PRIVAL

Name

prival

Purpose (one Line)

Reduce an angle to its principal value (0 $\leq \Theta < 2\pi$).

Description

This routine uses [0 to 2*PI) as the principal value of an angle. If
the angle is negative, 2*PI is added to the remainder of division by 2*PI.
If positive, then the value is the remainder of division by 2*PI. Nothing
is done to the input value if it is already in range.

Calling Sequence

result = prival( angle )

Inputs

angle : Angle to reduce to principal value (double).

Optional Input Parameters

Keyword Parameters

Outputs

result = Principal value of angle (double).

Common Blocks

Side Effects

Restrictions

Procedure

Modification History

Copyright (C) 1987, by Marc W. Buie
Version dated 86/2/1
Ported by Doug Loucks, Lowell Observatory, July 28, 1993, from the
C-language version written by Marc Buie.