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SUBROUTINE slDC2S (V, A, B)
*+
* - - - - - -
* D C 2 S
* - - - - - -
*
* Cartesian to spherical coordinates (double precision)
*
* Given:
* V d(3) x,y,z vector
*
* Returned:
* A,B d spherical coordinates in radians
*
* The spherical coordinates are longitude (+ve anticlockwise looking
* from the +ve latitude pole) and latitude. The Cartesian coordinates
* are right handed, with the x axis at zero longitude and latitude, and
* the z axis at the +ve latitude pole.
*
* If V is null, zero A and B are returned. At either pole, zero A is
* returned.
*
* Last revision: 22 July 2004
*
* Copyright P.T.Wallace. All rights reserved.
*
* License:
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (see SLA_CONDITIONS); if not, write to the
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA
*
* Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.
*-
IMPLICIT NONE
DOUBLE PRECISION V(3),A,B
DOUBLE PRECISION X,Y,Z,R
X = V(1)
Y = V(2)
Z = V(3)
R = SQRT(X*X+Y*Y)
IF (R.EQ.0D0) THEN
A = 0D0
ELSE
A = ATAN2(Y,X)
END IF
IF (Z.EQ.0D0) THEN
B = 0D0
ELSE
B = ATAN2(Z,R)
END IF
END
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