Procedure

     RPD ( Radians per degree )

     DOUBLE PRECISION FUNCTION RPD ( )

Abstract

     Return the number of radians per degree.

Required_Reading

     None.

Keywords

     CONSTANTS

Declarations

    None.

Brief_I/O

     The function returns the number of radians per degree.

Detailed_Input

     None.

Detailed_Output

     The function returns the number of radians per degree: pi/180.
     The value of pi is determined by the ACOS function. That is,

           RPD = ACOS ( -1.D0 ) / 180.D0

Parameters

     None.

Exceptions

     Error free.

Files

     None.

Particulars

     The first time the function is referenced, the value is computed
     as shown above. The value is saved, and returned directly upon
     subsequent reference.

Examples

     The code fragment below illustrates the use of RPD.

        C
        C     Convert all input angles to radians.
        C
              CLOCK = CLOCK * RPD()
              CONE  = CONE  * RPD()
              TWIST = TWIST * RPD()

     or equivalently,

        C
        C     Convert all input angles to radians.
        C
              CALL VPACK  ( CLOCK, CONE, CCTWIST, ALBTGAM )
              CALL VSCL   ( RPD(), ALBTGAM, ALBTGAM )
              CALL VUPACK ( ALBTGAM, CLOCK, CONE, CCTWIST )

Restrictions

     None.

Literature_References

     None.

Author_and_Institution

     J. Diaz del Rio    (ODC Space)
     W.L. Taber         (JPL)
     I.M. Underwood     (JPL)

Version

    SPICELIB Version 1.0.2, 08-JUL-2020 (JDR)

        Edited the header to comply with NAIF standard.

    SPICELIB Version 1.0.1, 10-MAR-1992 (WLT)

        Comment section for permuted index source lines was added
        following the header.

    SPICELIB Version 1.0.0, 31-JAN-1990 (WLT) (IMU)