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/*============================================================================
*
* WCSLIB - an implementation of the FITS WCS proposal.
* Copyright (C) 1995-2002, Mark Calabretta
*
* This library 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 2 of the License, or (at your option) any later version.
*
* This library 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 Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Correspondence concerning WCSLIB may be directed to:
* Internet email: mcalabre@atnf.csiro.au
* Postal address: Dr. Mark Calabretta,
* Australia Telescope National Facility,
* P.O. Box 76,
* Epping, NSW, 2121,
* AUSTRALIA
*
*=============================================================================
*
* The functions defined herein are trigonometric or inverse trigonometric
* functions which take or return angular arguments in decimal degrees.
*
* $Id: wcstrig.c,v 2.8 2002/04/03 01:25:29 mcalabre Exp $
*---------------------------------------------------------------------------*/
#include <math.h>
#include "wcslib.h"
const double d2r = PI / 180.0;
const double r2d = 180.0 / PI;
double cosdeg (angle)
const double angle;
{
double resid;
resid = fabs(fmod(angle,360.0));
if (resid == 0.0) {
return 1.0;
} else if (resid == 90.0) {
return 0.0;
} else if (resid == 180.0) {
return -1.0;
} else if (resid == 270.0) {
return 0.0;
}
return cos(angle*d2r);
}
/*--------------------------------------------------------------------------*/
double sindeg (angle)
const double angle;
{
double resid;
resid = fmod(angle-90.0,360.0);
if (resid == 0.0) {
return 1.0;
} else if (resid == 90.0) {
return 0.0;
} else if (resid == 180.0) {
return -1.0;
} else if (resid == 270.0) {
return 0.0;
}
return sin(angle*d2r);
}
/*--------------------------------------------------------------------------*/
double tandeg (angle)
const double angle;
{
double resid;
resid = fmod(angle,360.0);
if (resid == 0.0 || fabs(resid) == 180.0) {
return 0.0;
} else if (resid == 45.0 || resid == 225.0) {
return 1.0;
} else if (resid == -135.0 || resid == -315.0) {
return -1.0;
}
return tan(angle*d2r);
}
/*--------------------------------------------------------------------------*/
double acosdeg(v)
const double v;
{
if (v >= 1.0) {
if (v-1.0 < WCSTRIG_TOL) return 0.0;
} else if (v == 0.0) {
return 90.0;
} else if (v <= -1.0) {
if (v+1.0 > -WCSTRIG_TOL) return 180.0;
}
return acos(v)*r2d;
}
/*--------------------------------------------------------------------------*/
double asindeg (v)
const double v;
{
if (v <= -1.0) {
if (v+1.0 > -WCSTRIG_TOL) return -90.0;
} else if (v == 0.0) {
return 0.0;
} else if (v >= 1.0) {
if (v-1.0 < WCSTRIG_TOL) return 90.0;
}
return asin(v)*r2d;
}
/*--------------------------------------------------------------------------*/
double atandeg (v)
const double v;
{
if (v == -1.0) {
return -45.0;
} else if (v == 0.0) {
return 0.0;
} else if (v == 1.0) {
return 45.0;
}
return atan(v)*r2d;
}
/*--------------------------------------------------------------------------*/
double atan2deg (y, x)
const double x, y;
{
if (y == 0.0) {
if (x >= 0.0) {
return 0.0;
} else if (x < 0.0) {
return 180.0;
}
} else if (x == 0.0) {
if (y > 0.0) {
return 90.0;
} else if (y < 0.0) {
return -90.0;
}
}
return atan2(y,x)*r2d;
}
/* Dec 20 1999 Doug Mink - Change cosd() and sind() to cosdeg() and sindeg()
* Dec 20 1999 Doug Mink - Include wcslib.h, which includes wcstrig.h
* Dec 20 1999 Doug Mink - Use PI from wcslib.h, not locally defined
*
* Sep 19 2001 Doug Mink - No change for WCSLIB 2.7
*/
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