The user can control the algorithm through SIC variables. Values of those
variables can be checked through either "INPUT UV__MAP|CLEAN|UVALL" or
"EXAMINE VARIABLE". New values can be given using "LET VARIABLE value".
For ease of use, and whenever it is possible, a sensible value of each
parameter will automatically be computed from the context if the value of
the corresponding variable is set to its default value, i.e. zero value
and empty string. A few variables are initialized to "reasonable" values.
