1*-----------------------------------------------------------------------
2*     COORDINATE TRANSFORMATION (3D CARTESIAN -> SPHERICAL)
3*                                              93/02/18   S.SAKAI
4*-----------------------------------------------------------------------
5*     Copyright (C) 2000-2004 GFD Dennou Club. All rights reserved.
6*-----------------------------------------------------------------------
7      SUBROUTINE CT3CS(X, Y, Z, R, THETA, PHI)
8
9*                  0 < THETA < PI
10*                -PI < PHI   < PI
11
12
13      R     = SQRT(X*X + Y*Y + Z*Z)
14      PHI   = ATAN2(Y, X)
15      THETA = ATAN2(SQRT(X*X + Y*Y), Z)
16
17      END
18