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IMSL_ELRC

IMSL_ELRC

The IMSL_ELRC function evaluates an elementary integral from which inverse circular functions, logarithms and inverse hyperbolic functions can be computed.

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 third kind is defined to be:

The argument X must be nonnegative, Y must be positive, and X + y must be less than or equal to b/5 and greater than or equal to 5s. If any of these conditions are false, the IMSL_ELRC is set to b. Here, b is the largest and s is the smallest representable floating-point number.

The IMSL_ELRC function is based on the code by Carlson and Notis (1981) and the work of Carlson (1979).

Example


The integral RC (2.25, 2) is computed.

PRINT, IMSL_ELRC(2.25, 2.0)
  0.693147

Syntax


Result = IMSL_ELRC(X, Y [, /DOUBLE]

Return Value


The elliptic integral RC (x, i).

Arguments


X

First argument for which the function value is desired. It must be nonnegative and must satisfy the conditions given in the description.

Y

Second argument for which the function value is desired. It must be nonnegative and must satisfy the conditions given in the description.

Keywords


DOUBLE (optional)

If present and nonzero, double precision is used.

Version History


6.4

Introduced



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