GEANT321/gtrak/gskpho.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.1  1999/05/18 15:55:21  fca
   6 * AliRoot sources
   7 *
   8 * Revision 1.1.1.1  1995/10/24 10:21:43  cernlib
   9 * Geant
  10 *
  11 *
  12 #include "geant321/pilot.h"
  13 *CMZ :  3.21/02 03/07/94  19.07.28  by  S.Giani
  14 *-- Author :
  15       SUBROUTINE GSKPHO (IGK)
  16 C.
  17 C.    ******************************************************************
  18 C.    *                                                                *
  19 C.    *                                                                *
  20 C.    *   Stores in stack JSTAK either the IGKth Cherenkov photon of   *
  21 C.    *   /GCKIN2/, or the NPHOT tracks when IGK is 0.                 *
  22 C.    *                                                                *
  23 C.    *   Called by : 'User'                                           *
  24 C.    *   Authors   : F.Carminati                                      *
  25 C.    *                                                                *
  26 C.    ******************************************************************
  27 C.
  28 #include "geant321/gcbank.inc"
  29 #include "geant321/gcjloc.inc"
  30 #include "geant321/gcking.inc"
  31 #include "geant321/gcnum.inc"
  32 #include "geant321/gcunit.inc"
  33 #include "geant321/gctrak.inc"
  34 #include "geant321/gcmzfo.inc"
  35 #include "geant321/gcstak.inc"
  36 #include "geant321/gckine.inc"
  37 *
  38       PARAMETER (NWPOLA=3)
  39 C.
  40 C.    ------------------------------------------------------------------
  41 C.
  42 *
  43 * *** Make sure the request is reasonable
  44       IF (NGPHOT.LE.0) GO TO 999
  45       IF (IGK.EQ.0) THEN
  46          N1 = 1
  47          N2 = NGPHOT
  48       ELSE
  49          IF (IGK.LT.0.OR.IGK.GT.NGPHOT) THEN
  50             WRITE(CHMAIL,10000) IGK, NGPHOT
  51 10000 FORMAT(' **** GSKPHO: ',I6,'th photon requested, ',
  52      + I6,' in stack')
  53             CALL GMAIL(0,0)
  54             GO TO 999
  55          ENDIF
  56          N1 = IGK
  57          N2 = IGK
  58       ENDIF
  59 *
  60 * *** Store photons in stack JSTAK
  61 *
  62 * *** Check that the bank is there and big enough
  63       IF (JSTAK.EQ.0) THEN
  64          NDBOOK = NTSTKP*NWSTAK +3
  65          NDPUSH = NTSTKS*NWSTAK
  66          CALL MZBOOK (IXCONS,JSTAK,JSTAK,1,'STAK', 1,1,NDBOOK, IOSTAK,3)
  67          IQ(JSTAK+2) = NTSTKP
  68       ENDIF
  69       IF(IQ(JSTAK-2).EQ.0) THEN
  70          CALL MZPUSH(IXCONS,JSTAK,1,0,'I')
  71       ENDIF
  72       IF(LQ(JSTAK-1).EQ.0) THEN
  73          CALL MZBOOK(IXCONS,JPOLAR,JSTAK,-1,'POLA',0,0,
  74      +               NTSTKP*NWPOLA,3,-1)
  75       ENDIF
  76       MISSNG=IQ(JSTAK+1)+N2-N1+1-IQ(JSTAK+2)
  77       IF (MISSNG.GT.0) THEN
  78          CALL MZPUSH (IXCONS, JSTAK, 0, MISSNG*NWSTAK+NDPUSH, 'I')
  79          IQ(JSTAK+2) = IQ(JSTAK+2) +NTSTKS+MISSNG
  80       ENDIF
  81       MSSPOL = IQ(JSTAK+1)+N2-N1+1-IQ(JPOLAR-1)/3
  82       IF(MSSPOL.GT.0) THEN
  83          CALL MZPUSH (IXCONS,JPOLAR,0,(NTSTKS+MSSPOL)*NWPOLA, 'I')
  84       ENDIF
  85 *
  86 * *** Now we can go
  87       DO 20  NN=N1,N2
  88          JST = JSTAK  +IQ(JSTAK+1)*NWSTAK +3
  89          JPO = JPOLAR +IQ(JSTAK+1)*NWPOLA
  90          IQ(JSTAK+1) = IQ(JSTAK+1) +1
  91          IF (IQ(JSTAK+3).EQ.0) IQ(JSTAK+3) = IQ(JSTAK+1)
  92          IF (IQ(JSTAK+1).GT.NSTMAX) NSTMAX = IQ(JSTAK+1)
  93 *
  94          IQ(JST+1) = -ITRA
  95          IQ(JST+2) = IPART
  96          IQ(JST+3) = 0
  97          DO 10 I = 1,3
  98             Q(JST+3+I) = XPHOT(I  ,NN)
  99             Q(JST+6+I) = XPHOT(I+3,NN)*XPHOT(7,NN)
 100             Q(JPO+  I) = XPHOT(I+7,NN)
 101    10    CONTINUE
 102          Q(JST+10) = XPHOT(11,NN)
 103          Q(JST+11) = SAFETY
 104          Q(JST+12) = UPWGHT
 105 *
 106          NALIVE = NALIVE +1
 107    20 CONTINUE
 108 *                                                             END GSKPHO
 109   999 END