# Elliptic_integral_rd

Elliptic-integral-rd-func

## Definition:

calculates an approximate value for the integral

where x, y ≥ 0, at most one of x and y is zero, and z > 0.

For more information please review the s21bcc function in the NAG document.

## Parameters:

- x (input, double)
- The argument x of the function.
- y (input, double)
- The argument y of the function.
- z (input, double)
- The argument z of the function.
- Constraint: x, y ≥ 0.0, z>0.0 and only one of x, y and z may be zero.
- Rd (output, double)
- Approximate value of the integral