ELK Function

Evaluates the complete elliptic integral of the kind K(x).

Usage

result = ELK(x)

Input Parameters

x—Argument for which the function value is desired.

Returned Value

result —The complete elliptic integral K(x).

Input Keywords

Double—If present and nonzero, double precision is used.

Discussion

The complete elliptic integral of the first kind is defined to be:

 

The argument x must satisfy 0 £ x < 1; otherwise, ELK returns the largest representable floating-point number.

The function K(x) is computed using the ELRF Function and the relation K(x) = R_F(0, 1 - x, 1).

Example

The integral K(0) is evaluated.

PRINT, ELK(0.0)

; PV-WAVE prints: 1.57080