Abstract

   CSPICE_PI returns the double precision value of the constant PI.

I/O

   The call:

      pi = cspice_pi(  )

   returns:

      pi       the value of pi (the ratio of a circle's circumference to its
               diameter), determined by the acos function.

               help, pi
                  DOUBLE = Scalar

               That is,

                     cspice_pi = acos ( -1.0 )

Parameters

   None.

Examples

   Any numerical results shown for this example may differ between
   platforms as the results depend on the SPICE kernels used as input
   and the machine specific arithmetic implementation.

   1) The following code example returns the double precision value of
      the constant pi and prints it out.

      Example code begins here.


      PRO pi_ex1

          ;;
          ;; Print the double precision value of PI
          ;;
          print, FORMAT='("Pi: ",F25.22)', cspice_pi()

      END


      When this program was executed on a Mac/Intel/IDL8.x/64-bit
      platform, the output was:


      Pi:  3.1415926535897931159980


      Note that the IDL system variable !DPI returns a double precision
      value for PI that equates the value returned by cspice_pi, to
      machine roundoff.

      The IDL system variable !PI returns a single precision (float)
      value for PI that equates to the value returned by the expression

         float( cspice_pi() )

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.

Exceptions

   Error free.

Files

   None.

Restrictions

   None.

Required_Reading

   ICY.REQ

Literature_References

   None.

Author_and_Institution

   J. Diaz del Rio     (ODC Space)
   E.D. Wright         (JPL)

Version

   -Icy Version 1.0.2, 25-AUG-2021 (JDR)

       Edited the header to comply with NAIF standard. Added example's
       problem statement and reformatted example's output.

       Added -Parameters, -Particulars, -Exceptions, -Files, -Restrictions,
       -Literature_References and -Author_and_Institution sections.

       Removed reference to the routine's corresponding CSPICE header from
       -Abstract section.

       Added argument's type and size information in the -I/O section.

   -Icy Version 1.0.1, 13-JUN-2010 (EDW)

      Minor edit to code comments eliminating typo.

   -Icy Version 1.0.0, 16-JUN-2003 (EDW)

Index_Entries

   value of pi