* $Id$
    
C*********************************************************************  
    
      SUBROUTINE LUJOIN_HIJING(NJOIN,IJOIN)    
    
C...Purpose: to connect a sequence of partons with colour flow indices, 
C...as required for subsequent shower evolution (or other operations).  
#include "lujets_hijing.inc"
#include "ludat1_hijing.inc"
#include "ludat2_hijing.inc"
      DIMENSION IJOIN(*)    
    
C...Check that partons are of right types to be connected.  
      IF(NJOIN.LT.2) GOTO 120   
      KQSUM=0   
      DO 100 IJN=1,NJOIN    
      I=IJOIN(IJN)  
      IF(I.LE.0.OR.I.GT.N) GOTO 120 
      IF(K(I,1).LT.1.OR.K(I,1).GT.3) GOTO 120   
      KC=LUCOMP_HIJING(K(I,2)) 
      IF(KC.EQ.0) GOTO 120  
      KQ=KCHG(KC,2)*ISIGN(1,K(I,2)) 
      IF(KQ.EQ.0) GOTO 120  
      IF(IJN.NE.1.AND.IJN.NE.NJOIN.AND.KQ.NE.2) GOTO 120    
      IF(KQ.NE.2) KQSUM=KQSUM+KQ    
  100 IF(IJN.EQ.1) KQS=KQ   
      IF(KQSUM.NE.0) GOTO 120   
    
C...Connect the partons sequentially (closing for gluon loop).  
      KCS=(9-KQS)/2 
      IF(KQS.EQ.2) KCS=INT(4.5+RLU_HIJING(0))  
      DO 110 IJN=1,NJOIN    
      I=IJOIN(IJN)  
      K(I,1)=3  
      IF(IJN.NE.1) IP=IJOIN(IJN-1)  
      IF(IJN.EQ.1) IP=IJOIN(NJOIN)  
      IF(IJN.NE.NJOIN) IN=IJOIN(IJN+1)  
      IF(IJN.EQ.NJOIN) IN=IJOIN(1)  
      K(I,KCS)=MSTU(5)*IN   
      K(I,9-KCS)=MSTU(5)*IP 
      IF(IJN.EQ.1.AND.KQS.NE.2) K(I,9-KCS)=0    
  110 IF(IJN.EQ.NJOIN.AND.KQS.NE.2) K(I,KCS)=0  
    
C...Error exit: no action taken.    
      RETURN    
  120 CALL LUERRM_HIJING(12,   
     &'(LUJOIN_HIJING:) given entries can not be joined by one string')    
    
      RETURN    
      END