S18GKF evaluates a sequence of values for the Bessel function of the first kind
, where
is complex and nonzero and
is the order with
. The
-member sequence is generated for orders
when
. Note that
is replaced by
when
. For positive orders the routine may also be called with
, since
when
. For negative orders the formula
is used to generate the required sequence. The appropriate values of
and
are obtained by calls to
S17DCF and
S17DEF.
If on entry
or
, explanatory error messages are output on the current error message unit (as defined by
X04AAF).
All constants in
S17DCF and
S17DEF
are specified to approximately
digits of precision. If
denotes the number of digits of precision in the floating point arithmetic being used, then clearly the maximum number of correct digits in the results obtained is limited by
. Because of errors in argument reduction when computing elementary functions inside
S17DCF and
S17DEF, the actual number of correct digits is limited, in general, by
,
where
represents the number of digits lost due to the argument reduction. Thus the larger the values of
and
, the less the precision in the result.
None.