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Using the sortandselect module

Data sorting and selection is provided by the sortandselect module. For example, to sort by TIME:

include "synthesis.g";
sortms('3C84.sortedms', '3C84.ms', 'TIME');

To select a UV range:

include "synthesis.g";
selectuvrangems('3C84.selectedms', '3C84.ms', '100m', '3000m')

Sometimes one wishes to solve for the calibration using a subset of the visibility data, such as a limited uv range. To do this, use the selectuvrangems function to generate a reference MeasurementSet and then do the solution using that data set.

include "synthesis.g"
di.derive_model()
selectuvrangems('3C273XC1.uv.MS', '3C273XC1.MS', 100.0, 1000.0);
di.MS:='3C273XC1.uv.MS'
di.derive_ft()
di.T.t:=300
di.T.phaseOnly:=T
di.T.solve:=T
di.T.table:="tcal"
di.solve_cal()
di.MS:='3C273XC1.MS'
di.apply_cal()

This is a sophisticated example in which we do the solution for a limited uvrange, and transfer the tables to the full MeasurementSet. The function selectuvrangems creates a MeasurementSet with only samples with uv coordinates in the specified range in radius. We then Fourier transform the derivedmodel image di.images.derivedmodel and solve for and applies calibration for the T component, reading from and writing to the table tcal. The calibration is then applied to the original MeasurementSet.

For more information, see the module documentation for sortandselect.

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