NAG CL Interface
s15afc returns a value for Dawson's Integral, .
The function may be called by the names: s15afc, nag_specfun_dawson or nag_dawson.
evaluates an approximation for Dawson's Integral
The function is based on two Chebyshev expansions:
, and for
. These approximations are used for those values of
for which the result is correct to machine precision
On entry: the argument of the function.
Error Indicators and Warnings
Let and be the relative errors in the argument and result respectively.
is considerably greater than the machine precision
is due to data errors etc.), then
are approximately related by:
The following graph shows the behaviour of the error amplification factor
However, if is of the same order as machine precision, then rounding errors could make somewhat larger than the above relation indicates. In fact will be largely independent of or , but will be of the order of a few times the machine precision.
Parallelism and Performance
s15afc is not threaded in any implementation.
This example reads values of the argument from a file, evaluates the function at each value of and prints the results.