GEANT321/gstrag/gdifmg.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.1  1999/05/18 15:55:20  fca
   6 * AliRoot sources
   7 *
   8 * Revision 1.1.1.1  1995/10/24 10:21:37  cernlib
   9 * Geant
  10 *
  11 *
  12 #include "geant321/pilot.h"
  13 #if defined(CERNLIB_ASHO)
  14 *CMZ :  3.21/02 29/03/94  15.41.25  by  S.Giani
  15 *-- Author :
  16       SUBROUTINE GDIFMG(DEL)
  17
  18 #include "geant321/gccuts.inc"
  19 #include "geant321/gcasho.inc"
  20 C-----------------------------------------------------------------------
  21 C      This program calculates the final distribution coef-
  22 C      ficients until the integral S is more or equal to L2.
  23 C      In case of S < L2 or miscalculations due to FORTRAN
  24 C      limits DONE = FALSE.
  25 C-----------------------------------------------------------------------
  26 C      Update history: 10-08-93
  27 C
  28 C-----------------------------------------------------------------------
  29       REAL BN(50),BNA(50),L2
  30       INTEGER FLMAX
  31       PARAMETER (DL2=.1)
  32       DATA CORMAX/80./
  33 C-----------------------------------------------------------------------
  34 C      Initialization steps
  35 C-----------------------------------------------------------------------
  36       XX = 0.
  37       Z = 1.
  38       DO 10 K=1,NOSC
  39          BN(K) = BOSC(K)*IOSC(K)
  40          BNA(K) = BN(K)*(AOSC(K) - 1.)
  41          XX = XX + AOSC(K)*BOSC(K)
  42    10 CONTINUE
  43 C
  44       FLMAX = 0
  45       CORR = CORMAX - XX
  46       CMGO(1) = EXP(-CORMAX)
  47       CMGO(2) = CMGO(1)*BNA(1)
  48       Z = Z-(CMGO(1)+CMGO(2))*EXP(CORR)
  49 C-----------------------------------------------------------------------
  50 C      Calculation of the current Ci
  51 C-----------------------------------------------------------------------
  52       CALL GRNDM(RNDM,1)
  53
  54       L2 = DL2
  55       IF (RNDM.GE.L2) THEN
  56          L2 = RNDM
  57          FLMAX = 1
  58       ENDIF
  59       DO 40 NMGO=3,NMGOMA
  60          CMGO(NMGO) = CMGO(NMGO - 1)*BNA(1)
  61          DO 30 J = 1,NMGO - 2
  62             M = NMGO - 1 - J
  63             X = BOSC(1)/J
  64             DO 20 K=2,NOSC
  65                IF(MOD(J+1,IOSC(K)).EQ.0) THEN
  66                   L = (J+1)/IOSC(K)
  67                   IF(L.EQ.1) THEN
  68                      X = X + BNA(K)
  69                   ELSE
  70                      X = X + BN(K)/(L-1)
  71                   ENDIF
  72                ENDIF
  73    20       CONTINUE
  74             CMGO(NMGO) = CMGO(NMGO) + X*CMGO(M)
  75    30    CONTINUE
  76          CMGO(NMGO) = CMGO(NMGO)/(NMGO-1)
  77          Z = Z - CMGO(NMGO)*EXP(CORR)
  78          IF (Z.LE.L2) GOTO 50
  79    40 CONTINUE
  80
  81    50 IF (FLMAX.EQ.1) THEN
  82          DEL = (NMGO-1)*EOSC(1)
  83       ELSE
  84          DEL = (NMGO-1)*EOSC(1)*L2/RNDM
  85       ENDIF
  86       IF (DEL.GE.DCUTE*1E6) DEL = DCUTE*1E6
  87
  88       END
  89 #else
  90       SUBROUTINE GDIFMG_DUMMY
  91       END
  92 #endif