mwax-db2fits

MWA Correlator (mwax): PSRDADA ringbuffer to FITS file converter

Dependencies

CFITSIO

• See https://heasarc.gsfc.nasa.gov/fitsio/fitsio.html

psrdada prerequisites

• pkg-config
• libhwloc-dev (this is to enable the use of NUMA awareness in psrdada)
• csh
• autoconf
• libtool

psrdada (http://psrdada.sourceforge.net/)

• download the source from the cvs repo (http://psrdada.sourceforge.net/current/)
• build (http://psrdada.sourceforge.net/current/build.shtml)

Building Release version

./build.sh

Running / Command line Arguments

Example from mwax_db2fits --help

mwax_db2fits v0.10.3

Usage: mwax_db2fits [OPTION]...

This code will open the dada ringbuffer containing raw
visibility data from the MWAX Correlator.
It will then write out a fits file to be picked up by the
archiver process.

  -k --key=KEY                      Hexadecimal shared memory key
  -d --destination-path=PATH        Destination path for gpubox files
  -n --health-netiface=INTERFACE    Health UDP network interface to send with
  -i --health-ip=IP                 Health UDP Multicast destination ip address
  -p --health-port=PORT             Health UDP Multicast destination port
  -l --file-size-limit=BYTES        FITS file size limit before splitting into a new file. Default=10737418240 bytes. 0=no splitting
  -v --version                      Display version number
  -? --help                         This help text

Testing an Debugging

Build the Debug Binary

./build_debug.sh

Run all tests

./run_tests.sh

Health Packet format

Every 1 second, a UDP health packet is sent to the health_ip and health_port via the health-netiface interface.

The payload is a packed C struct with the following format:

Type	Name	Example	Notes
int16	version_major	1	mwax_db2fits major version number
int16	version_minor	2	mwax_db2fits minor version number
int16	version_revision	3	mwax_db2fits revision number
char[64]	hostname	mwax01	hostanme of the server
time_t	start_time	1683779031	UNIX Time when program was started
time_t	health_time	1683780123	UNIX Time when health packet was assembled
float64	up_time	1092	Number of seconds alive
int16	status	1	0 = Offline, 1= Running, 2= shutting down
int32	obs_id	1234567890	obs_id GPS time or 0 if no current observation
int32	subobs_id	1234567890	sub_obs_id GPS time or 0 if no current observation
float32[256]	weights_per_tile_x	1.0,0.9,0.92,1.0...	Each element is tile 0..255 X pol weight. If ntiles is <256, unused tiles will have NaN. If no weights can be reported then the array will have 256 NaN elements. Tile order is MWAX order.
float32[256]	weights_per_tile_y	1.0,0.9,0.92,1.0...	Each element is tile 0..255 Y pol weight. If ntiles is <256, unused tiles will have NaN. If no weights can be reported then the array will have 256 NaN elements. Tile order is MWAX oder.