sample_rate, thread_ids=thread_ids)
# Compute offset to have giant pulse in middle of data chunk
offset_gp = ((t_gp - fh.tell(unit='time')).to(u.s).value *
fh.frames_per_second * fh.samples_per_frame)
# Go to that offset, read "size" number of samples
fh.seek(int(offset_gp) - size // 2)
d = fh.read(size)
# For coherent de-dispersion, FT to frequency space
# apply de-dispersion delay as phase rotation
ft = np.fft.rfft(d, axis=0)
f = fedge + np.fft.rfftfreq(d.shape[0], dt1)[:, np.newaxis]
ft *= dm(f, fref, kind='complex').conj()
d = np.fft.irfft(ft, axis=0)