PSI simulations

These are simulated visibility data sets in Measurement Set format, as needed to test the operation of the CBF-SDP interface and the real-time signal displays.

These simulations generate fully time-sampled, high number of spectral channel observations using the simulated Prototype System Integration (PSI) test arrays: a small number of antennas or stations (between 4 and 8), with a large number of frequency channels (of order 10000).

The simulation currently does:

• 10 minutes of 0.28s integrations

• six antennas chosen to be close to the centre but to give baselines upto 200m

• 50% fractional bandwidth: centre frequency 1.369GHz +/- 0.5 * 1.369GHz

The simulation requires a large amount of memory, primality because of inefficiencies in the RASCIL visibility format. We expect to reduce these over time. The best Dask setup on Alaska P3 is to use one worker and a large number of threads (up to 64).

Simulate time and frequency dense PSI observations

usage: mid_write_psi.py [-h] [--rmax RMAX] [--configuration CONFIGURATION]
                        [--antennas [ANTENNAS [ANTENNAS ...]]]
                        [--badantenna BADANTENNA] [--howbad HOWBAD] [--ra RA]
                        [--declination DECLINATION] [--band BAND]
                        [--nchan NCHAN] [--nspw NSPW]
                        [--channel_width CHANNEL_WIDTH]
                        [--integration_time INTEGRATION_TIME]
                        [--time_range TIME_RANGE TIME_RANGE]
                        [--image_pol IMAGE_POL] [--vis_pol VIS_POL]
                        [--duration DURATION] [--results RESULTS]
                        [--msname MSNAME] [--split SPLIT]
                        [--nthreads NTHREADS] [--processes PROCESSES]
                        [--memory MEMORY] [--nworkers NWORKERS]
                        [--use_dask USE_DASK] [--interface INTERFACE]

Named Arguments

--rmax

Maximum distance of dish from centre (m)

Default: 200.0

--configuration

MID Configuration: MID | MEERKAT+

Default: “MID”

--antennas

antenna names to include (default is all)

--badantenna

Bad antenna

Default: -1

--howbad

How many meters to move bad antenna

Default: 1

--ra

Right ascension of phase centre (degrees)

Default: 0.0

--declination

Declination of phase centre (degrees)

Default: -55.0

--band

Band B1LOW | B1 | B2 | Ku

Default: “B2”

--nchan

Number of frequency channels

Default: 1024

--nspw

Number of spectral windows

Default: 8

--channel_width

Channel bandwidth (Hz) (default is to calculate from frequency

--integration_time

Integration time (s)

Default: 0.14

--time_range

Time range in hour angle

Default: [0, 0.16667]

--image_pol

RASCIL polarisation frame for image: stokesI | stokes IQ | stokesIQUV

Default: “stokesIQUV”

--vis_pol

RASCIL polarisation frame for visibility: linear | linearnp

Default: “linear”

--duration

Type of duration: long or medium or short

Default: “long”

--results

Directory for results

Default: “./”

--msname

Root name of MS (i.e. without .ms)

Default: “sim_mid_psi”

--split

In concat, type of tree e.g. 2->binary

Default: 2

--nthreads

Number of threads per worker

Default: 1

--processes

Number of processes per worker

Default: 1

--memory

Memory per worker (GB)

--nworkers

Number of workers

Default: 4

--use_dask

Use dask processing?

Default: “True”

--interface

Network interface

Default: “ib0”

Todo

• Insert todo’s here