Baseline specification

A baseline specification consists of an ANT followed by an operator or a pair of antenna specifications separated by an operator. Operator can be one, two or three ampersands ('&'):

Table 1: Table of allowed baseline selection operators and their meaning.

The operator	Operation
&	Select only cross-correlation data
&&	Select cross- and auto-correlation data
&&&	Select only auto-correlation data

Possible forms of baseline specifications are tabulated in Table 2.

Table 2: Baseline specification syntax: ANT, ANT1 and ANT2 represent a comma-separated list of antennas.

Specification	Meaning
ANT	Select only cross-correlation baselines between all the
	antennas in ANT and all other available antennas
ANT&	Select only cross-correlation baselines between antennas
	in ANT only
ANT1 & ANT2	Select only cross-correlation baselines between
	antennas in ANT1 and ANT2
ANT&&	Select cross- and auto-correlation baselines
	between all the antennas in ANT only
ANT&&*	Select cross- and auto-correlation baselines
	between all the antennas in ANT and all other
	available antennas
ANT1 && ANT2	Select cross- and auto-correlation baselines
	between antennas in ANT1 and ANT2
ANT&&&	Select only auto-correlation baselines for
	antennas in ANT
!ANT	Excludes all baselines involving antennas in ANT.
	ANT can be any of the above expressions
ANT1 ; !ANT2	ANT1 and ANT2 can be any of the above expressions.
	This selects only cross-correlation baselines
	between all the antennas in ANT1 and all
	other available antennas except those involving
	antennas in ANT2.

Formally, baseline specification is of the form [!]ANT[$<$ OP$>$ [ANT]] (where the parts in square brackets are optional and $<$ OP$>$ can be '&', '&&' or '&&&').