*
* $Id: match.F,v 1.1.1.1 1996/01/11 14:14:40 mclareni Exp $
*
* $Log: match.F,v $
* Revision 1.1.1.1  1996/01/11 14:14:40  mclareni
* Cojets
*
*
#include "cojets/pilot.h"
      SUBROUTINE MATCH(IWG,WGTCAS)
C     ****************************
C-- MATCHES PARTONS FROM INITIAL CASCADES (CALLED BY PREGEN)
#if defined(CERNLIB_SINGLE)
      IMPLICIT REAL (A-H,O-Z)
#endif
#if defined(CERNLIB_DOUBLE)
      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
#endif
#include "cojets/alqgen.inc"
#include "cojets/bkwg.inc"
#include "cojets/entrev.inc"
#include "cojets/event.inc"
#include "cojets/inmat.inc"
#include "cojets/itapes.inc"
#include "cojets/maxn.inc"
#include "cojets/mflain.inc"
#include "cojets/nevol.inc"
#include "cojets/nflav.inc"
#include "cojets/nkinpt.inc"
#include "cojets/parq.inc"
#include "cojets/qcds.inc"
#include "cojets/thrfla.inc"
      DIMENSION WFDSDT(6)
C
C-- PREENTERING
      DO 10 IB=1,2
      IBEAM=IB
      NBOOK(IBEAM)=0
      ICANC(IBEAM)=0
      ZERO=0.
      CALL Q2GEN(IFLAIN(IB),ZERO,Y,QSQ)
      XM=(PXIN(IB)**2+PYIN(IB)**2)/(S*XIN(IB))
      CALL BOOK(IFLAIN(IB),0,XM,Y,XIN(IB),PXIN(IB),PYIN(IB),ZERO,YF)
10    CONTINUE
C
C-- MAIN LOOP
      DO 200 M=1,NALQ
      YQSQ=LOG(ALQI+DALQ*FLOAT(M))
      NENTR=0
      DO 100 IB=1,2
      IBEAM=IB
      NB=NBOOK(IB)
      ICANC(IB)=0
C-- EVOLVE ONE  M  STEP FURTHER
      DO 90 J=1,NB
      Y=PARACT(J,4,IB)
      IF(Y.GT.YQSQ) GO TO 90
      JX=J
      IBACK(IBEAM)=0
      CALL EVOL(JX,YQSQ)
      MNBOOK=MAX(MNBOOK,NBOOK(IB))
90    CONTINUE
      IF(ICANC(IB).EQ.0) GO TO 100
C-- CANCEL DECAYED QUANTA
      ICN=ICANC(IB)
      DO 91 I=1,ICN
      IN=NBKCNC(I,IB)
91    PARACT(IN,1,IB)=0.
      JC=0
      NB=NBOOK(IB)
      DO 92 J=1,NB
      JZ=PARACT(J,1,IB)
      IF(JZ.EQ.0) GO TO 92
      JC=JC+1
      DO 93 L=1,9
93    PARACT(JC,L,IB)=PARACT(J,L,IB)
92    CONTINUE
      NBOOK(IB)=NBOOK(IB)-ICN
      ICANC(IB)=0
100   CONTINUE
      NB1=NBOOK(1)
      NB2=NBOOK(2)
      IF(NB1.EQ.0.OR.NB2.EQ.0) RETURN
C-- CALCULATION OF HARD WEIGHT AND BOOKING
      DO 110 J1=1,NB1
      IF(YQSQ.LT.PARACT(J1,8,1)) GO TO 110
      IF(YQSQ.GT.PARACT(J1,9,1)) GO TO 110
      IFLA1=PARACT(J1,1,1)
      XM1=PARACT(J1,3,1)
      XP1=PARACT(J1,5,1)
      PX1=PARACT(J1,6,1)
      PY1=PARACT(J1,7,1)
      MFLA1=ABS(IFLA1)
      NENT1=0
      DO 120 J2=1,NB2
      IF(YQSQ.LT.PARACT(J2,8,2)) GO TO 120
      IF(YQSQ.GT.PARACT(J2,9,2)) GO TO 120
      IFLA2=PARACT(J2,1,2)
      XM2=PARACT(J2,3,2)
      XP2=PARACT(J2,5,2)
      PX2=PARACT(J2,6,2)
      PY2=PARACT(J2,7,2)
      MFLA2=ABS(IFLA2)
      NENT2(J2)=0
      SHAT=(XP1*XP2+XM1*XM2)*S-2.*(PX1*PX2+PY1*PY2)
      IF(SHAT.LT.3.*Q2VECT(M)) GO TO 120
      IF(KPRHEV.EQ.0) GO TO 271
      IF(KPRHEV.EQ.1.AND.SHAT.LE.THRFLA(KFRFLA)) GO TO 120
      IF(KPRHEV.EQ.2.AND.SHAT.LE.AM2HEV(KFRFLA)) GO TO 120
271   CONTINUE
      NENT1=1
      NENT2(J2)=1
      IM=IMATCH(MFLA1,MFLA2)
      IF(IM.NE.2) GO TO 122
      IF(IFLA1*IFLA2.LT.0) IM=3
122   CONTINUE
      IF(IM.NE.9) GO TO 132
      IF(IFLA1*IFLA2.LT.0) IM=10
132   CONTINUE
      IF(KPRHEV.EQ.0.OR.KPRHEV.GE.3) GO TO 272
      IF(KPRHEV.EQ.1) GO TO 273
      IF(KPRHEV.EQ.2) GO TO 274
273   IF(IM.NE.3.AND.IM.NE.5.AND.IM.NE.10) GO TO 120
      IF(SHAT.LE.THRFLA(KFRFLA)) GO TO 120
      GO TO 272
274   IF(IM.LE.5) GO TO 120
277   IF(MFLA1.NE.KFRFLA.AND.MFLA2.NE.KFRFLA) GO TO 120
      IF(SHAT.LE.AM2HEV(KFRFLA)) GO TO 120
272   CONTINUE
      DSQ1=SQRT(ABS(1.-4./(1.+SHAT/Q2VECT(M))))
      T1=-SHAT*.5*(1.+DSQ1)
      U1=-SHAT*.5*(1.-DSQ1)
      IF(SHAT.LT.3.*Q2VECT(M+1)) GO TO 124
      DSQ2=SQRT(ABS(1.-4./(1.+SHAT/Q2VECT(M+1))))
      T2=-SHAT*.5*(1.+DSQ2)
      U2=-SHAT*.5*(1.-DSQ2)
      GO TO 125
124   T2=-SHAT*.5
      U2=T2
125   CONTINUE
      T=T1+(T2-T1)*CJRN(0.)
      U=-SHAT-T
      CALL DSDT(IM,SHAT,T,U,WT1,WFDSDT)
      CALL DSDT(IM,SHAT,U,T,WT2,WFDSDT)
      NKINPT=NKINPT+2
      QSQ=2.*SHAT*T*U/(SHAT**2+T**2+U**2)
      DQSQ=Q2VECT(M+1)-Q2VECT(M)
      WGT=(WT1+WT2)
     1 *PI/(BALPH*LOG(QSQ/ALAMB**2)*SHAT)**2
     2 *(T2-T1)
      WGT=WGT*WGTCAS
      WGALQ(M,IWG,1)=WGALQ(M,IWG,1)+WGT
      WGALQ(M,IWG,2)=WGALQ(M,IWG,2)+WGTCAS*DQSQ
      NENTR=1
120   CONTINUE
C-- KEEP RECORD OF QUANTA TOO SOFT TO PASS THRESHOLD
      IF(NENT1.GT.0) GO TO 110
      ICANC(1)=ICANC(1)+1
      NBKCNC(ICANC(1),1)=J1
110   CONTINUE
C
      DO 130 J2=1,NB2
      IF(NENT2(J2).GT.0) GO TO 130
      ICANC(2)=ICANC(2)+1
      NBKCNC(ICANC(2),2)=J2
130   CONTINUE
      IF(NENTR.GT.0) WGALQ(M,IWG,3)=WGALQ(M,IWG,3)+WGTCAS*DQSQ
C-- CANCEL QUANTA TOO SOFT TO PASS THRESHOLD
      DO 250 IB=1,2
      IF(ICANC(IB).EQ.0) GO TO 250
      IF(ICANC(IB).EQ.NBOOK(IB)) RETURN
      ICN=ICANC(IB)
      DO 251 I=1,ICN
      IN=NBKCNC(I,IB)
251   PARACT(IN,1,IB)=0.
      JC=0
      NB=NBOOK(IB)
      DO 252 J=1,NB
      JZ=PARACT(J,1,IB)
      IF(JZ.EQ.0) GO TO 252
      JC=JC+1
      DO 253 L=1,9
253   PARACT(JC,L,IB)=PARACT(J,L,IB)
252   CONTINUE
      NBOOK(IB)=NBOOK(IB)-ICN
      ICANC(IB)=0
250   CONTINUE
C
200   CONTINUE
      RETURN
      END