C***********************************************************************
C $Id: arsplg.F,v 1.2 1996/04/10 12:33:38 mclareni Exp $

      SUBROUTINE ARSPLG(IG,IFLAV)

C...ARiadne subroutine SPLit Gluon

C...Splits a gluon entry into a q and a q-bar entry

#include "arimpl.f"
#include "arpart.f"
#include "ardips.f"
#include "arstrs.f"
#include "ardat2.f"

      INXT(I)=IDO(IP3(I))


C...Allocate space for new parton and new string if there is room
      IPART=IPART+1
      ISTRS=ISTRS+1

      IF (IPART.GE.MAXPAR-10) CALL ARERRM('ARSPLG',6,0)
      IF (ISTRS.GT.MAXSTR) CALL ARERRM('ARSPLG',8,0)

C...Set new pointers
      IDP=IDI(IG)
      IDN=IDO(IG)
      IDO(IG)=0
      IDI(IPART)=0
      IDO(IPART)=IDN

      IP1(IDN)=IPART

      IS=ISTR(IDP)

C...If closed gluonic string, no new string is created. The colour flow
C...which was previously undefined is set randomly
      IF (IFLOW(IS).EQ.2) THEN
        ISTRS=ISTRS-1
        IFLOW(IS)=1
        IPF(IS)=IPART
        IPL(IS)=IG
        IF (RLU(IDUM).GT.0.5) IFLOW(IS)=-1
        IFL(IPART)=IFLAV*IFLOW(IS)
        IFL(IG)=-IFL(IPART)

C...If new string is created set pointers for its partons
      ELSE
        IFLOW(ISTRS)=IFLOW(IS)
        IPF(ISTRS)=IPART
        IPL(ISTRS)=IPL(IS)
        IPL(IS)=IG
        IFL(IPART)=IFLAV*IFLOW(IS)
        IFL(IG)=-IFL(IPART)
        IDNI=IDN
 100    ISTR(IDNI)=ISTRS
        IF (.NOT.QQ(IP3(IDNI))) THEN
          IDNI=INXT(IDNI)
          GOTO 100
        ENDIF
      ENDIF

C...Reset momenta for created quarks and flag affected dipoles
      DO 200 I=1,4
        BP(IG,I)=0.0
        BP(IPART,I)=0.0
 200  CONTINUE
      BP(IG,5)=PQMAS(IFLAV)
      BP(IPART,5)=PQMAS(IFLAV)
      QEX(IG)=.FALSE.
      QEX(IPART)=.FALSE.
      XPMU(IG)=0.0
      XPMU(IPART)=0.0
      XPA(IG)=0.0
      XPA(IPART)=0.0
      QQ(IG)=.TRUE.
      QQ(IPART)=.TRUE.
      QDONE(IDP)=.FALSE.
      QDONE(IDN)=.FALSE.
      INO(IG)=SIGN(1000*ABS(INO(IG))+IO,INO(IG))
      INO(IPART)=INO(IG)
      INQ(IPART)=IG
      INQ(IG)=IPART

      RETURN

C**** END OF ARSPLG ****************************************************
      END