If flt.zero_niter is non-zero, it gives the number of iterations for which the FLT model should be masked. Subsequent iterations are not masked. A value of zero means " mask on all iterations" . However, if parameter "flt.zero_notlast" is set, the mask will will not be applied on the last iteration, even if flt.zero_niter is zero. Note, using FLT masking on many iterations can inhibit convergence. Also, any initial iterations specified by parameter "ast.skip" are not included in the count of iterations. A negative value will disable all masking of the FLT model. This parameter controls the masking requested via parameter "flt.clip" , in addition to the masking requested via the " flt.zero_xxx" set of parameters. [2]

MAKEMAP, CALCQU