/*
*+
* Name:
* palDrange
* Purpose:
* Normalize angle into range +/- pi
* Language:
* Starlink ANSI C
* Type of Module:
* Library routine
* Invocation:
* palDrange( double angle )
* Arguments:
* angle = double (Given)
* The angle in radians.
* Description:
* The result is "angle" expressed in the range +/- pi. If the
* supplied value for "angle" is equal to +/- pi, it is returned
* unchanged.
* Authors:
* DSB: David S Berry (JAC, Hawaii)
* PTW: Patrick T. Wallace
* {enter_new_authors_here}
* History:
* 2012-05-09 (DSB):
* Initial version with documentation taken from Fortran SLA
* Adapted with permission from the Fortran SLALIB library.
* {enter_further_changes_here}
* Copyright:
* Copyright (C) 1995 Rutherford Appleton Laboratory
* Copyright (C) 2012 Science and Technology Facilities Council.
* All Rights Reserved.
* Licence:
* This program is free software: you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, either
* version 3 of the License, or (at your option) any later
* version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* License along with this program. If not, see
* .
* Bugs:
* {note_any_bugs_here}
*-
*/
#include "pal.h"
#include "palmac.h"
#include
double palDrange( double angle ){
double result = fmod( angle, PAL__D2PI );
if( result > PAL__DPI ) {
result -= PAL__D2PI;
} else if( result < -PAL__DPI ) {
result += PAL__D2PI;
}
return result;
}