The IMSL_ELRF function evaluates Carlson’s elliptic integral of the first kind RF(x, y, z).
This routine requires an IDL Advanced Math and Stats license. For more information, contact your sales or technical support representative.
Carlson’s elliptic integral of the second kind is defined to be:
The arguments must be nonnegative and less than or equal to b/5. In addition, x + y, x + z, and y + z must be greater than or equal to 5s. Should any of these conditions fail, IMSL_ELRF is set to b. Here, b is the largest and is the smallest representable number.
The IMSL_ELRF function is based on the code by Carlson and Notis (1981) and the work of Carlson (1979).
Example
The integral RF(0, 1, 2) is computed.
PRINT, IMSL_ELRF(0.0, 1.0, 2.0)
1.31103
Syntax
Result = IMSL_ELRF(X, Y, Z [, /DOUBLE]
Return Value
The complete elliptic integral RF(x, y, z).
Arguments
X
First argument for which the function value is desired. It must be nonnegative.
Y
Second argument for which the function value is desired. It must be nonnegative.
Z
Third argument for which the function value is desired. It must be positive.
Keywords
DOUBLE (optional)
If present and nonzero, double precision is used.
Version History