GEANT321/ggeom/gsaphi.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.1  1995/10/24 10:20:55  cernlib
   6 * Geant
   7 *
   8 *
   9 #include "geant321/pilot.h"
  10 *CMZ :  3.21/02 29/03/94  15.41.30  by  S.Giani
  11 *-- Author :
  12       SUBROUTINE GSAPHI(V,PHIL,PHIH,SAF)
  13 C.
  14 C.    ******************************************************************
  15 C.    *                                                                *
  16 C.    *                                                                *
  17 C.    *    Subroutine GSAPHI computes the 'safety radius' from the     *
  18 C.    *    point V to phi limits PHIL and PHIH. The safety radius is   *
  19 C.    *    returned in SAF.                                            *
  20 C.    *       A.C.McPherson   5th Sept. 1984.                          *
  21 C.    *                                                                *
  22 C.    ******************************************************************
  23 C.
  24 #include "geant321/gconsp.inc"
  25 C
  26       DIMENSION V(3)
  27 C
  28       R=V(1)**2+V(2)**2
  29       IF(R.GT.0.0) R=SQRT(R)
  30 C
  31       PHL=PHIL*DEGRAD
  32       PHH=PHIH*DEGRAD
  33 C
  34 C              Check for case of complete 360 degree region.
  35 C
  36       SAF=BIG
  37       DPHI=PHIH-PHIL
  38       IF(DPHI.LE.0.0) DPHI=DPHI+360.0
  39       IF(DPHI.GE.360.0) GO TO 10
  40 C
  41       SAF=R
  42       SL=SIN(PHL)
  43       CL=COS(PHH)
  44       IF(SL*V(2)+CL*V(1).GT.0.0) SAF=ABS(SL*V(1)-CL*V(2))
  45 C
  46       SAF2=R
  47       SH=SIN(PHH)
  48       CH=COS(PHH)
  49       IF(SH*V(2)+CH*V(1).GT.0.0) SAF2=ABS(SH*V(1)-CH*V(2))
  50 C
  51       IF(SAF2.LT.SAF) SAF=SAF2
  52 C
  53    10 CONTINUE
  54       RETURN
  55       END