def from_fil(filename):
""" Create a DataArray from a sigproc filterbank file
Args:
filename (str): Path to filterbank file.
Returns a DataArray object with mem-mapped filterbank data.
"""
# Filterbank reading
from blimpy.io import sigproc
hdr = sigproc.read_header(filename)
hdrlen = sigproc.len_header(filename)
n_int = sigproc.calc_n_ints_in_file(filename)
shape = (n_int, hdr['nbeams'], hdr['nchans'])
data = np.memmap(filename=filename, dtype='float32', offset=hdrlen, shape=shape)
attrs = {'name': os.path.basename(filename),
'source': hdr['source_name'],
'sky_coord': SkyCoord(hdr['src_raj'], hdr['src_dej'])}
dims = ('time', 'feed_id', 'frequency')
scales = {
'time': TimeScale('time', hdr['tstart'], hdr['tsamp'], data.shape[0], time_format='mjd', time_delta_format='sec'),
'feed_id': DimensionScale('feed_id', 0, 0, data.shape[1], units=''),
'frequency': DimensionScale('frequency', hdr['fch1'], hdr['foff'], data.shape[2], units='MHz')
}
d = DataArray(data, dims, scales, attrs)
return d
def _setup_n_ints_in_file(self):
""" Calculate the number of integrations in the file. """
self.n_ints_in_file = sigproc.calc_n_ints_in_file(self.filename)