GEANT321/gstrag/gdifmg.F

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