msmerge (Measurement Merging Utility)

The msmerge utility is used to merge measurement sets in frequency.

The intended use-cases of this tool are:

• Merge measurement sets from different frequency sub-bands into a single measurement set. It is used, for example, to create a single simulated measurement set when one needs to split a simulation into sub-bands or to combine the channel ranges for a single beam from the sub-band single beam files produced by ingest.

It is assumed all input files have the same number of channels and are listed in the correct order to combine them into the full spectrum output.

Running the program

It can be run with the following command

$ msmerge -o output_file list_of_input_files

The msmerge program is not parallel/distributed, it runs in a single process.

Configuration Parameters

At this time msmerge does not accept a configuration parameter file. However it has a number of command line flags

-x <n> : specify the output tile size for correlations/polarisations
-c <n> : specify the output tile size for channels
-r <n> : specify the output tile size for rows
-o <output file> : specify the output MeasurementSet
-i <input files> : specify the input files (or just list them at the end)

The default tiling is 4 polarizations, 1 channel, and as many rows as can be cached efficiently.

Example

Example 1:

$ msmerge -o fullband.ms subband_???.ms

Example 2:

$ msmerge -x 4 -c 54 -o output.ms channel1.ms channel2.ms channel3.ms