Read utilties for CHIME/FRB Open Data Release.
pip install cfod
Note: Currently only Python 2.7 is supported.
To read a single data file from the data release,
from cfod import chime_intensity as ci
fn = `astro_5941664_20180406203904337770_beam0147_00245439_02.msgpack`
intensity, weights, fpga0, fpgaN, binning, frame0_nano, nrfifreq, rfi_mask = ci.unpack_data(fn)where:
intensityis a 2D Intensity array.weightsare the corresponding 2D array weights to the intensity array.fpga0 (int)is start fpga count of the data chunk. (Internally used to track time, can be ignored). The fpga count increments at the rate of 2.56us.fpgaN (int)is number of fpga counts in the data chunk readbinning (int)is the downsampling of the data from the ringbufferframe0_nanois the conversion from fpga timestamp to utc timestamp (Currently not supported.)nrfifreqis the number of frequences masked by the realtime rfi system (Currently not supported.)rfi_maskis currently not supported
To read multiple data files at once, you can use the following command,
from cfod import chime_intensity as ci
fns = ['file1', 'file2', 'file3']
intensity, weights, fpga0s, fpgaNs, binning, rfi_mask, frame0_nanos = ci.unpack_datafiles(fns)To convert .msgpack files into filterbank .fil format you can run msgpack2fil from the command line (scripts are installed through pip). You need to provide a pathname wildcard in quotation marks. To see all command line options run help:
msgpack2fil --help
CHIME/FRB data has 16384 frequency channels but PRESTO and sigproc by default allocate memory for only a maximum of 4096 channels. You would need to update reader.h and header.h in sigproc and recompile before trying to read a 16384 filterbank file, or you can let msgpack2fil subband data by at least a factor 4 (using the --fscrunch argument). Make sure to provide a DM for subband dedispersion (using the --subdm argument) to mitigate subband smearing.
pip uninstall cfod