Kelvin_ber

Kelvin-ber-func

Definition:

evaluates an approximation to the Kelvin function ber x.

The function is based on several Chebyshev expansions. For large x, there is a danger of the result being totally inaccurate, as the error amplification factor grows in an essentially exponential manner; therefore the function must fail.

For more information please review the s19aac function in the NAG document

Parameters:

x (input, double)

The argument x of the function.

ber (output, double)

Approximation of the Kelvin function ber x.