Bessel_i_nu_scaled

Bessel-i-nu-scaled-func

Definition:

evaluates an approximation to the modified Bessel function of the first kind , where the order =-3, -2, -1, 1, 2 or 3 and x is real and positive. For positive orders it may also be called with x=0, since when > 0. For negative orders the formula

is used prior to multiplication by the scale factor .

For more information please review the s18ecc function in the NAG document.

Parameters:

x (input, double)

The argument x of the function.

Constraints:

x>0.0 when nu<0,
x???0.0 when nu>0.

(input, int)

The argument of the function.

Constraints:

(output, double)

Approximation of the modified Bessel function of the first kind.