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slalib/cs2c6.f

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+      SUBROUTINE sla_CS2C6 ( A, B, R, AD, BD, RD, V )
+*+
+*     - - - - - -
+*      C S 2 C 6
+*     - - - - - -
+*
+*  Conversion of position & velocity in spherical coordinates
+*  to Cartesian coordinates (single precision)
+*
+*  Given:
+*     A     r      longitude (radians)
+*     B     r      latitude (radians)
+*     R     r      radial coordinate
+*     AD    r      longitude derivative (radians per unit time)
+*     BD    r      latitude derivative (radians per unit time)
+*     RD    r      radial derivative
+*
+*  Returned:
+*     V     r(6)   Cartesian position & velocity vector
+*
+*  Last revision:   11 September 2005
+*
+*  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., 59 Temple Place, Suite 330, 
+*    Boston, MA  02111-1307  USA
+*
+*-
+
+      IMPLICIT NONE
+
+      REAL A, B, R, AD, BD, RD, V(6)
+
+      REAL SA, CA, SB, CB, RCB, X, Y, RBD, W
+
+
+
+*  Useful functions.
+      SA = SIN(A)
+      CA = COS(A)
+      SB = SIN(B)
+      CB = COS(B)
+      RCB = R*CB
+      X = RCB*CA
+      Y = RCB*SA
+      RBD = R*BD
+      W = RBD*SB-CB*RD
+
+*  Position.
+      V(1) = X
+      V(2) = Y
+      V(3) = R*SB
+
+*  Velocity.
+      V(4) = -Y*AD-W*CA
+      V(5) = X*AD-W*SA
+      V(6) = RBD*CB+SB*RD
+
+      END