The routine uses the same Chebyshev expansions as
s18aff, which returns the unscaled value of
.
There are no actual failure exits from this routine.
ifail is always set to zero. This argument is included for compatibility with other routines in this chapter.
Relative errors in the argument are attenuated when propagated into the function value. When the accuracy of the argument is essentially limited by the machine precision, the accuracy of the function value will be similarly limited by at most a small multiple of the machine precision.
None.