CLEAN_ARES Absolute residual (ARES)
CLEAN_FRES Fractional residual (FRES)
CLEAN_NITER Maximum number of iterations (NITER)
CLEAN_KEEP Number of iterations used to check convergence (see below)
CLEAN_METHOD Cleaning Method (METHOD)
CLEAN_GAIN Loop gain (GAIN)
CLEAN_MAJOR Maximum number of Major cycles (Nmajor)
CLEAN_SEARCH Minimum primary beam threshold for searching (Search_W)
CLEAN_RESTORE Minimum primary beam threshold for restoring (Restore_W)
CLEAN_SPEEDY Speeding factor for Clark (Spexp)
CLEAN_WORRY "Worry" factor for Clark (Worry)
CLEAN_SMOOTH Smoothing factor for Multi Scale Clean (Smooth)
CLEAN_RATIO Ratio for Dual Resolution clean (Ratio)
CLEAN_NGOAL A number of components for ALMA joint deconvolution only (Ngoal)
Clean convergence is controlled by the usual ARES, FRES and NITER criteria, plus CLEAN_MAJOR for methods with major cycles. However, these criteria can be set to 0, allowing Mapping to automatically guess when to stop. In this case, convergence is controlled by CLEAN_KEEP, which is a number of components. Deconvolution of a given channel stops if the cumulative flux at iteration number N is smaller (resp. larger) than at iteration N-CLEAN_KEEP for positive signals (resp. negative). In essence, CLEAN_KEEP is the number of components when only noise is present. Experimentation with various types of images have shown that CLEAN_KEEP = 70 is a good compromise.